I have an 89 Formula with a 7.4L and a bravo II. I changed all the drive oil and engine oil during the winter. I took it out for the first time this summer and the boat is making some kind of funny noise. It sounds like the engine is working too hard to turn the prop. It is not a vibration more like a shaft in a bind. The noise is very constant, not like a valve knocking or something like that. It is almost like I can hear a gear in the outdrive turning. I looked at the drive oil and it looks good (no metal) The noise is not noticable at idle or below about 1200 rpm after that it starts to become noticable. I can still run at higher RPM but it just doesn't sound right. I have had the boat for about 3 years and I know there is something not right. If anyone has any suggestions I would appreciate it. Not a good way to start the summer :-(

Sounds like gimbal bearing (water in u-joint bellows that sat for a while).

Could it be the gimble bearing. I had a bad gimble bearing one time and at idle it was fine but once the rpms got up I would hear like a friction grinding rumbling sound going through the whole boat.

Those are the two things I have thought of. I have a feeling it could possibly be the U joints. I have had to run in some shallow water lately and I have a feeling I may have been triming the drive up to much. I hear that really tears up the U joints. I think next weekend I will take the drive off and take a look-see. Any other suggestions would be greatly appreciated.

I hate Bravo's

Just to let you guys know....

I took the outdrive off and apart. One of the two U joints had a little rust on it so I replaced it. I eventually took the top of the outdrive apart and found some metal particals. The roller bearing had started to eat itself up. For some reason the roller pins started to chew into the part of the bearing that holds them in place. It messed up the bearings and the races. Replaced the bearing and the races and cleaned all the other bearings out and seems to be running fine now. I have no idea what could have caused that bearing to start to go like that. Thanks for all the advice!

Improper preload on the bearings. I opened up a brand new bravo once to check something and found the preload on the timken bearings was 10 times higher than it was supposed to be. However, youve had it for 3 years, if it was the preload, youd think it would have let go before this.

Formula 31,

That is exactly what I think. I checked the book for the preload on the nut and it is a very low number. I can't remember exactly what it is but I have a feeling that it might have been tightened to tightly. The nut was hard to get off even with a foot long socket wrench. The boat sat for a four month span for the first time since I have owned it. No matter what maintence you do there is no replacement for running it on a consistent basis. Hopefully that will be the end of the troubles for the year.