Gearbox slipping

[Bradleybez]

Good day all

Im having troubles with my dads old 55 Yamaha, revently the seals let go on the box and the bearings colapsed, we fixed all of this and put it back together, now when we use the boat, the minute the motor comes under load it seems like the prop is slipping, but its a brand new prop, any help would be great thanks.

Bradley

[TownsendsFJR1300]

With the engine OFF and in GEAR, can you spin the prop?

Do your clicking coming from inside the case or is the rubber prop insert spinning?

I'm assuming upon re-assembly of the LU, all gear lash spec's were correct and adjusted if needed?

[renegaderob]

With the engine OFF and in GEAR, can you spin the prop?

Do your clicking coming from inside the case or is the rubber prop insert spinning?

I'm assuming upon re-assembly of the LU, all gear lash spec's were correct and adjusted if needed?

I have same . have noise inside LU in gear on muffs.prop bush seems ok .no obvious wobble prop .I do have small dent on prop been their a while only started to play up last trip 1/4 pwr at prop

[TownsendsFJR1300]

I have same . have noise inside LU in gear on muffs.prop bush seems ok .no obvious wobble prop .I do have small dent on prop been their a while only started to play up last trip 1/4 pwr at prop

Can you describe the noise in better detail (grinding, knocking, etc) or better yet, record it and up load to "You Tube" if its audible enough(over the engine noise)?


Just curious, aluminum or SS prop?

With the dent on the prop, obviously something was hit.

IMO, and easy enough, I would pull the prop and check run out (any wobble on the shaft), a dial indicator even better.

Then, just for S&G's, just by hand,[B] push / pull the shaft sideways and check for ANY SIDEWAYS PLAY. It should be tight. The same as what your checking with the dial gauge.

Draining the LU oil into a VERY CLEAN container and checking for ANY METAL particles can easily let you know if theres major issues going on inside as well.

*I asked about the SS prop only as that prop is harder to bend than aluminum and will transfer any impact force much more so than an aluminum prop to the lower unit.

[renegaderob]

Scott thanks for reply alloy prop , no sideways movement , no metal particles Have since taken to Yamaha dealer tested in tank couldn't find any issues . I have doubts. So next chance I get will test under load . They tried to tell me heat issues were one possibility but pumps plenty of pressure and was same from start.

[renegaderob]

Scott thanks for reply alloy prop , no sideways movement , no metal particles Have since taken to Yamaha dealer tested in tank couldn't find any issues . I have doubts. So next chance I get will test under load . They tried to tell me heat issues were one possibility but pumps plenty of pressure and was same from start.

Also will check on muffs again soon as it stops raining.

[TownsendsFJR1300]

I'm wondering if indeed its not sliping and you may have other issues with the engine.

When you put it under load, is the engine revving faster and the boat is NOT ACCELERATING?

If you can take a video/audio of its performance on the water, UNDER LOAD, that would help a bunch...