$550 Outboard service?

[svranjic]

Hey

Just purchased my first boat and am looking to get the 89 Johnson 70hp 2 stroke serviced. Called a reputable place for a quote ans was told minimum $450 - $550............. :o

Can anyone recommend somewhere I can take it to in the Perth area, North of river, where the cost is a little more reasonable?

Outboard just need a service and tuneup, plugs are fouling and is running a bit rich thus stalling when hot and going from neutral into forward.

Cheers!

[sid_fishes]

so, where do you live?
cheers
ian

[svranjic]

oops left that part out... sorry

Perth area

[Wahoo]

where perth? north south?

[svranjic]

Prefer North of river

[Wahoo]

i know there is a few good dealers in wangerra, (sp) Ozzy park is another,

[stevej]

Hey

Just purchased my first boat and am looking to get the 89 Johnson 70hp 2 stroke serviced. Called a reputable place for a quote ans was told minimum $450 - $550............. :o

Can anyone recommend somewhere I can take it to in the Perth area, North of river, where the cost is a little more reasonable?

Outboard just need a service and tuneup, plugs are fouling and is running a bit rich thus stalling when hot and going from neutral into forward.

Cheers!


new plugs
labour to adjust carbs
drop the leg inspect impellar housing
new impeller
new gear oil
inspect lube all linkages steering pivot tube etc
inspect and asjust throttle assembly and check for wear
inspect steering cable for wear

what else? i think its pretty well on the money

minmimum items id want done
is new impeller and housing check
new plugs
new gear oil
and everything lube and checked
almost everything above and some items im sure ive missed

[iceknight]

fuel pump diaphram, thermostat.... battery check, compression test.... and the likes......... but i guess im just old fashonied about it :O

[Spaniard_King]

May as well throw in a new flame arrester as well eh!!

[Roughasguts]

Mate the motor is not worth that much.
how about having a crack at it your self! order some parts get some oil and plugs a service manuel and let us help you out with some details. Hell it's only a 3 cyl lawnmower, and an old one at that.

[svranjic]

I called another joint and was quoted $350 for service, but was warned it could well be over $500 if the carbies need any work...... Told the bloke bout the fouling of plugs and stalling and he seemed to think a leaking carbie.


Anyhow there is no way in hell Im spending $500+ on servicing the motor, I think considering the age of it and price i paid for the boat it makes it a an unrealisitc thing to do.

I am pretty mechanically minded and am more than willing to give servicing it a crack. I have receipts from the previous owner showing servicing done at a dealership, last july the carbies were cleaned and adjusted and from what he has told me the boat has virtually sat in his garage for the past yr with little to no use. So I am doubting the leaking carbie theory.

I have managed to find a workshop manual, its a pretty broad one covering many models though so its a little difficult to follow.

The plugs in the boat are oily and black, probably not producing a decent spark either. The motor is definately running a bit rich and I think the fouled plugs are contributing to the stalling when hot. The VRO was removed last service and thus the idle etc was rejigged, I dont think the idle was set properly under load.

Anyhow I am mixing the oil in fuel at 50:1 and am going to replace the spark plugs tommorow and see how she runs. From there I think i might have a fiddle with the idle speed screw and see what effect that has. The motor runs fine, starts first turn, idles fine when cold and performs ok, just seems to be a bit rich and intermitently stalls when going into gear and hot.

Any other reasons for stalling when hot?

I prolly should have started a new thread specifically on this topic, sorry

Cheers for all replies so far, really appreciate it!

[oldboot]

I cant recomend enough coughing up the cash to the the genuine paper manual for that motor.

If the johno manuals are anything like the merc ones, it will all be there in detail.

most of the stuff you need to do isn't complicate or expensive in parts, just dirty and time consuming.

