Motor flushing question.

[URAGANGI]

I've been thinking about a better way of internal protection against corrosion.
You know how you can flush your motor with muff's or a good run in a barrel of water. Does this really do an efficient job of removing the salt from the moving parts from your cooling system?

Could you induce an oil into that water being cycled inside your engine.Would this help protect the internal workings of the cooling system or would this do harm to your motor in the long run? Or why would you even bother?

Any theories on this Idea. The Good The Bad and The Ugly
cheers
Gav.

[nigelr]

Gav do a search of your topic in this (boating) forum.
Should get several pages of interesting reading, I did this very thing a week or so ago.
Cheers.

[Tickleish]

You've got too much time on your hands;D

I have never heard of an outboard that has been flushed after every use failing due too internal corrosion.

I think flushing is sufficent.

[Tinshack]

Viper Fish, I run the motor with muffs for approx. 5 mins till thermostats are open then run MACS engine flushg through the cooling water. I had purchased an older 95 model motor with low hours but unknown history. It used to overheat, so took off heads & was all full of salt, minimal corrosion but packed with salt. When I first started using MACS I had bits of salt the size of your thumb nail dropping out through the exhaust, so it certainly loosens salt deposits. Since running this every time I flush the motor I now have no salt in heads & issues with overheating & hopefully peice of mind that the rest of the motor & galleries are being being looked after when sitting in the shed between fishing trips. MACS is a bit expensive but you only use 75ml each flush & has solved my issues. MACS looks like & feels like a soluable oil but not sure. Be careful what you use as it may effect water pump, seals ect.. & stuff your motor internals & cost big $$$ to fix. Cheers.

[reefer]

Suzukis and other engines have a flushing point on the side of the shaft. The point is plugged and can be replaced with a 3/4 inch gardina hose connection. You can simply connect the water hose to the connrction and flush the engine more efficiently than using muffs and you do not need to run the engines. Just wait for the water to come through cold, disconnect the hose and the fitting and then just replace the plug.

Hope this helps.

[URAGANGI]

Viper Fish, I run the motor with muffs for approx. 5 mins till thermostats are open then run MACS engine flushg through the cooling water. I had purchased an older 95 model motor with low hours but unknown history. It used to overheat, so took off heads & was all full of salt, minimal corrosion but packed with salt. When I first started using MACS I had bits of salt the size of your thumb nail dropping out through the exhaust, so it certainly loosens salt deposits. Since running this every time I flush the motor I now have no salt in heads & issues with overheating & hopefully peice of mind that the rest of the motor & galleries are being being looked after when sitting in the shed between fishing trips. MACS is a bit expensive but you only use 75ml each flush & has solved my issues. MACS looks like & feels like a soluable oil but not sure. Be careful what you use as it may effect water pump, seals ect.. & stuff your motor internals & cost big $$$ to fix. Cheers.

That's what I'm after. If this product is expensive I'd look at as an investment. Mac's could be a small price to pay other than BOAT: (bring out another thousand) I've always had a passion for what ever burns fuel and always looked after them. Thanks for your time!
cheers
Gav.

[jason p]

Suzukis and other engines have a flushing point on the side of the shaft. The point is plugged and can be replaced with a 3/4 inch gardina hose connection. You can simply connect the water hose to the connrction and flush the engine more efficiently than using muffs and you do not need to run the engines. Just wait for the water to come through cold, disconnect the hose and the fitting and then just replace the plug.

Hope this helps.

mate i used to do thjis with my zuk and then i read in the manual that it was not the prefered way to flush and that zuk recomends using mufs. just a heads up.

jp

[reefer]

Jason P,

Thanks mate, I used the muffs but the bloke who services my engines reckons it is better to use the side flush....who knows! but not had any problems with 140's or 175's but i do flush them every time i use them.

Cheers,

Phil

[TheRealAndy]

You've got too much time on your hands;D

I have never heard of an outboard that has been flushed after every use failing due too internal corrosion.

I think flushing is sufficent.

I have heard of an outboard failing.. Honda 20hp. Flushed after every use.

I also am good friends with an ex pro fisho that used to run yams out near swains. He never flushed his outboards and never had a problem

There is also a common misconception that running your engine untill its hot will disolve salt more effectivly. Salt, as in the type found in the ocean dissolves in cold water just as effectivly as hot water.

Water can only dissolve a certain amount of salt before it becomes saturated, so using a drum might seem a bad idea?

