I'm new to iboats.com and new to boating in general. I bought a "project" and hopefully haven't bit off more than I can chew. Its a 1992 Thunder Craft 177 bowrider and the engine and outdrive is a Mercruiser 165 inline 6. The best I can gather the outdrive is pre 1975 since it doesn't have the trim senders on either side of the gimbal. Serial 4185664. Not really sure how such an old assembly ended up in a later boat. My current problem (there are several, so I'll be on here a lot) when I raise the lower unit using the trim up it comes all the way up fine. No trailering button, just a 3 wire micro switch up and down. After maxing out at the top, it drifts back down on its own. I thought maybe internal leaking cylinders since the boat sat dormant for several years before I got it. I rebuilt both cylinders with new seal kits. They looked pretty good on the inside. After getting it all put back together it seems better but still drifts down. Not as fast though. I can push down on the drive and make it settle faster. My next step is to remove the trim pump. I'm guessing there has to be a check valve or holding valve somewhere in the pump to hold the pressure. What am I looking for and is it serviceable? I'm sure this topic has been discussed before and I searched through a few threads but didn't find anything. I have enjoyed reading some of the forums though. Very informative. Thank you in advance for any help you can offer.