When I first started looking at this stuff I could not bleieve how simple and straight out crude some of these motors are.......if you can manage typical motor repair tasks on a car, it should be a dodde.....you just need to be fussy.

cheers

[BILLY THE KID]

Told the bloke bout the fouling of plugs and stalling and he seemed to think a leaking carbie.

the boat has virtually sat in his garage for the past yr with little to no use. So I am doubting the leaking carbie theory


best reason for a carby to leak , no fuel so seals dry up and go brittle and leak like seives . sucking in air may cause the rough running too

[whynott]

$ 550 was the price that I was also quoted for a yearly service.
Can someone let me know what the correct plugs and the gap is for this motor?
Thanks for your assistance.
Graham.

[svranjic]

My workshop manual says Champion plugs QL77JC4 or L77JC4 gapped to 0.040

[Noelm]

OK, I will recap what has been said, and maybe add just a bit, first, you have a very simple and reliable Motor (the VRO shold have been left on, but thats another story) buy the PROPER genuine manual before you start (it will pay for itself first time) if you are even mildly mechanicaly mined, you can do almost anything to that Motor with just basic hand tools, do not start pulling things to bits and fiddling with adjustments before you get the manual, take it step by step and you will be an expert before you know it plugs and gear oil and so on are a cinch, carby rebuilds are also no drama, buy genuine kits, and use all the bits.

[Spaniard_King]

My workshop manual says Champion plugs QL77JC4 or L77JC4 gapped to 0.040


Your workshop manual is wrong the plugs need to be gapped to .030 not 0.040

The plugs quoted are right but use the QL77JC4 as it is a rsister type plug which will give your boat electrical equiptment less greif

[Spaniard_King]

I am not so sure Noel, sure most of its is easy and so it should be but some people will find it hard to get their heads around a proper service manual.

[Noelm]

yep, maybe.

[cormorant]

If you have the previous service records who did the services ? Was it a dealer?
Unusual they would remove VRO unless it was a customer request.

That motor with a lot of cold starts will foul plugs with the VRO disconnected especially if using cheap oil or old fuel. Use XD50 and you will have less fouling and less smoke or smell from day one. Don't run ethanol fuel in that motor.

Do the simple stuff
Check compression so you know what you are starting with.
Check the fuel system and make sure all is clean and clear.
Make sure the choke is turning off on all 3 carbys.
Change plugs. Run the bloody thing and give it a good long run and then check the plugs.
Rough idle etc can easily be wax left after fuel has evaporated.
I wouldn't play with settings till you know what is going on and have a full manual.

Since the bloke kept and passed on the service records have a chat with him as he may well be a top bloke and happy to chat about ant issues he experienced and why he removed the VRO. He may even chat to the mechanic who did the service and help arrange a better prce to resolve the issues since it has done bugger all hours since he serviced it.

[svranjic]

Spaniard_King is right, gap plugs to .030 My workshop manual is aftermarket and covers many models, dunno why it says 0.040........

The boat was serviced by a dealer. According to previous owner the dealer had been nagging him to remove the oil injection for ages as older oil injection systems on johnson motors were prone to failing and it would be safer bet to remove it and mix the fuel.

Before i purchased the boat I did a little research into this as it turned me off buying the boat a bit, being my first boat and all + purchasing a boat with no oil injection. Anyhow my research turned up alot of info regarding failure of the oil injection on this model motor and thus recommended removal of the system. To be sure I also called a mobile mechanic and asked if this removal was reason to be concerned, he agreed I was better off mixing oil in fuel.

I did however ask the previous owner for ALL oil injection parts that were removed which he happily provided and I still have in a box.

Today I removed the old spark plugs which were in poor shape, also NGK brand not sure if proper model. Replaced with spark plugs mentioned in this thread.

I havent touched any settings yet, trying to start with the simple things. Im using Penrite 2 stroke oil and always using fresh fuel.

Where can I get hold of a genuine workshop manual? The one I got now seems ok for broadening my knowledge, I got no probs dropping gear oil, changing plugs etc, but the manual isnt so good and explaining carburetor.

Cheers for all the replies so far!!!

[oldboot]

You can get CD rom genuine manuals for most things off ebay... but they are not as good as the full genuine paper manual specific to that motor.

you should be able to buy one thru a dealer for that brand.... some might not be bothered or discuorage you.....try a different dealer.

