wayer getting in ??

[tunnels]

Can water get into the bottom 2 cylinders of a 115 hp v4 1988( its a 25 inch shaft and along way out of the water) and if so why and how does it happen and what can be done to fix the problem ??
Started missing at just over 6000 rpms ,gradually cleared its self after a few minutes at a slow speed ,around 1000 rpms

Big motor, small boat so going to have the fast stop screw reset to 5500 rpms by the local marine shop as well as a total service and check over !

[jb123]

most common is a bad head gasket

[tunnels]

The motor runs perfect ! starts easy !no hesitation when you push the lever !
smooths as !clean plugs !
The guy in boat place said it happens and they had a 1990 that had done the same thing but worse ! He said Blame is pointed to a exhaust restriction in the bottom housing where the prop is .

[jb123]

if the plugs are clean....how are you seeing water in the cylinders

[tunnels]

if the plugs are clean....how are you seeing water in the cylinders

Am just saying what i was told by the guy at the outboard repair workshop . It just happened all of a sudden at just over 6 grand on the tacho and after a short time gradually cleared its self I have never been that high again just to 5500 and was ok .
He said it only happens at high rpm ,sounded strange to me, i have clocked up a few hours since and all is fine, have kept to 5000 and not gone over .

The hole for the speed o in the leading edge of the leg is blocked so have no idea what speed im doing .
Its a 115hp on a 14 foot boat running a 13.5 dia x 19 pitch so its getting along at a few knots !

[boats.net]

The rev limiter is set at about 6200 rpm's on that motor and that may be the miss. If it is water getting into cylinders then could be a head gasket, a hole corroded through cylinder head or exhaust plate. I have seen rear livewells overfull and splashing out water at high speeds spraying water on engine which would be sucked into intake of engine.

[tunnels]

The rev limiter is set at about 6200 rpm's on that motor and that may be the miss. If it is water getting into cylinders then could be a head gasket, a hole corroded through cylinder head or exhaust plate. I have seen rear livewells overfull and splashing out water at high speeds spraying water on engine which would be sucked into intake of engine.

We have had the most fantastic weather so have been out fishing every day , The motor has not missed a beat once since the first time i used it .Have been checking the plugs each time i go out and come back and they all look the same . Going to get the rev limit set to 5200 or close to that .Motor is going in for a complete check over charging , float levels , oil delivery , and all the other things they do . Going to up the prop from 19 pitch to 21 just for a try out .Not going to worry about it till its had a look over !
Thanks for every ones input !.
I hear what you are saying about water from an outside source but the motor is way away from the water all the time ,its the reason i changed the transom from a 20 inch to a 25 for this very reason .The splash well never gets any water in it at any time so far . Don't have a drain any where in the hull just a big volume bilge pump with a pipe that goes straight out the back .

[tunnels]

Water getting into cylinders !!

Today i found the answer to my own question .
The power head is bolted to the mid section and the exhaust goes down through there into the muffler . where the exhaust exits The casting can be thin in that area and it corrodes from the inside to where the exhaust goes out . Hence suction from the exhaust and this can and does draw water into the 2 lower cylinders on the block , Mainly the port side as it is the lower of the 2 on a V4 .
This can be repaired by getting welded , built up and then filed flat and reassembled with new gaskets .
If you have a look an a service manual in the spark plug section there is a explanation on the tell tale signs of how to tell if moisture is getting into a cylinder .
I don't like not knowing what the causes are of a problem and if i find the answer i like to share !
Yahoooo !!