Outboard Overheating

[gaffa]

Guys,

Anyone any ideas relating to solving the following problem on my Mariner 4stroke 115bhp new in 2003, regularly serviced and little used(well since I took it over 1 year ago)

 

The engine runs sweet as a nut below 4000 rpm but as soon as I open it up above 4000 rpm it lasts a couple of minutes and then the overheating alarm sounds and the protection cuts in requiring a return to neutral until alarm resets and off we go again .

 

The tell tale is working OK and I have had a new thermostat fitted which I originally thought had cured the problem.

 

Unfortunately Saturday's trip out showed it hadn't. and that it was actually overheating as steam was wafting from it on tickover whilst the alarm sounded.

 

The boat ran perfectly all day as long as I didnt exceed 4000rpm.

 

The engine is regularly serviced by Holes Bay Marine who have confirmed they have fitted a new water pump impellor at each service.

 

My current plan is to get a waterpump Flowrate test carried out on it which could point to either a faulty water pump or clogged waterways but is there anything else that you know of that should be checked either prior to or during the test that could cause the same symptoms ?

 

Any Help very gratefully received

 

Its restricting my fishing area !!!

 

Pete

 

[Adam F]

Pete,

 

I'd personally get it down to the people that (are supposed to) know...

 

My 50hp Mariner had a very similar problem but was intermitant, and after a few months of DIY checks and guesses at the problem it went bang - result, 6k lighter = new engine, your's would be alot more....

 

Just another thought, surely at that age it is still under warrenty?

[gaffa]

Adam,

3 year warranty as far as I'm aware.

 

Engine was supplied and serviced and maintained solely by Holes Bay Mariine.

 

They have recently done the annual boat antifoul and anode replacement etc and engine service.

 

The problem was only noticed when I got the boat back.

 

Thats not to say it wasn't there before as due to the weather it was unlikely that I could have opened her up for any length of time.

 

But with the speed restriction removed from the harbour it showed itself.

 

Holes Bay Marine have since managed to replace the Thermostat without taking the boat out of the water and have run the boat under load at above 4000 for about 30mins on the mooring with no problems- Hence I thought it was sorted.

 

To do any further checks will probably involve taking her out of the water again

so I was wondering if there was a list of things to check whilst she was high and dry that anyone could recommend.

 

Very Concerned to hear of the problems with Your mariner.

 

Did you find out the problem when it failed- Was it Blocked waterways?

 

Pete

 

[Adam F]

To be fair Pete my Mariner was a ropey anyway - overheating was just one symptom, I think the big end went in the end..

 

Running them even with the fast idle engaged is not the same as running them on the water.

 

Also - I guess one of the problems you may have is flushing the engine through after use if you are on a mooring?

[Afishionado]

To save spending money at a dealer when you can do a bit of diagnostic yourself I would sugest that you remove the thermostat and run the engine without one at all (this can do NO harm at all all a thermostat does is give you a quicker warm up time, although there will be someone who will talk about running too cool making the sun stop shining ignore them for the perpous of this test). If the problem does not occur with it out then you had a sticking thermostat. If it does give an overheat warning then the problem is likely to be a blocked waterway in the cooling system or a worn or faulty water pump (impeller ?)

 

A hand test of a correct teperature is a degree or two over warm coming out of the tell tale.

 

Bad news could be A cylinder head gasket fault

A blocked waterway within the engine

 

Not so bad news could be a Worn or faulty impeller (often found in engines that have had little use and stood idle for a long time).

A worn waterpump casing.

 

Mad Mike

[gaffa]

Adam,

To be honest I have Never Flushed the engine through whilst on the mooring.

 

I suppose it could be done but I don't really fancy hanging over the transom onto the slippery engine to try and fit the muffs .My Transom is virtually at water level

 

With regards to the fast Idle it isn't functional with my engine although it is fitted to the throttle mechanism I think its locked off cos I can't move it.

 

I think they made sure the boat was securely fastened to the mooring and drove the boat into the bow buffer fender and opened it up keeping it reving above 4000 but not going anywhere?

 

Again its not exactly the same as when under sea conditions -Probably increased the erosion on the opposite bank though.

 

I Have this feeling that it is the waterways being partially blocked , Any ideas about how to unblock them ?

 

There wouldn't be a wonder chemical on the market that you could suck in an recirculate for a few hours and Hey Presto Job Done would there?

 

If So What is it?

 

Is Saltx Up To the Challenge?

 

Pete

[Afishionado]

Quote........have run the boat under load at above 4000 for about 30mins on the mooring with no problems

 

Ask them how they did this. I know how it should be done which would involve removing your prop' and replacing it with a special device that when rotated creates water drag without thrust. I would be interestad to hear their answer. To be honest have not heard much good about Holes Bay Marine and Suzuki which is possibly one of the reasons they lost the franchise. I have also found them to take the P with their prices. ie a quote of 10 hours at

Edited April 16, 2007 by Afishionado

[gaffa]

Mike,

Thanks for Advice,

 

Its not the impellor as a new one has been fitted last month

The Thermostat is also new and has made no difference. although I haven't run it at speed without the thermostat.

