1997 120Hp Force one cylinder not working?

[swick]

Re: 1997 120Hp Force one cylinder not working?

Are you running the motor on muffs and getting all this water in it or is the boat in the water when you are running it?

 

[onthechip]

Re: 1997 120Hp Force one cylinder not working?

Are you running the motor on muffs and getting all this water in it or is the boat in the water when you are running it?

Mostly on the muffs, but I first noticed the problem while on the lake a few weeks ago and I just had it out for a ride this past weekend.

 

[swick]

Re: 1997 120Hp Force one cylinder not working?

The reason I ask is so we can try to eliminate possible points of entry as far as the water goes. You've already eliminated the possibilty of fuel contamination, so now we have to consider all of your seals. If you are getting water in while just using muffs then that eliminates water entering the block from the outside somewhere (like when you are gettine on plane), but we should be able to follow the water path from the muffs up the proper channels to check for failures. I still have my engine sitting on my work bench so I'll put some more thought into it and see if I can come up with anything a little later.

 

[onthechip]

Re: 1997 120Hp Force one cylinder not working?

The reason I ask is so we can try to eliminate possible points of entry as far as the water goes. You've already eliminated the possibilty of fuel contamination, so now we have to consider all of your seals. If you are getting water in while just using muffs then that eliminates water entering the block from the outside somewhere (like when you are gettine on plane), but we should be able to follow the water path from the muffs up the proper channels to check for failures. I still have my engine sitting on my work bench so I'll put some more thought into it and see if I can come up with anything a little later.

I greatly appreciate it! Anything other than a cracked block would be nice.
Underneath the powerhead, there are the adapter plate and gaskets, under that is the exhaust plate gasket. Can water get in there?

 

[swick]

Re: 1997 120Hp Force one cylinder not working?



This is what the bottom of the engine looks like with the adapter plate removed. I really don't see how water would be getting in from anywhere around the adapter plate, unless your block itself were not sealed.

 

[onthechip]

Re: 1997 120Hp Force one cylinder not working?

View attachment 146705

This is what the bottom of the engine looks like with the adapter plate removed. I really don't see how water would be getting in from anywhere around the adapter plate, unless your block itself were not sealed.

After thinking about it a little,...I'm with you on this one. If one of those gaskets failed, the only path for water to get to the cylinder is through the exhaust chamber. If that was happening the water would just get blown out the exhaust, I'm guessing?? If that's not true and the water did get sucked back up into the powerhead, then why would it only get sucked into the #3 cylinder? That doesn't make much sense...
I hope to have time to work on the motor this weekend. I'll dig a little deeper and see what I can see.
Thanks,

 

[pnwboat]

Re: 1997 120Hp Force one cylinder not working?

However the water is getting into that cylinder, it doesn't look like it's due to any of the usual failures (head gasket, exhaust cover/baffle).

Years ago I had a similar problem with a motor only it was #1 cylinder. Had a marine machine shop check the block for cracks. Could not find any. Tried having the head gasket sealing surface on the block re-machined to true it up. Had the head itself machined to true it up. Nothing fixed it. Finally I replace the block. Got a used block and switched everything over and that fixed the problem.

Not saying that this is the problem in your situation, but whatever it is, it's something unusual.

 

[swick]

Re: 1997 120Hp Force one cylinder not working?

Pnw, ouch! What did you wind up doing with that block after all the $ you put into it? I hope you were able to get something for it somewhere.

Onthechip, I wonder if when your crank cover was installed the RTV failed around the #3 cylinder? Thats really the only thing I can think of other than having an unusual defect somewhere. Either that or the head itself could be slightly warped at #3. It doesn't take much to let water in, especially at the rate and pressure its being pumped in.

 

[pnwboat]

Re: 1997 120Hp Force one cylinder not working?

I still have the block sitting on a shelf in my shop. One of these days I might really give it a close look. I have an idea where the leak might be, but it'll take some doing to check it out. I know the owner of the machine shop so we just traded work. It just cost me several hours installing a Digital Read Out on one of his metal lathes in his shop.

 

[chuck palmer]

Re: 1997 120Hp Force one cylinder not working?

I would take a close look at the bolt holes on the block side of the motor, I had a block that had a crack in that area. What I did was to fill in the hole with a metal epoxy and used a set of centering sleeves and redrilled it and taped it and the motor has run now for three years with no problems.

 

[onthechip]

Re: 1997 120Hp Force one cylinder not working?

Thanks to all of you for your help!
I found one of the Reed petals broken. A new set of Boyesen Reeds and the motor runs great, no more dead cylinder, no more water...

 

[pnwboat]

Re: 1997 120Hp Force one cylinder not working?

Glad you got that one figured out!

 

[SnooKer420]

Re: 1997 120Hp Force one cylinder not working?

Hi guys. Im new to the forum. I found this thread on google, because i am having the exact same problems with my 1997 force, only it is the top cylinder. I Was trying all the same fixes for a dead cylinder with spark etc etc etc. After finding this thread last night this morning i pulled off the carb and WOW there is a broken reed petal. This has been an amazing help. Just curious as to how you finaly diagnosed the problem. Is it also possible that there is actually no water in the affected cylinder and the milky look is due to the cylinder cycling and not firing putting super fine bubbles (like foam) in the gas oil mix. Just a thought.

 

[matyc423]

Thank you! So glad I found this thread! Was having the same symptoms one cylinder not firing. Pulled off the carbs and indeed I have a few broken reed petals.