I think from memory, salt (NaCl) is most soluble in water, so one would have to question the use of additives when flushing?

Me personally, I dont listen to anyone on this topic. I just put a large amount of fresh water through my outboards after each use. What you want ot avoid is water sitting in galleries, but I am not sure of the best way of doing this. I tend to tilt my outboard up, then down. Then do the same thing next day. If I am using it everyday i dont even bother flushing it.

[URAGANGI]

Andy thanks for the tips. From what I'm learning so far, is that most corrosion faults tend too start in the galleries. If you can keep the salt content down as much as possable, the likely hood of problems should be narrowed. and with using a drum for the flush I usually change the water over, as not to saturate the water content with salt, That's if your doing repedative flushes.
Cheers
Gav.

[Argle]

Jason P,

Thanks mate, I used the muffs but the bloke who services my engines reckons it is better to use the side flush....who knows! but not had any problems with 140's or 175's but i do flush them every time i use them.

Cheers,

Phil

I was told to use both! Muffs first then give the side plug a hit.

Cheers
Scott

[URAGANGI]

Argle I'd use both your options. Two is better than one, it's a top alrounder.

[kizza1]

just to clear a few things up.
people run the engines till there hot when flushing so that the thermostat opens which in turn means they clean the whole system not half. it has nothing to do with the tempreture of the water disolving the salt.

secondly the fitting on the powerhead is used to flush the outboard when it is moored on the water and you cannot flush them the traditional way with muffs.
flushing with earmuffs clears the whole system whereas the powerhead fitting doesnt flush the watertube or waterpump.

some outboards have a fitting in the telltale to back flush the engine. this is used only when the telltale blocks up.

[TheRealAndy]

just to clear a few things up.
people run the engines till there hot when flushing so that the thermostat opens which in turn means they clean the whole system not half. it has nothing to do with the tempreture of the water disolving the salt.


So you are saying that when the thermostat is closed, water only flows through half of the outboard?



secondly the fitting on the powerhead is used to flush the outboard when it is moored on the water and you cannot flush them the traditional way with muffs.
flushing with earmuffs clears the whole system whereas the powerhead fitting doesnt flush the watertube or waterpump.


Thats odd, when I use the 'powerhead fitting' on my outboard (yam 50 4 stroke) the water seems to run through the water tube and the waterpump.



some outboards have a fitting in the telltale to back flush the engine. this is used only when the telltale blocks up.

The 4strk 50hp merc we have on the rescue boat at the yacht club has one of those fittings. The manual says to flush the outboard, connect the hose fitting to the telltale an run at idle. I guess the manufacturers who wrote the manual got it wrong.

[oldboot]

I flush in a a big black tub $50 from bunnings......I run the motor till I feel warm water comming out the bottom of the leg.

If you think running the motor for 5 minutes will open the thermostst you are dreaming.....likewise if you think flushing while the motor is still warm means the thermosts will be open, dreaming likewise..as soon as the cold water hits the thermostat it will close.

considering that there would be maybe 100mL tops of salt water still in the motor after the drive home and with regular flushing there should be little hard salt in there...the 100 odd litres in my tub should be abble to carry any salt that is there and dilute it sufficiently.

I tank run my motor before going out and again when I return....my motor always starts on the ramp.
I also tank run my motor if I have not had the boat out for a while.

As far as oils preventing corrosion......yeh well not at all well when there is constant moisture arround, and any mineral oil is likley to damage rubber parts in the cooling system... most impellers are rubber.

There was a craze of using soluable oil in car radiators back in the 70's& 80's..what a horrible idea... the alloy still corroded, the oil caused the ruber components to perish AND the oil combined with any other muck to form this horrible glug that clogged stuff up.

Have thaught about detergent..... but if there is residue..this may be corrosive in its self.

If I was to use detergent I would use it as a remedial solution and before I took the boat for a run, or before another clean water flush

Lots of people only think about salt when flushing, but, thre are other things that get into you cooling system, sand and bits of weed among other things.

A good long flush in a tank, where you can give the motor a little rev has a better hope of dislodging this stuff.
I have seen sand and a few bits of weed in the bottom of my tub after flushing.

If you are not tank flushing you simply don't know what came out.

As for the anticorrosion products....I simply don't know...if they would tell what was in them one could make an informed opinion.

cheers

[Argle]

I should add that when using the plug in fitting that it is to be done with the engine shut off as the waterpump does not see any of the water - being at the bottom of the leg.

