Alpha 1 Vibrates while turning

[peteua636]

This boat is a 1999 Chaparral 290 Signature Cruiser twin 5.0L and alpha 1 Gen 2 drives. The lower units of the drives have been overhauled last season and by just hand twisting the u-joints without seeing any slop we decided they were ok. I am noticing a vibration more from the starboard side than the port when the outdrives are trimmed up and turning. It is less noticable when the drives are trimmed down and turning but is still evident. Any Ideas??<br /><br />Thanks<br />Pete

 

[Rickles]

Re: Alpha 1 Vibrates while turning

I'd replace the u-joints and check the gimble bearing very closely.What do the splines in the coupler look like?

 

[peteua636]

Re: Alpha 1 Vibrates while turning

I didn't notice anything worn. It had plenty of grease on the yolk when I took it apart. I did spin the gimble and didn't feel anything rough. I did use an alignment tool also seem to go in and out without any trouble...boat only has 135 hours on it.

 

[KRS]

Re: Alpha 1 Vibrates while turning

Follow Rickles advice, check for coupler splines... I did.... I didn't have any left

 

[peteua636]

Re: Alpha 1 Vibrates while turning

was there any evidence of metal shavings when you disassembled?

 

[KRS]

Re: Alpha 1 Vibrates while turning

As for me.. .yes lots of aluminum shavings still on input shaft splines where it spun itself neatly around inside the coupler.... I STILL love my boat, just can't use it right now

 

[peteua636]

Re: Alpha 1 Vibrates while turning

Rickles: <br /><br />Can you physically see faulty U-joints? I did check these and there seemed to be no slop in them.

 

[flashback]

Re: Alpha 1 Vibrates while turning

QUOTE "Can you physically see faulty U-joints? I did check these and there seemed to be no slop in them. " no, I had some that were worn enough to see grooves in the journals on the spyder, but you could not tell it until it was torn down and inspected........

 

[peteua636]

Re: Alpha 1 Vibrates while turning

Thanks....Its coming apart this weekend!!

 

[anesthes]

Re: Alpha 1 Vibrates while turning

I dunno if I've been in a mercruiser boat that didnt vibe a little bit on turn.<br /><br />-- Joe

 

[peteua636]

Re: Alpha 1 Vibrates while turning

Well - hauled the boat out and installed all new u-joints. The old ones looked and felt ok but under the caps there was some minor wear possible flat spots . Alignment was checked and the starboard motor was lifted 3 threads to even out the spline marks made on the alignment tool. Port motor alignment looked good. Gimbals were check by 4 different people one being a mercruiser mechanic and was decided that they were in good shape no roughness binding etc. Checked the coupler for splines it both sides have a square profile to them merc mechanic said they look fine. <br /><br />Drives practically jumped back on the boat. Very easy to install them.(new o-ring and gaskets) Much easier than last time. Walked right on! Verified that the trim extented measurement was 19 3/4" on both drives which is less than the spec. of 23 3/4" per the manual. Left the limit where it was at 19 5/8" center to center.<br /><br /><br />The water test. Got it out on the lake seemed to run ok. But have the vibration/growl noise in the transom when the steering is turned to the stop on the starboard engine in full trim - not as evident when trimmed down. Also when running straight and in a slightly trimmed position have a pulsing style vibration at the transom. Anyone have any ideas? this thing is driving me NUTS...!! Thanks for all the previous replies!!