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cham783
04-09-2007, 05:37 PM
I have a 92 Boomerang with a PCM 1:1 transmission. I am getting a knocking noise coming from the transmission area when I put the boat in gear. No noise when its in neutral but when I put it in gear at idle it starts knocking. When I rev the throttle the noise seems to pretty much go away. It does it in forward and reverse.

Any ideas on what this could be?

MOOMBA_97
04-09-2007, 07:13 PM
Mine did that only at idle though. Check the strut bushing/bearing.

cham783
04-09-2007, 10:00 PM
The strut bushing? Where exactly would I find it?

h2oskierrick
04-09-2007, 10:02 PM
I have a 92 Boomerang with a PCM 1:1 transmission. I am getting a knocking noise coming from the transmission area when I put the boat in gear. No noise when its in neutral but when I put it in gear at idle it starts knocking. When I rev the throttle the noise seems to pretty much go away. It does it in forward and reverse.

Any ideas on what this could be?

Hey Cham,
It's most likely your dampner plate. This is where the transmission input shaft connects to the back of the engine. These are designed to take up the vibrations from the engine at idle and to absorb the shock of going into gear. When the springs get worn they cannot absorb the vibration and that is the noise you most likely hear. This needs to fixed soon or the vibration will cause the pump bearing to migrate messing up the pump, bearing, and seals. The noise goes away above idle because the hub is forced against the plate. Easy fix if you only have to replace the dampner.(stillhave to pulllthe transmission) Hope you caught it early.

How do I know? similar experience on my 87 Nautique, hope this helps.

cham783
04-10-2007, 07:45 AM
Oh boy - fun fun fun. I can't wait to pull that trans out again!

The dampner plate, is that part of the transmission or the thing inside the bell housing where the shaft connects to the engine?

I haven't run it except in the yard so hopefully it hasn't done any other damage.

Thanks for the help.

Engine Nut
04-10-2007, 09:38 PM
Oh boy - fun fun fun. I can't wait to pull that trans out again!

The dampner plate, is that part of the transmission or the thing inside the bell housing where the shaft connects to the engine?

I haven't run it except in the yard so hopefully it hasn't done any other damage.

Thanks for the help.

If you are just running it in your yard, out of the water with no load on the prop there may not be a problem at all. Put it in the water and check it again. With no load on the prop, the springs in the drive plate do not get compressed and things can get a little noisy.

Engine Nut