Re: mercruiser alpha 1 question
I had just bought my boat, 1987 Invader 18 ft bowrider w/ 4.3 merc. and Alpha one gen one, and took it out a few times. It seemed strange that, when turning to either side, I could here a slight rumbling noise throughout the hull. Well, not knowing much about boats at the time, I didn't think much of it. I took her up to around 30mph and trimmed up. When I got back to the ramp, there was a bad vibration around the engine/ oudrive area. Took the boat home, pulled the plugs, and ran a compression test. It had 180 psi on all cylinders and very clean plugs. I put on the muffs and started up with the drive trimmed down. The vibration was not as bad, so I trimmed up a hair and it seemed to get worse. Time to pull the outdrive. I didn't see any leaks in the U-joint bellows, but there was water and some rust inside. The bearing seemed rough, but the U-joints seemed to move freely with no slack. I replaced the bearing and decided to replace the U-joints anyway since I was there. BTW, I did find a much easier way than what the manual says. When I took the U-joints apart, the needle bearings had very dirty grease. One U-joint cup was bone dry. It was a good thing I decided to do them even though they felt fine. My very long explanation has a point. If you are there, replace them anyway. You never know what you might find once the cups come off.