boatman747

My #4 speedmasters keep creeping down . No signs of any leakage . When im haulin as- thru the bay one drive will fall 3 clicks on the gage . Any tips for troubleshooting ?

Coolerman

Sounds like your trim pump is just about done. You may need to rebuild it. We went through the same deal.

woody1

I agree on the pump, mine was doing the same thing, overnight it would fall from all the way trimmed up, to laying on the ground

boatman747

Bam has new pumps for $375.00 . Easy fix ? Both sides do the same thing .

Lofty

It could be a pump or a pump check valve. Could also be a leaky cylinder. They have check valves also. The check valves can get debris stuck in them and they'll leak down. Sometimes you can get away with backflushing.

Lofty

Yeah, I would swap pumps before running out and replacing one. Best to isolate the problem first, then buy parts.

Lmarth

It could be a number of things. It's not clear from your post whether it's one drooping drive or both. Assuming it's just one, have you checked the fluid level with the drive all the way in? I assume you have the all black Oildyne/ Kiekhaefer trim pump with the little, plastic, vented dipstick (reminder- you tighten the dipstick and then back it off one turn to expose the vent slot in the side of the dipstick when you're done). If you ran it low on fluid you'll have air in the system which usually self purges by running the drive up/down. Sometime you do have to bleed at the cylinders. The Merc manual very clearly states that you run the drive up and then press down on the lower unit. If the ram moves more than 1/8" into the cylinder, then you have air in the system. It could also be the trim pump. Do the drives go up/down at the same speed and sound the same? I replaced one on my #5's last summer. They can be rebuilt. I'm purposely keeping this brief and its tough troubleshooting without being there. I don't have the Service Manual in front of me but what's been posted on this thread so far should get you started. There are a number of drive hydraulics experts here on OSO that might chime in. Let us know what you find.

Darkspoilerzx

Does it have internal or external return line trim cylinders on it? quick check for the cylinders is to run it all the way down take off the up lines and hit the down button if oil comes out the up port youhave an internal leak in the cylinder.. Ed

Mbam

What Ed said, if you have early #4 cylinders it is very common for the shock piston to loosen up and leak.