7.4 mpi bravo 3 clunk

Gkicker13

New Member
Jun 4, 2019
3
Boat Info
1999 Sea Ray 270 Sundancer
7.4l MPI Bravo 3
Engines
7.4 mpi bravo 3
So I am new to the forums here but have been using some of the posts as guides over the years. Have a problem i cant solve and was hoping someone else could provide some input.

7.4l MPI with bravo drive is clunking when in neutral. It still is clunking in drive but its less noticeable. Pulled the drive, checked alignment and pulled upper covers off. All looked clean. No metal in the drive oil either. Ran the boat with no drive and it sounded good with no vibration. Gimbal is smooth and the u joint dont seem to have any sloppiness to them. So im thinking either the coupler (which i would think would be slipping) or u joints and im a bad judge of them. Anything else to look at?

Sorry for the long first post but im getting pretty desperate as the season isnt too long here on in Northeast Ohio. Thanks for any insight you can provide.
 
When you refer to "drive", did you check for it in both directions? Almost sounds like an issue with shift linkage or the cone clutch itself. If not fully engaged or disengaged it can give a clunking when trying to grab or hold. A weak or damaged spring in the clutch assembly would be more than likely only noticeable in one direction.
 
I ran in both forward and reverse, in neutral it makes the same sound but is more noticeable than when in forward or reverse. I was playing with the ujoints and the one closest to the drive has a very slight movement to it side to side. Barely noticeable. The one nearest the spindle has no side to side at all.
 
The u-joints typically produce more of a 'knocking' sound rather than a clunk (it would be relative to rpm/shaft span, as well... and may be more pronounced at the extreme steering angles). And there certainly shouldn't be anything in neutral unless motor mounts/gimble/u-joints are bad (aside from a gear issue, as mentioned).

You're not running the engine with the drive trimmed up high, are you?
 
There should be no side play in the universal joints. Another thing you could check is for up and down play with the leg itself. If the steering lever is corroded or loose on the upper steering pin, the drive can drop which would also cause shaft misalignment.
 
So the drive is trimmed all the way down and the noise is consistent no matter the direction of the steering wheel.

Thornton, are you referring to the steering lever near the gimbal housing? I had that replaced 4 years ago due to water intrusion. The mechanical cut a piece out of the top of the housing to get to it and covered it with a plate screwed and epoxied to cover it. Is there a different way to inspect the lever?

Thanks for all the feedback.
 
Yes. The upper steering pin. The hole that was cut, was to access a thin nut on the upper pin that sets the height of the drive. If it backs off, the drive will drop and cause shaft misalignment. If you have your boat on a trailer, you can lower the leg and check if the outdrive has any up and down play in the steering pins. Might be a possibility for why your clunk/knock is more noticeable in neutral than in gear. Was thinking the loaded driveline (in gear) just may hold the outdrive up, closer to where it should be and reduce the noise you are hearing.
 

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