One thing I have come to realise is that some of the dealers do not know as much as they should be cause they rely on the factory supplied CD roms... which do not have the detail of the paper manuals much of the time.

There areall sorts of things various mechanics are inclined to rip off stuff.... because thay can be a problem.......perhaps there are some maintenance procedures they are not up with.

Variable oil injection is a very important thing on any sort of modern motor.....if it didn't do something they would not make it variable......the oil mixture in a two stroke motor has significant effects on engine tune......so the carby on a motor with variable oil injection will be jetted to account for that.

cheers

[mercury'srising]

I always thought that VRO stood for variable ratio oil (blend). But an OMC dealer once told me that these models should have had two VRO decals one for"Variable Ratio Oil" and another for "Very Rarely Operates". Stick with pre-mixing your fuel and try not to idle for to long before you shut her down. You need to do a compression test as well before going much further which may help with the fuel load up diagnosis. No need to panick if you don't get a super high reading on the gauge what you are looking for is an even reading on all cylinders. A variance of about 5 lbs. is acceptable. When you do the comp test how about posting the results it may help us to enlighten you further.

MERCURY'S RISING WHILE OTHERS FALL

[Noelm]

OK, some of the early "VRO" systems did need some maintenance, but the later (from I think the late 80's on) are some of the best for reliability, along with Yamaha, and I guess today there is no bad 'self oilers", if it is on the Motor, get it serviced and leave it on, pretty simple really.

[cormorant]

It's the old for $100 I can remove it or for XX unknown dollars I can order a kit, install it , check it all and not warranty it will stay working as I can't remember my training. Yes there has been failures in just about all systems but there is a lot of failures of people not putting oil in the tank and a lot of extra plugs and maintainance and de-carbing motors that all adds up $ over time. Guess it is a case of pay up front or pay gradually with extra oil and service parts. Newer better oils have made it less maintainance to premix but it is not a perfect solution.


This is an article on VRO that has a few facts- obviously written by a fan of it - if you search the author you will also find the diagram that shows simply how it works or should.

Thanks to Continious W and Bill Grannis for this article.
Introduction
Two-stroke outboard motors have traditionally used a mixture of gasoline and lubricating oil as their fuel. A long standing practice was to pre-mix the gasoline and oil together in the boat's fuel tank. This required careful calculation and measurement of oil and gasoline, and particularly in large tanks could be awkward to accomplish. Also, pre-mixing set the gasoline-oil mix to a fixed ratio, typically 50:1. In the mid-1980's outboard manufacturers began to offer oil mixing pumps which would blend lubricating oil from a separate reservoir tank with the gasoline as it was being pumped to the engine. This arrangement offered several advantages: the operator did not have to compute and measure oil for pre-mixing in the fuel tank. The operator just had to keep the oil reservoir full and oiling would be done automatically. Also, the ratio could be made variable to allow for different lubricating needs based on engine throttle setting.

OMC introduced an oil/gasoline mixing system for their outboard motors in c.1984, and called this feature a Variable-Ratio Oiling system or VRO. Over the years some engine failures caused by lack of proper lubrication have been mistakenly attributed to defective VRO components. As a result, some owners of OMC engines with the VRO feature have disconnected the pump and reverted to pre-mixing. This article discusses the history of OMC outboards with VRO, the theory of VRO operation, and the diagnosis and repair of common problems. Suggestions for updating older motors are included. It also dispells some of the myths that have arisen in "dock-talk" about the VRO system. Earlier versions of this article have appeared in BASS & WALLEYE and TRAILER BOATS magazines, the AM-Tech newsletter, and other online resouces. A revised and updated version is presented here with the permission of the author, Bill Grannis, whom we thank for this valuable contribution to our REFERENCE section.

