How does water get in the Clyinders ?

[Skigekco]

Hi, need some advise please I have a 1997 4.3GL VP I/B fitted to a Wellcraft 175 excel. On a recent trip I had a fuel leak problem and ended up getting a tow (without the engining running) back to the habour (safest thing to do).

I sorted the fuel problem out and the engine started fine however after about an hours cruising it became very lumpy and keep on stalling. I got back to habour on very low revs. Whilst inspecting the engine I found I had quite a lot of water in the clyinders. Removed this, replaced the plugs and the coil as this was badly corroded, she started first turn. Can someone explain how water could have got into the clyinders please.

 

[bnicov]

Re: How does water get in the Clyinders ?

Did it diesel after you shut it down??? It could have sucked water in that way. Otherwise, you may have a crack in your engine block or cylinder head. Keep an eye on your engine oil the next time you are out. If it is milky, you have major problems.

 

[Maclin]

Re: How does water get in the Clyinders ?

Water gets into the top of the cylinder thru an open valve. This is usually an exhaust valve that is open when the engine stops, and the exhaust manifold or riser gasketing or component is leaking down to that open valve. It is usually not an intake valve as there is not as readily available water source as there is on the exhaust side.

Water coming back up thru the exhaust can happen if the risers are not high enough in comparison to the positon of the water line of the boat. I suppose if you shoved the boat backwards hard enough it could force water back up that way, but usually the water is already up to the water line in the exhaust pipes and wave action is just not that active where the leg is down in the water.

 

[Skigekco]

Re: How does water get in the Clyinders ?

Did it diesel after you shut it down??? It could have sucked water in that way. Otherwise, you may have a crack in your engine block or cylinder head. Keep an eye on your engine oil the next time you are out. If it is milky, you have major problems.

Hi thanks for taking the time to respond.

Sorry I dont understand the term 'diesel' ?
Re the oil. It looks good no emulsified water present so i don't think its a cracked block/head.

Has anyone go a schematic of the exhaust riser on this engine so I can picture what might of happened. Thanks

 

[bnicov]

Re: How does water get in the Clyinders ?

Dieseling is what happens with carbureted gasoline engines sometimes when they are shut down they continue to 'chug' for a few seconds.

 

[Maclin]

Re: How does water get in the Clyinders ?

The exhaust manifolds have two passages. One for the spent exhaust gases to flow thru and one for the spent cooling water to flow thru. You will see a hose from the raw water system going to each exhaust manifold. The cooling water is routed up to the riser where it meets the exhaust gases. If the riser or manifold or gasketing is compromised then water can leak into the exhaust passage and right into an open exhaust valve.