krypto 1 in CT

at about 2000 to 3000 rpms just before getting on plane or doing low speed turn around at about 25mph the boat is getting a nasty shake.it dosnt do it going slow out of the harbor or up on plane.it dosnt feel like its the motor.feels more like a universal joint or the prop hub somthing after the coupler.any ideas?.i think im going to pull the outdrive and check the u joints.any other ideas out there before i take it off.i checked the motor mounts and the out drive bolts there all good and the prop nut is tight.its a pretty nasty shake it feels like if you got on the gas while its shaking somthing would break.

RLW

Check the U-jounts VERY carefully for a missing bearing cup retainer clip and slightly backed-out bearing cup. Also, carefully check the gimble bearing. If it's the least bit loose or rough, then it's time to change it. And there should be absolutely NO evidence of water in that bellows cavity.

krypto 1 in CT

thanks for the reply.im going to pull of the outdrive this week to check it out.ill probably just replace the gimble bearing and u joints while its off.any other ideas out there on what it can be?.if the motor wasnt aligned right would it make this type of shake?.i noticed there is no ajustment for the motor height.it has the merc off shore motor mount set up and i dont see how you can adjust it unless you use washers or somthing?.ill check the alignment while the out drive is off hopfully i wont have to mess with any adjustments.looks like they got the motor adjusted and welded the 2 sections together where you would be able to make adjustments with through bolts but now its 1 solid piece.