VRO STORY—The Myth of the Mixer
by Bill Grannis
Whenever there is a gathering of boaters, the conversation usually turns to engines, then gravitates to stories about problems. One of the bones OMC owners like to pick concerns the oiling system. A typical conversation that we've all heard at one time or another might go something like this:

"Yeah, my boat smokes like hell at low speeds and fouls the plugs," bemoans one boater. "Must be that worthless VRO pump acting up."
"Uh huh, my neighbor had a blown engine," quips another. "Took out two cylinders on his V-6. The mechanic told him the VRO went bad. He didn't get an alarm or anything."
"Come to think of it," the third member of the group chimes in, "my brother-in-law's offshore rig with twin outboards must have a flaky VRO; one motor always uses more oil than the other."
"My engine is hard starting at times," says a fourth angler, "the VRO pump must be getting weak and the warning horn blows constantly whenever I run at full throttle on my 150."
The truth of these stories is that none of the symptoms described is the fault of the VRO, yet the poor VRO pump gets the blame. Each rig has a different problem that is blamed on the oil pump because of misunderstanding, ignorance, and misinformation. Even many "experienced" mechanics do not have the knowledge of how the system operates and are quick to blame something that is unfamiliar to them.

For instance, the first boat owner's problem (1) is an air leak somewhere in the boat's fuel system causing "foamy" fuel instead of a solid column of liquid. This aerated gasoline has less volume and less resistance causing the fuel pump diaphragm to cycle faster. Each cycle pulses oil into the foamy mix, increasing the oil:fuel ratio to the carbs creating a smoky exhaust.

The mechanic of the second guy's neighbor (2) did not understand that the VRO mixes the fuel and oil internally then delivers the mixture through the fuel lines to each of the carbs. Since each carb receives the same oil to gas ratio, the VRO cannot cause only two cylinders to fail. Since the VRO did not malfunction, there was no alarm to sound.

On the other hand, the brother-in-law's motors (3) have two different year's pumps on them. The later model VRO's pump more oil at low speeds than the original ones did.

The last guy (4) blames the VRO because he once had a car with a weak fuel pump and a replacement cured its hard starting problem. Actually, he only needs a refresher in the correct starting procedure. As for the constant sounding horn at high speed that stops when slowing down, that's a fuel restriction warning, not a VRO malfunction. A lack of oil flow is a pulsing on and off horn every second or so.

A decal is available (OMC P/N 335707) for the dashboard that illustrates the different warning signals and what they mean. This would be for 1995 and earlier motors, since 1996 the SystemCheck gauge uses four LED warning lights that illuminate to indicate LOW OIL, NO OIL, OVERHEAT, or CHECK ENGINE.

A LITTLE HISTORY
OMC introduced the VRO on the V-4 and V-6 engines in 1984. The pump consisted of a combination oil pump and fuel pump actuated by crankcase pulses through an air motor. Gasoline reformulation in those early years contained alcohols and solvents that softened the internal rubber components and caused pump failures and damaged engines. Back then, no company had alarm systems for a pump failure or loss of oil flow. OMC took care of the blown powerheads and improved the pumps considerably.

The VRO2® was introduced in 1986 and included a "NO OIL FLOW" alarm. Changes included an electronic circuit to compare the oil pulses with the engine's RPM, a better oil pump piston, alcohol resistant seals, and a brown fuel outlet for recognition. Unfortunately, the damage was done. Public perception fed by uneducated mechanics put the blame for almost every engine problem on the VRO. No matter what happened to a motor, someone would utter "...must be a bad VRO."

VRO OPERATION 101
Actually, the much-maligned pump is very simple and reliable. It consists of four basic sections:

the air motor,
a fuel pump,
an oil pump, and
a "NO OIL FLOW" alarm system.

Cutaway View of VRO Pump Showing Major Components
The air motor converts the pressure and vacuum pulses from the crankcase to a linear motion. These pulses are routed through a pair of check valves above the engine crankcase pulse fitting. One directs pressure cycles to one side of the air motor's piston (white chamber) and an inverted check valve directs the vacuum cycles to the opposite side (tan chamber).

Each engine revolution moves the piston (dark green) incrementally to one side of the air motor chamber (tan) and compresses the large spring. When the piston (dark green) nears the end of its travel, a small spring unloads a poppet valve located in the middle of the piston assembly. The pressure (white area) on one side of the piston rushes into the vacuum side (tan area) as the large spring quickly pushes the piston back to its starting point.

