Logo
FULL SITE MENU

outdrive wont stay trimmed up under load

R

Rscottdds

Regular Contributor
I have an SAE J1171 Marine pump with a sump reservoir for my trim. It will work on the trailer (go up and down and stay up) but when underway it wont hold trim and slowly drops to full down. The pump is attached to a Volvo Penta 290 outdrive but I have been told this pump is usually on Mercruisers. How should I trouble shoot this issue? Any hints on how to fix it?
-Robert
 
Rscottdds said:
I have an SAE J1171 Marine pump with a sump reservoir for my trim. It will work on the trailer (go up and down and stay up) but when underway it wont hold trim and slowly drops to full down. The pump is attached to a Volvo Penta 290 outdrive but I have been told this pump is usually on Mercruisers. How should I trouble shoot this issue? Any hints on how to fix it?
-Robert
Click to expand...

I noticed my Mercruiser has a bypass circuit with a small manual valve to let you move the drive if the pump fails. If this were open, leaking or defective the prop thrust might push it down??
 
The SAE J1171 merely means it’s compliant with the Society of American Engineers specification for marine electric motors. Without knowing the specific trim pump you have it’s difficult to say what the fix could be. However all trim pumps have a valve body of some type to control the flow of hydraulic fluid. Yours is probably dirty inside and that’s keeping one or more valves from operating properly. I’d look for a good used one as it’s not really cost effective to try to repair these things. A new replacement is hundreds and hundreds of dollars so get a cheap one from eBay or your local boat recyclers.
 
If the piston rings leak, you won't see any oil loss and the drive won't stay up. By the time the piston rings wears to the point where it leaks, there is probably wear on the cylinder itself. It's not like these were made to industrial standards.
Replace the rams and be done with it.
 
what does the fluid in the pump's reservoir look like?

And have you had to add any oil to it??? if that answer's no, then Capt Bob pointed you in the right direction...
 
I never did get around to addressing the tilt issue in the offseason. Life got in the way :). I did take her out this weekend and when I am underway the gauge reads -6 after running for a few minutes. When I stop it goes back to -5. I can't get it to read -6 unless I am under load. Is this still probably a ram issue? Is there any long term issues running it like this for the season?
-Robert
 
Back
Top