Cheers
Scott

[TheRealAndy]

I should add that when using the plug in fitting that it is to be done with the engine shut off as the waterpump does not see any of the water - being at the bottom of the leg.

Cheers
Scott

This is a cut and past directly from mercury instructions:

Flushing The Cooling System
Flush the internal water passages of the outboard with fresh water after
each use in salt, polluted, or muddy water. This will help prevent a buildup
of deposits from clogging the internal water passages.
IMPORTANT: The engine must be run during flushing in order to open the
thermostat and circulate water through the water passages.

1. Place the outboard in either the operating position (vertical) or in a
tilted position.
2. Remove propeller. Refer to Propeller Replacement.
3. Thread a water hose into the rear fitting. Partially open the water tap
(1/2 maximum). Do not open the water tap all the way, as this allows
a high pressure flow of water.
IMPORTANT: Do not run engine above idle when flushing.
4. Shift outboard into neutral. Start the engine and flush the cooling
system for at least 5 minutes. Keep engine speed at idle.
5. Stop the engine. Turn off the water and remove hose. Reinstall the
propeller.

[jason p]

just goes to show that different makes of engines require different methods of flushing and we all should refere to our manual.
all motors using muffs require the motor run for optimum flushing but when it comes to the plugs in the flushing ports it seems that they varry some what.
i just had a quick look in my zuk manual and it does state in bold ENGINE NOT RUNNING, when using the flushing port plug!

jp

[TheRealAndy]

just goes to show that different makes of engines require different methods of flushing and we all should refere to our manual.
all motors using muffs require the motor run for optimum flushing but when it comes to the plugs in the flushing ports it seems that they varry some what.
i just had a quick look in my zuk manual and it does state in bold ENGINE NOT RUNNING, when using the flushing port plug!

jp


My yam manual says not to run the engine when using the flushing adaptor as well.

[oldboot]

I recon it is realy worthwhile getting a servica manual for your motor, at leasth then you can consider the recomendations and look at the exploded diagrames.
looking at those diagrames should give you a good understanding of where the water comes and goes.

As I have said i realy prefeer the tub....it is soo much quieter and the motor is operating the way it is designed, with the leg immersed in water.

Besides you don't have water pissing everywhere,and after you can run the water onto the garden or lawn.

If you fill your tank up to the cav plate the water intakes should be properly immersed and so should the exhaust.

If you don't immerse the prop where the exhaust come out, the exhaust system does not present the correct back preasure for the motor......this is why you sould definitely run the motor only at idle using muffs

As far as this 5 minutes opening the thermostat......hmmm.....it takes me longer than that to get warm water out of the leg.

cheers

[Argle]

This is a cut and past directly from mercury instructions:

Flushing The Cooling System
Flush the internal water passages of the outboard with fresh water after
each use in salt, polluted, or muddy water. This will help prevent a buildup
of deposits from clogging the internal water passages.
IMPORTANT: The engine must be run during flushing in order to open the
thermostat and circulate water through the water passages.

1. Place the outboard in either the operating position (vertical) or in a
tilted position.
2. Remove propeller. Refer to Propeller Replacement.
3. Thread a water hose into the rear fitting. Partially open the water tap
(1/2 maximum). Do not open the water tap all the way, as this allows
a high pressure flow of water.
IMPORTANT: Do not run engine above idle when flushing.
4. Shift outboard into neutral. Start the engine and flush the cooling
system for at least 5 minutes. Keep engine speed at idle.
5. Stop the engine. Turn off the water and remove hose. Reinstall the
propeller.


Sorry should have mentioned that it was in regards to a Zuke - upshot is READ THE MANUAL!!!!

Cheers
Scott

[URAGANGI]

Is there any marine teckies or mechanic's that would like too shine a little light on this subject. What do you guy's do when your given the job too flush or purge a motor do you follow the manufactures advice as stated in the users manual.? Or is it sufficient enough just to tub the motor and then carry out what ever work is required.? What do you guy's reckon is the better The Tub or the muffs.?

Cheers
Gav.

[smashed crabs]

I had two Johnson 40's , one on a dory and the other on a small tinny .
The Johno on the dory i abused the crapper out of it , run it in mud and sand and tacked up nearly 2,500hrs on it and never ever flushed it .

The other i did not use as much and i tacked up 600hrs on it , i also abused this outboard like i did the other and never flushed it but this one choked and died big time from crud build up .

You dont use it you lose it , Y

[Fed]

If you're going to flush in a tub you want the water at least a couple of inches above the cav plate.