As the throttle is advanced, the pressure pulse gets stronger because of the increased airflow through the crankcase. This back and forth motion of the air motor's piston (dark green) is what powers the fuel pump and the oil pump. At idle and low throttle settings, the weaker crankcase pulses cause shorter piston movements, which in turn, pump less oil with each cycle. As the throttle opening increases, the stronger crankcase pulses cause greater piston travel resulting in longer oil pump strokes. That means, more oil is delivered increasing the amount of lubricant in the fuel up to a 50:1 ratio.

The fuel pump, which is located in the middle chamber of the VRO, consists of a push-pull piston (orange) and diaphragm with a flapper valve and an inlet check valve. A rod connects the fuel pump piston (orange) directly to the air motor piston (dark green) and the two chambers are sealed from each other by an o-ring. As the back and forth motion is generated in the air motor, the double-action fuel pump's piston (orange) and diaphragm is pushed and pulled by the rod cycling fuel to the carburetors. Gasoline is drawn into the blue area of the chamber, travels through the piston's flapper valve, and is pressurized in the green section on the following stroke.

The oil pump is directly connected to the fuel pump piston (orange) and diaphragm so they work in tandem. As with the fuel pump, oil (yellow) is drawn in through the inlet fitting and a check valve as the air motor starts its travel. On the return stroke, the oil pressurizes, exits directly into the fuel chamber (blue area), and is blended while enroute to the carbs.

DISTINGUISHING VRO's
Of all the traditional two stroke outboards produced worldwide, OMC products have the only automatic lubrication systems with a "no oil flow" alarm. The VRO's electronic circuitry compares the RPM of the engine to the number of pressure pulses from the oil pump piston. As the oil flows into the fuel area, the pressure moves a small piston that actuates a steel pin in the alarm module. The pin's movement is detected electronically and "counted." If the engine revolutions exceed the preprogrammed oil pulse ratios, the warning horn is activated sounding a rapid on and off sequence. Since 1993, the VRO is actually called an oil metering system (OMS). The ratio averages about 60:1, slightly leaner at idle and slightly richer at full throttle. The older pumps idled between 150:1 (prior to 1990) and 100:1 (1990-1992), then richened up to 50:1 as the engine load increased. They are recognized by the brown fuel outlet fitting and/or a wiring harness attached to the alarm module.

The original VRO from 1984 and 1985 had a black fuel outlet fitting and no wiring. OMS pumps have a blue/gray outlet nipple or a blue/gray pulse nipple, or a black fitting held in place by an oval metal bracket and two Torx headed screws. To simplify things just remember that the air motor converts the crankcase pulses to a back and forth motion. Directly connected to the air motor is the fuel pump and the oil pump. The travel of the air motor pumps the fuel and the oil together to the carburetors and the alarm system monitors the oil pressure counts. Just like manually premixing the oil and gas, the VRO (OMS) automatically does the same thing and sends that fuel mixture to the carburetors.

PREVENTIVE MAINTENANCE
There is no mechanical maintenance that has to be performed on the pump itself, but the VRO system should be inspected occasionally for cracked lines, leaks, and broken clamps. One of the most common causes of engine failure is water in the remote oil tank. Condensation and spray can build up over time and, like water in a fuel tank, it stays on the bottom to be sucked up at the worst possible moment. Water pumps through the system as easily as oil, so several time a year use a turkey baster to draw off some fluid from the base of the tank and squirt it into a clean jar. Look for sediment or water settling to the bottom of the container. If you see any signs of contamination, the tank should be flushed clean, the filter (OMC P/N 174377) changed, and the oil line purged. Be sure to read and understand the service manual before doing any of these procedures.

If an oil tank is exposed to the elements such as in an open boat, installing the tank inside a covered battery box will protect it from spray. You can also replace the clear plastic cap with the later model's solid black filler cap (OMC P/N 176217) that provides much better water intrusion resistance. The oil line should be OMC's 1/4-inch I.D. inner "rubber" hose (OMC P/N 333485) without any splices. Early systems had a smooth vinyl oil line that hardened after a few years and sometimes caused air leaks. (Some installations even had 5/16-inch fuel line squeezed down over the smaller fittings.) These air leaks can also trigger "NO OIL" alarms, commonly at startup, idle, and trolling speeds.

