trim/tilt

[walleyedan2]

i have a88 85hp force. had overwinter leakage from pump res. base. fixed leak, replaced o rings in valve body. useing non det 30 wt. can not get trim to work unless i push down on motor, recycled at least 15 times.bleeds down on it's own from full up position. when it gets to trim it stops. are the brass washers under large spring to increase down pressure?there is only 1 lg. and 1 small spring in sys. i also could not remove the one poppet valve. any help uot there?

 

[RRitt]

Re: trim/tilt

It is not pressure. 1988 did not have regulated reverse pressure. There is a small spring that allows emergency bypass and that's that. As long as it is somewhere between 200 and 2000 PSI then it is fine. 1987 had regulated down pressure. If your pump had two large springs then it is a 1987 design. Even then it would not cause your problem. If you get springs mixed up then tilt goes up halfway and then runs out of juice.

Your problem could be incorrect assembly, a missing slider in bottom, a still leaky seal somewhere, or god knows what else. Valve bodies are not something that should be taken apart in the average basement. It takes at least 40-50 tries before you really and truly begin to understand the rights and wrongs of doing it. There are at least half dozen variations and every one has its own quirks. So there are no manuals ... if there was then it would be 40-50 pages on just valve bodies because of all the variations. At one time or another Prestolites were used on almost everything that floated. And each one had its own variation.

take it apart reral slowly. draw pictures. take notes. make absolutely certain that you can put every little piece back exactly where it came from.

 

[walleyedan2]

Re: force trim/tilt

Re: force trim/tilt

ok thanks for the partial responce. istill need to know what the brass washers under the large spring do. there is only one large spring and one small spring.i have no external leaks. is there anyone that knows the exact size of the valve o rings. only three dif. size rings.cir. clips hold bottom end together. if the trim &tilt pistons need to be rebuilt where is the best and fastest sorce of parts for those
thanks again


" hook em in the lip"

 

[RRitt]

Re: trim/tilt

the brass shims give minor adjustment to "up" pressure. Put them all back where they came from and it is what it is. I doubt you have a 5000psi pressure gauge anyway to measure pressure. So just put it back the way it was.

you absolutely, positively MUST use stainless retaining rings. If you use plain steel then you will someday pop a plug out into the bottom the lake and be completely S.O.L.

a lot of the parts are still available through mercury for doing your rams. However, if your debris wiper (top of tilt and shock) is stiff or cracking then mercury does not have what you need. The scraper keeps water out. It is a critical seal. Sooner or later I will probably list some seal kits on Ebay that include the wipers. For now, if your wipers are good then you can get what you need from mercury.

don't even ask about a valve body seal kit. No how, no way. Too many possible things that can go wrong and I'd spend all day answering emails.

 

[RRitt]

Re: trim/tilt

i have a88 85hp force. had overwinter leakage from pump res. base. fixed leak, replaced o rings in valve body. useing non det 30 wt. can not get trim to work unless i push down on motor, recycled at least 15 times.bleeds down on it's own from full up position. when it gets to trim it stops. are the brass washers under large spring to increase down pressure?there is only 1 lg. and 1 small spring in sys. i also could not remove the one poppet valve. any help uot there?

ok - thinking about this ....

It is normal for bleed down to stop at trim. Your valve body needs rebuilding.

It is weird that you pushing down on motor makes any difference. Could be anything. Likely suspect is valve body but it could be a problem with trim housing. I have seen where people put their trim back together with the cylinder out of alignment and it cause the system to get stuck halfway down when the piston gets jammed.

You should not mess with the brass shims. Increasing and decreasing the pressure is beyond the scope of a home repair. There is more chance of making things worse than better.

to get the other poppet out you push it from inside. You will need a tool approximately 9/32" in diameter with a cup shape on end. A 3/16" nut driver works if you are careful. If you score the cylinder wall you are SOL. If you mushroom the end of the slider then you are SOL. gently tap the tool and drive out poppet from inside. As long as you don't score, scratch, bend, crack, or drill then the valve body will remain fixable.