Should I keep my old outboard?

[svranjic]

Gday

Im currently in the process of putting bits and peices back onto my 4.7m Stejcraft fiberglass hull after rebuilding the transom and completely painting the boat.

Im thinking of maybe putting a new outboard on the back of it but got a shock when I found out the price of new outboards....

Ive currently got a 1989 Johnson 70hp 2stroke. The compression on it is good and iv got the vro oil pump hooked up which is still working too. I do however have problems with it missing at low speed and it doesnt idle the best. Ive done a decarb, link and sync, new thermostat, new plugs etc etc
I have a feeling the carburetors need rebuilding as when i tilt the outboard and pump the fuel bulp til it gets tight fuel leaks from the middle carb.

Also it uses a fair bit of fuel which is a paint in the ass, I dont have room for below floor fuel tanks and dont have space or weight capacity to be carrying massive volumes of fuel. I did put a solas prop on it which may possibly be loading it up and causing excess fuel usage????

The motor seems a bit heavy for my hull too, the ass end sits pretty low and needs a hydrofoil to get it to plane a bit better and prevent porposing.

Anyhow my question is what am I best off doing??? a new 60hp 4 stroke is gonna set me back close to $10k. I could look at maybe a 50hp newish 2nd hand 2 stroke but Im not sure if it would be underpowered. Or I could fix up my old johno

Boat is mainly used for fishing, occasionally for skiing / cruising.

Cheers

[STUIE63]

stay with the old motor . just make sure it is propped right . you will save 10 big ones . a 60 4 stroke will probably weigh the same or more as what you have , and going to a 50 2 stroke you will not get any better fuel economy anyway
Stuie

[FNQCairns]

+1

Yeah invest in some shares with that 10k. sounds like you have already done lots to that engine, leaking fuel on tilt is fairly typical, more so if under some artificial pressure at the time, still a carb rebuild never goes astray depending on when the last one was done.

Most new engine purchases are emotional ones and that's Ok, each to their own.

Don't discount a mechanic with an experienced ear so the ability to actually tune an outboard, with outboard age comes variance so the tuneable settings relayed in manuals become less and less reliable.

Sadly as these things go, your engine with relatively little spent (less than the forced warranty servicing costs on a new engine) may give good service for the next 10 years.....your 10k worth of shares by then might be worth enough (if you do you research properly) to buy a brand new 20 footer straight from the showroom floor.

[svranjic]

Cheers for the replies

Looks like I might be doing a carb rebuild..... dont think it has ever been done looking at receipts from previous owner.

What is a good pitch prop to put on these motors for fuel economy???

[Spaniard_King]

I would be keeping it too.

With your boat it should be running the standard pitch 17 but see if you can get the later model 14 x 17 high raked prop(they came out around 1993)

The only other thing which lets them down is the trim motor... keep it well covered in a good corrosion protection agent.

Also those old 70's went better with the standard champion plugs QL77JC4 than the NGK's .If you troll allot you may find the QL78yc plug is better for you.

[Chimo]

Good on ya Garry!!!

C
C

[Vitamin Sea]

+4

Save the coin, when/if the current motor dies do something then, as the other fellas have said make sure it's propped/set up right, if need be take it to a good mechanic (Garry) and spend a few bucks to make it run right.

Should last for years.

Cheers

Bill

[cormorant]

If you keep the good ol one it may be worth buying a digital temp set up with waning buzzer so you can keep an eye on running temps as cheap insurance.

It will give you early warning of possible blockages abut also oil issues and possibly allow you to get away with not pulling the heads off. If the heads haven't been pulled every XX years they can be a risk when pulling with corrosion and stuck bolts.

Keeping a note on the dash of max revs achieved and speed will give you a reference so you know if a problem starts with the motor. Every time you take it out check speed and WOT . Good oil, fuel , fresh impellers and correct tuning should give you a lot of hours without too much expense.

If it is using tote tanks move it forward to get better weight distribution or any other weight forward and beware of waves ove rteh back and swamping or have atransom plate installed to stop any wash coming in.

[deckie]

Sounds like a good motor that may respond well to some work by a pro like Garry. i'd keep it too.
Pretty sure they weighed around the 110-115kg mark and the lightest 60hp available (suzi) is around 105kg. Its probably upper end but fine weight wise for the stejcraft but you still wouldnt likely make much difference with a 60 4 stk.

Side note...just spotted around the corner out on the street yesterday, a guy selling an early 80's savage paciific in average nick with what i think is a 1998 Johnno 70 on the back that looks in good nick. Temped at the price to pick it up just for the motor and allocate $1500 to it. Never heard anything but good reports about 70 Johnno's but never owned one myself. Then gotta find the right boat for it of course...hmmmmm 8-)

[gazza2006au]

the problem with old engines is the bolts seize from salt and snap when u try removing them i had a 70hp johno most of the exhaust cover bolts snapped i called a few shops they wanted $45 per bolt and there is a lot of bolts! u could still sell your 70hp johno on ebay or in a classified for $1600 there abouts and your carby is probably leaking due to build up of dirt in the seat not letting the needle properly seal once the carby is full of fuel all u need to do is remove the carbies from the engine unscrew the carby bowl remove the float pin and float than the needle and blow compressed air through the seat or replace it along with the needle should be $8 per carby

[svranjic]

Cheers for the replies!

