Anyone have luck rebuilding a trim pump on a 290sp

"my outdrive is sagging on my

"my outdrive is sagging on my 290sp drive with the aq151a 4cyl, it will not stay up overnight, or it will not hold a trim while driving, I don't see any leaks but i did have to add oil once this spring. is their anyway to test what is bad, the pump or the cyl's. when it is in the up position i can not push it down but it will fall over time, and when driving it will not hold a position at all i have to adjust every few minutes. this has the pump with no resevoir, it is a all in one unit, I have found that their could be check valves that leak is this something I can clean?? has anyone tried this or taken one apart?"

"well after some playing last

"well after some playing last night here is what I found. Ire moved the pump and tried to dissasemble it with no luck, you need some special torx sockets which I did not have, I just cleaned it up and put it back. when i rais the outdrive it will basically stall the pump when it gets to the full up position. but when i go down it will hit the down position and continue to pump the no problems 9of course the drive will not move. also just how do you fill the pump? in the up or down position? I filled it in the up position, then when it was down if I remove the fill screw it blows lots of pressure out of the pump, so i assume you must fill with the drive in the down position? with this info can anyone say for sure if it is the pump or cycl's bad? the cyls are bone dry no leaks, you can not push the drive down but in 30 minutes it will settle on it's own. I guess I can try to reverse the oil lines and probably test the cyl's right? if I reverse the 2 oil lines it should go down when i press the up buttons and stall the pump if the cycls are good, Right? or will the position sensor not let it work???"

"Jschick you are not alone, I&

"Jschick you are not alone, I'm diligently waiting for someone come up with some good advice on tilt/trim leak issue you described. I just pulled my boat out of the water because of the same problems although I had very slight leakage in and around the pump, and when I removed the front cap, not the top, the oil showed that it had been contaminated with water. I show that there are no external leaks anywhere on the outdrive. Is your oil clean??
I viewed another thread that stated that some fixes can be as easy as replacing an O-ring in the top of the pump. I will try to open the pump and find this O-ring tomorrow night and report back......."

"I understand Your frustration

"I understand Your frustration about theese issues, and unfortunately I may only add to it. Both pumps and cylinders are repairable without to big problems, provided there are no severe corrosion dammages. But the main problem is there are no 'official' supplier of spare parts around, not repair manuals generally available, not tools and specifications. I Used to repair quite a number of different kinds, both Penta, Mercruiser, OMC etc, but had contact with people that could get me the small parts needed: In the air craft industry! A lot of theese pumps have their origin from that area. Unfortunately, should I try to explain to each and one how to fix the different problems on the net, I would bee to buisy. Remember this board activity we do for the fun, to help and without 'warranty' and time guaranties and free of charge.
The tip I may give is to find an air craft mech used to the hydralic systems, he might be able to fix and get the parts, probably from exchanged units as they are mostly not allowed to dismantle them, but they are perfect spare part source for Your needs!
If You feel up to it, take it all appart, it is possible, but You will get very few hints and tips back from different board when it comes to hydraulic issues like trim/tilt and power steering. That is maynly for us 'screwd up' people that have refused the manufacturers statement:not repairable!
What has been put together, must be able to take apart, and someone must have produced the parts inside. Sorry, but that is Your problem.
The positive thing, when you find the problem, the actual repair cost in parts is normally only a few cents compared to new units for xxx$!Perhaps that is the reason parts are not officially available: PROFIT!"

"Gents, I will add my <[img]"h

"Gents, I will add my

The Seloc manual has a chapter dedicated to tilt and trim. It states that when the stern dirve will not hold in the raised position, the hoses are to be inspected for leakages (correct as necessary) and also it could be due to faulty trim cylinders, in which case the o-rings in the cylinders may be damaged and leaking. There is a section in the manual that covers how to replace the o-rings.

Personally, I feel that any owner of a boat with a Volvo Penta engine or sterndrive who wishes to conduct his own repairs should get hold of a copy of the Seloc or Clymer manuals (or both) for their power plant and consult the relevant chapters when they have a problem. They would save themselves a lot of frustration."

"my oil is clean, and the cyls

"my oil is clean, and the cyls are dry, so i assume the cyls are good, the pump is a bit damp but you can't trace any leak. can anyone confirm the 2 oil lines, is one for up and one for down, or is one for one cyl and one for the other cyl? if one is for up and one for down then I should be able to swap the lines, which would reverse the opperation on the switch and pump which i would think would be a good test for the cyls??? currently in the full up position the pump will stall, but down it will not, so if i can reverse the opperation of the pump and it stalls in the down position then that would cnfirm it is the pump not the cyls. or if it still stalls on the up then it would be a leaky cyl?? but to do this i need to know how the pump and lines run, one to each cyl or is one for up and one for down, and then they must Y off to the 2 cyls???"

"I don't think you underst

"I don't think you understood my message. If the trim cylinders are dry (I assume you mean there are no visible external oil leaks) the problem may be the o-ring in the piston (that is, inside the cylinder) being defective and causing an internal oil leak. If this is the case, once you lift the outdrive, the oil will pass from the bottom side of the cylinder (which is pressurized) to the ram side of the cylinder (where there should be no pressure) through the defective piston o-ring due to the weight of the outdrive resting on the rams. It would be the same effect as experiencing blow-by gas in an engine's crankcase due to defective piston rings.

My suggestion is that you you should take the trim cylindres apart and rebuild them, then take it from there."

"If You really want to 'kn

"If You really want to 'know' what and why You are doing things, get a manual, get two pressure meters, hook them to the pump, check pressure from pump and if pump holds the pressure. If ok, cylinders are 'bad'. O-rings/seals or shock valves."

"thanks,

i understand the c

"thanks,

i understand the cyls and such, but was just looking for a way to test them on the boat. to confirm if it is the pump or the cyls. I guess one simple way would be to just raise the motor and plug the oil lines with a 10 cent fitting. if it still drops then it is deffinatly the cyls, if it stays up then it is the check valves in the pump.. or one could remove the lines from the pump and put in 2 plugs right at the pump and see if it stalls. simple and takes less them 10 minutes...."

"Not too uncommon to get dirt

"Not too uncommon to get dirt in the valves on the trim pump, thereby causing leaking valves.
Remove pump, clean out with compressed air. Reinstall and try. You remove the air out of the system by raising/lowering the drive repeatadly. Fill oil as needed.
I'd try this first since it is MUCH easier than going after the trim/lift cylinders in trouble shooting."