what damage can be done to an over heated marine engine

• #ane

Hi all

I have a Betamarine 20hp engine fitted to my boat and was using the calm conditions today to exercise some mooring techniques when the engine temperature alarm started to sound. I speedily stuck the gunkhole in the nearest empty pontoon berth and shut the engine downward. Afterward opening the engine compartment I was expecting lots of steam or something merely all seemed well although I could tell that the engine was hot. Beginning port of telephone call was the strainer - this was completely stuffed total of bright green weed. I cleared this then checked the impeller which appeared to be fine. After leaving the engine for about x minutes I fired her upward and all appeared well as it was after running for a farther half an hr.

I'm non sure at what betoken the engine alarm goes off - my merely experience is with car engines that sometimes when 'cooked' are never quite the same once more. Does anyone know if I am I likely to have caused some long term damage to the engine or does the temp warning go off before this happens? I think I may exist investing in an exhaust temperature alarm that would have alerted me to the problem probably quite a bit earlier

Thanks

<60 minutes width=100% size=i>Gavin

• #ii

Yous are joking, aren't you? The alert is then that yous DONT damage the engine. It worked. You reacted immediately. The cause was obvious. One time stock-still it worked perfectly.

Surely there must be something worse to worry about on your boat. If non, so y'all are very lucky.

Diesels are remarkably tolerant. I seized mine final year when the impellor broke up and I didn't notice.; it just stopped and wouldn't turn over. Took me half an hr to change the impellor, by which time the engine had cooled enough to unseize and restart, evidently none the worse for wear.

- Nick

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• #3

cliff

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Mine did the same twice due to loss of coolant. Alarm goes off - terminate the engine and find out why.

The alert in xx hp beta goes off at around 115 deg C at which indicate you nonetheless take coolant (50/50 glycol/water) in the engine water jacket and exchanger. This mix will non boil off until around 125 degC so plenty of margin to stop the engine and fix the problem. BTY the sensor in located in the exchanger and so you are reading exchanger temp.

All I would exercise is drain the coolant and replace with fresh l/50 mix of glycol and water to ensure the proper mix is maintained. The glycol non but acts equally a corrosion inhibiter / antifreeze simply raises the boiling point of the coolant. DO Not EXCEED 50/50 - too much glycol will rot the rubber bits.

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• #iv

Equally previous posts, you have saved any meaning damage to your engine. I too seized a Bukh through lack of oil many years ago. I booked the mechanic to take it to $.25, but he just turned the flywheel backwards and the engine unseized. It lived for several years, though was used a lot oil subsequenlty.

What you lot might look at, if the water inlet was blocked, is the mixing box where the h2o cools the exhaust. These are often made of plastic, Without the cooling h2o the plastic might melt, and break the exhaust organisation. This might fill the engine compartment with fumes, and it allows water (when you lot fix the blockage) to fill the engine compartment. (done that also!)

Give the system a skillful check out.

Regards

Mark Johnson

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• #5

Although a flake abrupt in his reply webcraft is absolutuly correct in the mechanical part of his respond. The alert organisation is designed to forbid any harm and as you'due south works properly all volition be well. Not everyone understands mechanics, nor should they need to and those of us who do can sometimes exist a little intolerent of others. I'1000 certain yous have a forte.
Use your engine with confidence and continue upwardly the practising. Might be very useful
one day.

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• #6

Cheers to everyone for their replys - yous've certainly put my listen at remainder.

My cognition of marine engines is limited to servicing and general maintenance equally per the manual although I am trying to expand this and did remove the engine this winter with a friends aid to replace the engine mounts. I didn't have whatever information regarding what indicate the overheat alarm goes off but now I practice I'm much happier nearly what happened.

Regards

<hr width=100% size=ane>Gavin

• #vii

Re: vacuum alarm

agree with this.

But besides every bit a temperature alarm (which measurest hat the coolant is as well hot) it would not be a bad thought to have a vacuum alarm - which would show that the pressure of the inlet coolant was too high cos of a blockage or summink - and which would then lead to overheat.

20hp engine is not reallt gonna have a probleem with a bit of overheating. Supertuned hig-revving petrol engine mostly certainly could be busted tho with overheating.

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• #8

As others say, the engine warning is there to save the engine. The commonest fault is a blocked inlet, but dumped coolant (especially from a estrus exchange organization) and a failed pump are also mutual.

If the engine was running for a while with restricted cooling water information technology is just possible to exercise impairment to the exhaust hose, even though the engine is fine. Typically this is separation of the inner function of the pipage from the outer, so superficially it looks OK. If there is whatsoever loss of power as y'all open the throttle next time, undo and check the hose particularly where it commencement leaves the engine.

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• #9

Aja

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Joined

6 November 2001

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When I fitted my new engine a couple of years agone I was advised to fit the type of anti-syphon valve which gives a small discharge from the valve.

I put this on the stern and now just have to glance to see what the water stream is like. I tin tell if at that place is weed in the strainer if the water catamenia is less than it should be. It is non a replacement for an exhaust temp alarm but a neat indication that water is flowing through the engine.

Donald

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• #x

Donald - I retrieve I have this kind of valve fitted equally information technology is piped into a small tee in the frazzle pipe. This is near the exit which is an underwater skin plumbing fixtures hence I have no idea if water is flowing through the engine.

I estimate I could connect this to an higher up water transom fitting instead to give me an idea that water is indeed flowing.

Cheers

<hr width=100% size=1>Gavin

• #11

Aja

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Joined

half-dozen Nov 2001

Messages

4,275

Careful. There are 2 types - both fabricated by Vetus. One is as yous describe which takes water afterward the inlet pump and goes up over the highest point in the engine (and above the h2o-line) to an anti-syphon valve and so the water goes back down to the exhast manifold where it joins the frazzle proper.

The type I accept has this gear up also - in addition there is a pocket-size outlet from the anti-syphon valve with a piping leading to a small-scale peel fitting - in my situation on the transom.

Hope I have described this ok. I dont retrieve you can lead the 1st type to a skin fitting. I could exist wrong....

Donald

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