Volvo 290a vibration at low speed? Not Gimble or U-joints

Mike VH.

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Joined
Dec 30, 2016
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2
First time poster so please be gentle if Im asking a dumb question. The boat is a twin set up so there are two 290a drives and Aq151b engines. The one side is smooth the other has a vibration/ growl at low Rpm only when in gear. Ive spent a lot of time reading on this topic and have check everything Ive read about that could be an issue that ive found but that doesnt mean I havent missed other post.

Ive taken both drives off because they both had some water in the oil and Im doing a complete reseal on both. I was hopping to find something obvious when i did this after reading a ton of posts.

This is what I know so far, the gimble bearings and seals look good in both and have no movement, the u-joints also look good no rust and feel good. All the bearings in the upper trans look and feel good with no play and the backlash feels about right havent put dial on it yet though. The lower bearings on the prop shafts feel good too. I check the shaft on the outdrive that had the noise before i took it out and it was with in a .001 of turning true, but when I pulled the outer cover to change the shaft seal there was major seal wear on the shaft so Im going to replace it. The center shaft has the same amount of play in both drives side to side and up and down with the center case removed from the lower. This is the only bearing thats had play and Im wondering if this could be the problem and or how much play should be in this shaft both in the lower needle bearins and also in the upper bearing just below the the tapered bearing?

Drives are both apart and can take pics or check anything that may need to be done. Thanks for your help.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Joined
Jul 23, 2011
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51,234
There are no gimble bearings on a 290, so not sure what you checked. You could have a failing PDS bearing. Check the U-joints
 

Mike VH.

Recruit
Joined
Dec 30, 2016
Messages
2
I thought the gimble bearing was the bearing at the very back of the bell housing where the the engine side of the ujoint shaft hooks up. Thats the bearing I checked an there is no play there.

What is the PDS bearing and where is i located?
 
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