Tricky Trim Pump Fail.
TikiHut2
Member Posts: 1,431 ✭✭✭✭✭
While wrapping up the stern drive oil change in the shop and doing a general once-over in the engine compartment I went to lower the OD and noticed an odd high pitched squeal when the trim pump engaged and runs. The drive tilted up fine but now the drive won't lower even though the solenoid clicks and the pump is running (but with a slight squeal). Plenty of oil in the reservoir, it just won't retract the rams.
Any input welcome. Thanks Mike
Any input welcome. Thanks Mike
2004 FV270, 300hp 5.7 350mag MPI Merc 305hrs, 2:20 Bravo3 OD w.22p props, 12v Lenco tabs, Kohler 5kw genset, A/C, etc.etc...
Regular weekender, Trailer stored indoors, M/V TikiHut, Sarasota, Fl
Comments
(Sterndrive.com LINK)
The last linked theory about trim senders possibly being screwed up sorta sounded familiar because the trailer switch on the throttle lifted the drive but the same trim switch function only causes a pump sound but no retraction action. Thanks, Mike
The evening update and youtube video to watch (TRIM PUMP VID LINK) .
Tore out the pump and the pump seemed fine to me except for the slight squeal on the down command and a a sputtering amount of oil that was coming from the down port with both hoses disconnected. It may have been simply sucking air from the up port but thats all I have to go on. It has plenty of fresh clean oil and the lower screens in the pump looked brand new with no debris or water.
Could it be a bad ram or a some sort of other issue besides a bad trim pump? I'd hate to sink some serious money into a new pump only to realize it's a problem in a line, a ram, or something that someone later said oh yeah it was that other thing. With twenty something views I'm hoping somebody has an epiphany. On the other hand maybe it's just a bad pump.
Thanks for any insight. Mike
The stanchions get grabby sometimes, and drag crap past the seals is why I commented that.. I've no experience in trim hydraulics, but have seen it in other applications.. when it does that, even if the debris only hang for a little bit under the seal, crap can get in, or oil can get out.. going down needs good volume, going up needs good pump, right? I'm thinking going down is when you would discover a good sized leak.. I could be wrong, though.
Im missing something but not sure what the trick is. Hope I dont have to resort to guessing with new parts.
Thanks again. Mike
Anybody know if there's a particular process needed to purge any air out of the system during re-assembly? Thanks. Mike
Sounds like a stuck check valve, the pump (old ones anyway) run the same direction and you
are just changing the flow direction to the rams sounds like the valve is stuck on the down circuit
not allowing flow which is why the pump squeals as it is making pressure but is not flowing.
I don't know if you can remove or service the check valves. My experience is with my old
Merc pump on my outboard. Someone else may know if there is a manual release valve on the pump that will let you move the lower unit up and down by hand. I've not been that involved with
my new ride to know about the newer pumps.
Looks like Aero and others had it right about it being sticky on the up side. After refreshing the whole pump and lubing everything(including the ram seal and joints) overnight I recruited some help to push down on the drive while I operated the switch and it now operates up/down just fine.
Even though I opened the system I didn't need to bleed the air out either. Seems that unless a ram is rebuilt, these trim pumps will self prime pretty well. Also, I had replaced a "down" relay 6mths ago and the "up" one seems temperamental so my advice would be to replace them both if one gets glitchy.
Hope the details help someone else down the line. Now it's on to the next item on my off-season punch list. Thanks again for the trim pump input. Mike