Another service tip is to avoid Ty-raps or worm gear hose clamps on this system. The ratchet clamps (OMC P/N 322654) give the best seal and full 360-degree clamping action. Late-model OMC's use a double-wire wound spring clamp (#339277) that also works well in keeping lines air tight. Air leaks and/or fuel restrictions will affect the VRO and usually show up as excessive oil consumption, smoking, and fouling plugs.

If air gets into the fuel, it causes a foamy solution, similar to a head of beer in a tall glass. (A vapor lock situation does the same thing ). The volume of liquid fuel is less and the oil delivered is the same as for a full chamber of fuel. Now you have richer gas oil mix with its resulting symptoms. A fuel restriction such as from a bad anti-siphon valve, kinked line, or a partially plugged filter does not allow a full charge of gas to be drawn into the fuel pump cavity. Again, you get the full shot of oil mixing with less gas. This is also the reason to not disconnect the gas line and run the engine "dry". As you run out of fuel, the oil still pumps, filling the lines and carbs with your favorite TC-W3 lubricant.

Since the VRO depends on crankcase pulses to operate, it is susceptible to backfires from a lean running cylinder or an out of tune engine. If your motor is older than a 1993, make sure it has the blue colored pulse limiter to protect the air motor and the check valves in the pump. Follow the pulse line from the VRO to the engine block and look for a hex shaped fitting threaded into the crankcase. If it has a black face on it, replace it with a blue style (OMC P/N 435009). The crossflow V-6's have a pulse limiter with a fitting at each end and spliced in line with the VRO to crankcase hose. The inline replacement is OMC P/N 435010.

Since 1986 (and on updated 1984's and 1985's), the pumps have an alarm system that operates off the alternator or tachometer circuits. Occasional checks should be performed to make sure the charging system, warning horn, and related parts are operational. The quickest and easiest test is the grounding of the tan overheat temp switch wire to the engine block. To do this, turn the key on, motor not running, and use a jumper wire to ground the tan wire from the motor harness and listen for the warning horn. It should be a loud steady tone. On 1996 and later engines with a SystemCheck® gauge, only the "hot" light will come on, but no horn unless the motor is running. With the SystemCheck® equipped motors you will have to disconnect the OMS (VRO) four wire connector and carefully ground the tan motor harness wire lead to illuminate the "no oil" light.

The warning horn tone sequence tells if a problem is occurring while operating the engine. A rapid on–off sound is a "no oil flow" indication. One beep every 20 to 40 seconds is a low oil level in the remote tank. Of course a steady tone at all speeds is an overheat condition. On V-6's a constant horn at high speeds that disappears instantly when the throttle is pulled back indicates a fuel restriction. Loose connections can also cause erroneous "beeps" and the most common open circuits are battery cables with finger tightened wing nuts instead of stainless steel hex nuts and lock washers tightened with a wrench. Incorrect spark plugs occasionally cause false warning signals, too. Use only the "Q" style suppresser plugs recommended by OMC for your motor. Resistor plugs are not the same thing and may be the source of problems. The factory does not endorse spark plug manufacturer's conversion charts.

SYSTEM UPGRADES
In 1996, the SystemCheck® warning gauges were introduced. A tach with four warning lights or a dash-mounted gauge with the same lights show the type of malfunction that is occurring by which LED is illuminated. The horn sounds for 10 seconds when a fault occurs and the proper light stays on until the problem is corrected. There are indicator LED's for HOT, NO OIL, LOW OIL, and CHECK ENGINE (which means a fuel restriction in a V-6 carbureted motor).

By the way, the SystemCheck® can be adapted (with accessory kit P/N 176709) to any engine with a four-wire VRO pump. [For more information on the SystemCheck upgrade kit, please see a separate article and discussion.]Even better, there's a new VRO (OMS) pump that can be used to upgrade all the previous years and model outboards. The new pump (P/N 5004558) contains various fittings for different outboards, and each internal part is replaceable for easier and less expensive servicing. Part number 5004559 updates all early three-wire VRO's except those found on the two-cylinders. For those outboards, kit number 5004562 is used. OMC also makes a wiring harness adapter (P/N 174710) for the 1984 and 1985 engines that did not have any warning systems. Each OMC (VRO) kit contains the parts needed including a new pulse limiter to install the system correctly.