 

Next step is checking cooling water flowrate and determining whether its a water pump,waterway or headgasket issue.

 

The tell tale temp is fine at tickover but haven't been able to check it at speed.

 

I'm hoping its the cheapest of the options but with my luck it wont be.

 

Noticed the abscence of Pride Of Morpork 2 on Saturday did you have any luck with the Fishees?

 

I got back on berth around 7.30 in the evening with no fish to show for a very long but nevertheless enjoyable day.

 

Pete

[Afishionado]

Thermostat is also new

 

I noticed this comment in your first post. Being an old sceptic with cyinical tendencies my suggestion is based on " It may be new but is it working?" Really, do try a run inc' high speed without the thermostat just to see if the fault is still there.

 

Also as a second home test if it still alarms when running over 4000rpm for any time. Get it to trigger the alarm, immediately slow down and put her in neutral and check the tell tale water temp by hand. If it is BOILING hot then you do infact have a fault. If it is not that hot but just a bit warmer than hand wash water then you may have just a faulty sender unit. These are tests that you can do yourself for free.

 

Lastly if you need a Suzuki specialist take the boat to Yellow Penguin at Mitchells rather than HBM.

 

Mad Mike

[Afishionado]

Noticed the abscence of Pride Of Morpork 2 on Saturday did you have any luck with the Fishees

 

Not brilliant

We went to the Ledge* on the basis of all the reports of Bream over 2 tons throwing themslves on to bare hooks. When we got there it looked like a 'Park & Ride' car park must have been over 30 boats. We found a spot near Adam and fished for 2 hours without a bite even though we groundbaited.

So we b***erd of and found a little rough patch somewhere off Southbourn about a mile or so out. It turned out to be dog fish central but we had a load of fun fishing on light tackle. Also Wrass and a bull huss which gave my mate Mark a good fight on a light spinning rod.

 

Mad Mike

[Coddy]

Hi Pete

 

I have a Mariner 60hp 4-stroke

 

Had a similar problem to yourself and took it to Select Marine in Turks Lane who are Mariner/Mercury agents.

 

To cut a long story short my problem was a blown gasket between the engine and gearbox, the gasket had blown between the exhaust and waterway allowing the water system to be pressurised by the exhaust. There is also an

Edited April 16, 2007 by Coddy

[Newboy]

 

SaltX is supposed to be good to flush out the engine with, I suspect you will need to lift the boat out to do this however.

What if he mixes up 20 litres of saltx mixture in a contain, then feed it thru via muffs, let it flush for 30 seconds or so, stop engine let mixture slush around inside abit (say 15 minutes) then start the process again until misture runs up, this process should be enough to soften any salt deposit inside the engine.

[britboard]

pete,

if your engine is the one i think it is you can back-flush with a hosepipe if your tell-tail is a female thread buy a hozelock fitting and screw it in and at the end of the day attach the hose and flush. we do work at EP barris the mariner distributor and thats the way they test run engines for delivery, i have been using that method ever since i got my boat and never had any problems.

 

Simon L

 

[Maverick Martin]

Select Marine are Mariner agents with Yellow Penguin (next door to Select) being Mercury and Suzuki agents

[gaffa]

Guys ,

Thank you all for advice Very varied and helpfull.

 

I will see what happens this weekend and will firstly remove the thermostat and try the tell tale temperature check and work from there.

I think its a genuine fault though as I could see steam coming off the outboard after alarm went off.

 

Simon,

With the backflush method is the prop in or out of the water and what hose pressure is recommended.

I assume the engine needs to be running to get the water to circulate but what if I took the Thermostat out? does it still need to run?

 

 

Mike,

Only guessing about Holes Bay Marines method of testing I wasn't there to see them carry out test, so guessed when they told me they had carried out an on load test/

 

Interesting feedback on them though I'll be more wary in future.

 

Its a pain not to be able to do anything during the week due to distance etc.

 

 

I'll let you know results as the saga progresses.

 

Pete

[britboard]

Simon,

With the backflush method is the prop in or out of the water and what hose pressure is recommended.

I assume the engine needs to be running to get the water to circulate but what if I took the Thermostat out? does it still need to run

pete,

 

the back flush method is a way of flushing your engine after you have used it on the dockside, it might cure your problem if it is a soft blockage and can be blow clear, but i was suggesting it as a way to flush your engine after you have had a dealer find the cause. When you have finished for the day and are tied up connect a hose and leave it flowing through your engine whilst you tidy up it will fill the engine with fresh water and as long as you tilt down to drain it and dont start it up again before the next time you go out it should help with any internal corrosion, DON'T run your engine with the prop in the water using this method as the engine will try to pick up water from the lower gearbox, but if everything is clear of the water it will be ok to run it as you are still filling the waterjacket but the flow is reversed.

I run mine straight of the mains water which is about 3bar.