[PADDLES]

justto throw another spanner in the works with regards to heat, if your engine gets too hot the salt will chrystalise and attach to the steel, that's why raw water cooled stern drives have their thermostat set lower than fresh water cooled.

i go for the high flow option when i flush our stern drive, i use spear water and heaps of it, i also use an 18mm hose to get maximum flow, run it up to temperature (even though our motor doesn't get the chance to cool down because the ramp is just around the corner) and leave it go for 5-10 minutes and let the thermostat do it's job at maintaining the correct temperature.

[oldboot]

Considering the cooling water intakes are usually well below the cav plate and when on the plane the cav plate will be barely immersed...I would like to hear the reasoning behind the "need" to immerse any furrther than the cav plate.

I usualy do go an inch or so over the cav plate.... but as long as the cooling water intake is is well under water I don't see the "need" to go deeper.

As far as what the outboard mechanics do.

When you send your boat in to get the motor serviced, they should be dropping the end off the leg, to get access to the impeller and they should be taking the plate off that gives them access to the thermostat assembly.

The bloke I use stuffs a hose ( bare hose end) in all the appropriate holes while they are open.

When I took the young bro'inlaws 30hp merc in for a service they got quite a bit of sand out.....apart from that the cooling system was very clean. I certainly saw a much stronger flow of water afterward.

If the motor is to be tuned, they have to tank the motor, to provide the correct exhaust back preasure.

As far as using hose & muffs / coupling.......I understand excess water preasure is to be avoided, because it disrupts the flow in the cooling system and it my not flow properly.....the word is adequate volume of water but not excess preasure,

I am a firm believer that all outboards can benifit in a good high rev run on the boat in good clean water.......then if you flush out very soon after getting home, no salt has a chance to concentrate or crystalise.

Of course allowing the motor to idle a little to cool before draging it out of the water will give less heat to dry or concentrate any salt.

cheers

[kizza1]

Is there any marine teckies or mechanic's that would like too shine a little light on this subject. What do you guy's do when your given the job too flush or purge a motor do you follow the manufactures advice as stated in the users manual.? Or is it sufficient enough just to tub the motor and then carry out what ever work is required.? What do you guy's reckon is the better The Tub or the muffs.?

Cheers
Gav.

i did give a marine mechanics opinion however a couple of guys on here refuse to believe it.

muffs are better at idle but the tub of water is better if you rev the engine as it will increase water pressure and volume past that of your ordinary hose

as for height of water in the tub. it depends on the model. some require the water to be 3 at the waterpump height to create suction at the pump and others just need the water to cover the pickup grate.

while your engine is at rest or idle on the boat the water level is generally at least 2-3 inches higher than the cav plate.
once you start to accellerate the cavplate will come close to or even leave the water. but through water pressure and a pre primed system it will continue to suck water through.

lastly there is no sense in backflushing througha telltale with the engine running as the waterpump is trying to force the water back against the direction of the hose. this will wear out your waterpump. i have seen it before. some of the rubber off the blades was melted to the inside of the stainless waterpump housing.

[testlab]

just goes to show that different makes of engines require different methods of flushing and we all should refere to our manual.
all motors using muffs require the motor run for optimum flushing but when it comes to the plugs in the flushing ports it seems that they varry some what.
i just had a quick look in my zuk manual and it does state in bold ENGINE NOT RUNNING, when using the flushing port plug!

jp

In my opinion, the right or wrong way to use ports will depend on how the flushing ports are plumbed into the cooling system, and unless one has the true and correct info and the ability to interpret it, on modern outboards the maker knows best. For example,

Are they on the inlet or outlet side of the thermostat? Are there bypass valves or passages?

Is there a chance of damaging sensors due to water pressure, etc?

Is the running of an engine using cold water through the ports going to cause
excessive wear if it is running when plumbed on the outlet side of the thermostat?

Flush muffs and drums are pretty much foolproof so I think if in doubt use those until you know how to use the flushing ports on any particular motor. IMO, the engine must be running when on muffs - tap pressure alone would rarely overcome air pressure in the galleries and circulate through the engine.

Depending on the maker/model, often the tell tale is where the water enters the engine and seeing tap water come out the telltale (when on muffs and engine off) only means it reached the inlet to the powerhead and not actually gotten into the galleries. Running the engine on muffs/drum guarantees its getting where it should.

Anyone got change from 5c?

Cheers, Dave.