Mercruiser trim problems

Hi I am having problems with m

Hi I am having problems with my trim on 1975 mercruiser. The trim will go up but not down. The motor runs but wont go down. I have took apart the pump and everything looked good to me. Also about a week ago I went to start getting my boat ready for the season and tried the trim and it went down but know it won't go down. Motor still runs. Hoping someone can help me. Thanks Jon

"This is the service man for a

"This is the service man for an oildyne trim pump. The problem mybe in the solinoid (sp) or in the hose that enables the return. Remove one (1) trim ram from the frnt of the drive, have someone raise and lower the drive to see if that ram is working in the up/down motion. If so, replace it back on the drive and do the same thing to the other trim ram. If one rame moves up and down the motor is OK. If the both move in the up motion only chech the down solinoid to see if it is operational. You may find it in the service man that I listed.Another thing you may try is to remove the down and up line on the trim cycilder and see if you can manually compress the trim ram. If it is stuck and you cant compress it down, then the trim cylinder may be defective. The trim pump is self venting so dont worry about letting air in the system. Also there is a section in the service manual that tells how you can bleed the system if this is an air issue. Best of luck.

http://www.boatfix.com/merc/Servmanl/6/6A5R3.PDF"

Up pressure is 2200-2600 down

Up pressure is 2200-2600 down is only 400-600. Your trim cylinders are probably frozen. Sometimes a large person standing on the drive while attempting to lower may free them up. Not the fix. They need to be replaced or rebuilt.

I had the same problem. I ende

I had the same problem. I ended up having a bad trim cylinder. It was bypassing internally. Unhook the cylinders from the drive raise the drive. when you push down they will either go down equally or not. typically the slow cylinder is the bad one.

I bought a new style trim pump

I bought a new style trim pump that plugs right in to the original harness. It works twice as fast and is 110% better. Just screw it down to the floor and plug it in.