Unfortunately I live in WA so cant access some of the expertise on ausfish....

Taking a look at old receipts Previous dealerships and mechanics who have worked on the outboard have been putting ngk plugs in it. Theyve got no idea. Some of the quotes I have been getting for servicing and so forth have been enormous. For example $550 - $650 for basic service, $200 to change thermostat. $1500 to rebuild carbs.

Like I said earlier I have changed the plugs with correct Champion ones, changed thermostat, changed gearcase oil, completely new impeller and impeller housing, decarb, link and sync, tested and reconnected vro...... not sure why it was disconnected when it is the vro2 unit which had most issues rectified.

I think the carbs could do with a rebuild, the rebuild kits including the floats are $18 US each, so thats $84 including shipping. I think I can a handle the carbs. Also looking at getting a poper omc workshop manual for it.

I have done a link and sync but havent touched the timing or looked into power packs etc. Need to check the primer solenoid to make sure it isnt leaking. Cant really think of anything else that would cause a low speed miss / intermittent idle.

What are these old 2 strokes supposed to idle like anyhow???

Im a uni student so saving 10k on a new outboard is a massive thing. Especially considering I have spent a fair bit restoring it and doing rhe transom etc

[gazza2006au]

make sure its firing all on 3 cylinders and when getting a manual stay clear of the clymer manuals they are horrible! go on ebay and get a manual its in CD form and shows everything all in great detail and cost under $10 if u get a manual from ebay as an example get one that shows 2-70hp rather than one say 70-200hp as the manuals always picture the larger HP motor in the pictures in that range if u get a manual from the USA ebay they send u an email instantly after payment with a download of the manual sure beats paying 3 times the amount for the clymer manual that doesnt goes into details of anything

[cormorant]

Buy a original manual.

Fuel pump is the other one on older models that dies especially with newer fuels but you have commented that yu have reconnected teh oil system so I assume you have done all tests.

Good you have a bit of history of the motor.

Don't get sucked in by silly quotes. Ask around fishing and boating club and try and find a older ex Johno mechanic ( a real qualified one not a backyarder) locally. Many shops don't like older motors as they can't turn over the work quick enough and know that when they snap a bolt it will take time. That time they could be spending on another service aking bigger dollars..

They were never a silky smooth motor but if you think it is a miss pull a plug lead and see if it is consistantly 1 pot that it is occurring on. Swap / Move plug and lead and even coil to see if you isolate the problem. Look fpr wear on the plug leads and start it at night or in dark shed and carefully ( I mean very carefully) look for a stray spark shorting from a pluf lead or cap. Simple things like the plug holders may need the tangs bending to grip and connect properly with the plug. Airleaks can make them idle rough as well.

If you have compression , spark, fuel and water you are 90% of the way there.

Someone on here may have a original service manual who would copy the carby rebuild pages and tuning pages for you.

[svranjic]

I forgot to mention it always misses when cold...... as soon as I launch from the ramp it misses sometimes quite badly until it warms up.

So I should probably check the spark and electrics before I go jumping to conclusions about fuel supply issues. I will still rebuild the carbs though seeing as I will be keeping the outboard now.

I do have an aftermarket manual which is actually pretty crap. It is very generalised and not specific enough, ie poor diagrams and descriptions.

[Matt76]

I'm gonna go totally against the flow here. How much would you likely spend to get the old one fixed up? Is it worth pouring more money into it? Get a new one and you will see another 20 years before you have to start asking the same question.

[Roughasguts]

If the old Johnie lets you down on start up! and runs rough at idle! and lacks pick up until warm........Think you may have a dud Coil!!

Just need to find the dud coil and replace it easy. (second hand will do)

Oh yeah fix the leaking carb (replace the gasket easy to make a new one) could be dangerous!!!

Cheers

[svranjic]

I just had a look and the Solas prop that Iv got on it now is a 13.5 x 15

This prop also causes motor to rev at WOT higher than the recommended rev limit. So I make sure I never run it at full throttle to avoid damaging the motor.

[FNQCairns]

SV would you by any chance be talking about a 'sneeze' when you say it misses until warmed up?

It's good you listened to Garry on the champion plugs, those engine where built around the plug and that brand specificly, nothing else compares, it's a quick way to assume the quality of the mechanic working on those engine if they are happy to see you off with NGK...it's just not done.

[svranjic]

Nah its not really a sneeze, a definite miss.

I just noticed a 2008 60hp etec for sale second hand with low hrs they are wanting $6500

Still not worth upgrading???

I am about to invest in carb rebuild kits, a genuine omc manual and some coil packs. Not sure bout the coil packs, should really test spark first with an inline spark tester. My money is still on those carbs, they are definately leaking as the air silencer leaks fuel.