SERVICING
Since 1991, the OMC factory service manuals include a troubleshooting chart and a section on how to test, take apart, and service the VRO pumps. Besides Torx screwdrivers, you will need a pressure and a vacuum source to test the integrity of the check valves and diaphragms. CDI Electronics' #551-34PV gearcase vacuum/pressure tester work well, as does a SnapOn YA-4000 or the old Stevens pumps.

Even though they are not listed in the parts catalogs, most of the diaphragms are interchangeable. The air motor diaphragm kit is part number 435921 and the fuel pump repair kit is 436095. For those who pre-mix their fuel and oil, these kits allow the repair of the fuel pump section, avoiding the high cost of a new assembly or the re-plumbing and rigging of one or two traditional style fuel pumps.

Do not interchange any of the springs with other pump assemblies. They are calibrated for each model of pump. The latest P/N 5004558 pump is a universal fit that can be used as a replacement for all VRO equipped motors and each part is available for servicing.

When working on a fuel system, check for any restrictions or air leaks which would affect the engine. You can use a clear piece of fuel line connected to the VRO inlet and "T" off to a vacuum gauge. Run the motor at all speeds while inspecting for air bubbles in the line and for any vacuum restrictions above 4-inches Hg. A system with 3/8-inch fuel lines, a clean "spin on" filter, and a quality anti-siphon valve should show between 2.5 to to 3-inches of vacuum at full speed.

Repair and update your VRO or OMS system methodically and by the service manual. Check and test the boat's fuel system for restrictions and/or air leaks, and make sure the oil tank is clean. If you follow these recommendations, you will have a reliable and economical outboard that will keep your boating experiences pleasant.

So, contrary to boat ramp "urban legends", the VRO pump is a simple and reliable oiling system that has been standard equipment on most OMC outboards from 40- to 300-HP for the past 20 years. Most of the misinformation and "scare tactics" about its reliability originate from those who do not understand how the system works, or fail to keep it maintained.

[mercury'srising]

Well how about all that. No wonder it costs so much for a service or repairs with all that junk attached to a poor old 70 2 banger.The extra weight alone must really help with fuel consumption. Just put the oil in the fuel. It goes to the same place and you know it's there at least. But check those compressions, "most important".
I will however agree that the VRO URBAN LEGEND came from boat ramp discussions. Unfortunately the discussions usually involve the VRO owner at the ramp that has just been towed in with a seized powerhead. The conversation usually starts with "Oh' no! not again" This makes it a LEGEND and NOT A MYTH.

MERCURY'S RISING WHILE OTHERS FALL

[lunchcutter]

sh-t hay my uncle just got a 100 hr service for his yammy 4strk 115 hp cost him 450

[svranjic]

Good news!

After giving the previous owner of the boat a call he mentioned he had previously had idle probs before and it was found to be a leak in one of the fuel hoses.

Anyhow, I went over the motor thoroughly and managed to find a leak in the air silencer cover on the carbies. I also found two fuel hoses that had become pretty sloppy.

I took the entire air silencer cover of, replaced both gaskets, replaced spark plugs and zip tied the fuel hose on tightly.

After putting on a new solas prop I also removed the hydrofoil.

Wow. What a difference, boat drives like a dream. Whilst I was on the water I also adjusted the idle speed a tiny bit. No more stalling. I cant believe what a difference removing the hydrofoil made.

I still need to change impellor and gear oil, also need to buy a compression gauge and do a compression check, but Im extremely happy with the way shes running now. Had a great day.

BUT - - - - - - - On river just before I'm bout to head home I put a nice chip in my brand new $300 propellor............. :( :(

Off to the prop shop again on monday

I love boating -_-

[cormorant]

Someone close to you will have a compression guage?