ONLY USE THIS METHOD IF YOUR ENGINE HAS THAT FITTING

if you post up your engine model No and year i can check for you.

 

If you think the problem is a blocked passage put you engine in a wheely bin fill it with a salt-x solution and put a hose from your tell-tail back into the bin and run it (dont put it in gear, very messy!) let the water temp get to about 55c and turn it off and let it cool, repeat and repeat etc. hopefully that will clean out the engine then use the back-flush method to keep it that way during use.

 

Take the stat out for test purposes only (to prove a point) but put one back in when the problem has been solved as your engine will run to cold and burn more fuel and wear out a lot quicker, they put them in for a reason.

 

Simon L

[Member Removed]

gaffa we run a marina 60hp 4 stroke and last year we had the same prob as you .being on a wet mooring well out it was almost imposible to flush ,and there was long periods betwen useage sometimes. it alarmed just after leaving the moorings,yet we had the tale tale but it was very warm. hearing about salt tex we got the boat to the jetty tok out the thermostat and i trimed the enjine up and put a plastic dustbin over the gear box and lowered it down.i then 1/2 filled the bin with fresh water and a strong mix of salt ex started the engine had very poor tale tale ran till the engine was warm (not long) stopped to cool and then repeated it again and again.after about 3 hours or more we had a good flow. all seemed well .on the next trip just rounded the needles and the alarm sounded again so we anchord fished for a couple of hours and came home on less reves 3500 and got back ok. the boat is now off the mooring . ive been told that it could be the o ring under the power head,or a bad case of internal corrision.and to expect a bill of

[gaffa]

Guys,

As promised update report on the overheating issue.

 

Holes Bay Marine have resolved the problem which was traced to my original theory of corrosion of the waterway causing deformation of the O ring and restricting the water flow to about 30 % of what was needed to cool her at high speed i.e above 4000rpm.

 

 

On contacting EP Barrus they said they had never had this occur on the 115hp model before and as a gesture of good faith would go 50% on parts.

The warranty on the engine was for 2 years but mine was 4.5 years old .

 

To Holes Bay Marines negotiating credit and also due to my advance knowledge of a possible design flaw by reading internet forums. EP Barrrus have now agreed to pay 100% of parts costs of

[Maverick Martin]

Good gesture from Barrus and a result for you. Also well done to Holes Bay Marine former supporters of this club

 

Martin

[Les L.]

same problem as Pete on my 2002 mariner 60hp 4 stroke, well out of warranty but looks like Barrus will do the parts at cost.Engine has been regularly serviced and flushed after each use from new so disappointed it happened.

 

Les

[gaffa]

Les,

 

Sorry to hear about your Mariner problem.

I think flushing will at best only delay the issue and unless they change the component materials to those that don't galvanically react with each other the problem will continue.

 

It will be interesting to see how the 5 year warranty will cope as without flushing there should be a considerable number of claims within this period.

 

They may of course have solved the problem on the newer engines hence being able to provide the 5 year warranty.

 

I hope so because it seeems a simple fix of component materials could solve this issue once and for all.

 

Glad to hear you recovered the parts costs anyway .

Problem is theres still a big labour bill to pay!

[charlieannear]

Well, 75hp Opti Mariner fitted this year with 5 year warranty. Not a 4 stroke and kept on a trailer but I'll let you know how I get on.

Assuming I can get the bloody boat in the water that is!

[Les L.]

Mariner apparantly no longer use the duff component that corrodes and restricts water flow.Dont know when the switch occured but would advise anyone with a 5 year old ish unit to get it looked at. Mine, flushed after every use, had corroded to the point where the guy who replaced it reckoned it was restricting 70% of the water flow.Luckily caught in time so no knock-on damage.

 

Les

[Sinbad]

Pete

If you are on a swinging mooring rather than a pontoon, Ive been using a plastic bin full of fresh water to pump through the engine once I've picked up the mooring.

All you need is some ingenuity with the deck wash pump.

 

Recently, when the engine was serviced, whilst my thermostat was stuck open, the engineer said the cooling water passages arround the cylinder looked nice and clean.

 

I'm sure Rob Francis would have posted if he'd seen this - last year he did a salt X flush of his outboard and took some nice snaps before and after - what a difference!

 

Hope you get it sorted quickly..

 

Paul

[gaffa]

Paul,

My Mariners been sorted for quite a while now and is running like a dream.

 

I'm on a pontoon berth and find it too tricky to carry out a proper flush using the waste bin system and backflushing doesn't get to the parts that matter without taking the thermostat out or at least ensuring its open.

 

If they've revised the design then the problem is resolved on new engines .

 

On my engine which I think was repaired with the previous design of parts I am expecting 4 years more usage without experiencing the problem again.

 

Just to reiterate the problem was deformation of the o ring providing the seal between the power head and gearbox leg through which the cooling water is pumped through the engine and exhausted through the propeller.

This deformation was caused purely by the build up of galvanic corrosion solids .

 

Its a great engine when running to spec.

 

Peteg