Expert: Everett Peacock - 7/7/2010

Question
QUESTION: I have a alpha one, circa 1996, and it is having problems with trim and tilt. If you press the button there is a high pitch whine, like the relief valve is being tripped and the lower unit does not move. If you tap the button the unit will move a little bit. There is oil in the reservoir, the electronics seem fine. Have a repair manual, but do not have a good diagram of the relief valve. Is there a good diagram available? My dad and brother-in-law think they can fix this while the brother-in-law is in town. Or is Mercruiser one of those that you have to buy a new pump and not parts to rework the existing one? Right now we are not sure we can get the lower unit up enough to get it out of the lake when the brother in law leaves his rental cabin. The boat docks are about 2 weeks behind and I have no where to store the boat on the lake waiting for a mechanic. Thanks for any advice.

ANSWER: one of your trim cylinders have gone bad..

---------- FOLLOW-UP ----------

QUESTION: Thanks, my brother-in-law writes this: Could it be the by pass valve?  When I bump the up button I can actually raise the lower unit, but it takes a long time and a lot of "bumps"?  Also, once I got the lower unit showing to be about 1/4+ of the way up I left it there and it is holding there.

Answer
the relief valves inthe pump do not really go bad...what happens is on of the trim cylinders has a broken o-ring in, letting the fluid pressure try to work against each other...with the boat out the water, remove the trim rods from the drive.. now use the trim aqnd watch the cylinders... the one that doesn't work is bad...  that is the only test i know of with out a trim pressure gauge..