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
-Robert