Re: 89Force 125HP Tilt and trim bleeding off....
The check valve seals are bad, cost about 6.00 located in the pump housing, a search of this site should locate the Merc part number and photo of valve.
yup, almost certainly the check valves. In some literature they may be referred to as manual release plugs. You can buy the valve from mercury. I think the part number is F17620. You will need two of them along with a #11 oring for slider piston. However, I think they are more like $60 each than $6.
I am not sure what to say about DIY. It is very possible to get a cheap and easy fix. But I think it's equally likely to mess up your pump. Whatever you do, don't remove the bolts holding together the two halves. If it gets to that point then send your pump off for professional rebuild. The other "don't do that" is to use the wrong retaining rings. You want 9/16" stainless steel. The slider piston is not replaceable. If one of your plugs pops out and the slider piston goes to bottom of lake with it then your pump is pretty much ruined.
and here is the test.
1) raise your engine & block into place.
2) Take tube that leads to bottom of tilt ram loose from pump.
3) Cap off the tube using 3/16" inverterted flare fittings from any NAPA.
4) Remove engine blocking and observe.
If engine drifts down then tilt ram is bad.
If engine stays up then either pump or trim cylinder is bad.
If color of trim fluid is red then it is a gamble but probably the pump.
If fluid is not red then it is almost certainly pump. trim ram almost never fails unless the fluid is ATF
