I have a '13 GDSD with 450 hours. The lower unit was replaced under warranty around 100 hours. I'm hearing a metal popping noise from the lower unit or belt housing area. The popping noise is more frequent if I add weight to the boat. When it first started making the noise it would only do it when running wide open, but now it does it at low rpms too. It sounds like a bushing or bearing going bad to me, but I don't know where to start to figure out what needs replacing. I'm trying to avoid taking it to the dealer because I would have to wait about a month for it to get fixed. I took the belt housing and lower unit covers off and made sure that everything was tight and listened to the bearings and universal joint with a stethoscope and they sounded fine. It will only make the popping noise under a load. Any ideas on where to start?

I would suspect U joints if it changes with load. if you pull the covers and grab the prop and rotate it one way and the other can you feel anything moving that shouldn't?

Everything sounded and looked fine when spinning the prop a full rotation either way. There is a cunt hair of play when slightly pulling the prop from left to right or vice versa.

I forgot to mention in my original post that I have also noticed that the motor jerks a little bit and vibrates when running more than it did before this started.


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If everything rotates smoothly and doesn't bind I would take it apart and check each part separately. Like I said before, I would suspect the U joints.

Might not hurt to pull the belt off and make sure you don't have some play going on with the crankshaft. Check the up/down play and thrust as well. Then check the lower unit separately.

Okay, I just priced out the whole u-joint assembly with GD. Coco is going to call me when he gets in to make sure that's what I need. That whole assembly was replaced in February of last year, but I've put about 200 hours on it since then. Appreciate the advice.


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