Mercury 500 labyrinth seals mushroomed

[spunkymonky]

I wonder if anyone could tell me the cause of the labyrinth rings mushrooming in the reed block. I don't want to spend $160 on a new one if the same thing is just going to happen right away again. I would assume the crankshaft has to much sideways play in it but why. Should I change out the main cap needle bearings just to be sure and if so should I also change the outer race?

 

[Laddies]

Re: Mercury 500 labyrinth seals mushroomed

That's crankshaft wobble caused by a bad main bearing or bearings

 

[Faztbullet]

Re: Mercury 500 labyrinth seals mushroomed

Good call Laddies, also check the prop pitch as I have seen engines under propped and excessive rpm cause ths due to crank flex...

 

[spunkymonky]

Re: Mercury 500 labyrinth seals mushroomed

Thanks for the input. Are there any specs on what the Main bearing crankshaft journal should be or should changing the main bearing outer race and needle bearings cure the wobble?

 

[Faztbullet]

Re: Mercury 500 labyrinth seals mushroomed

top ball brg journal.......1.180
center main journal...... .984
mains........................1.000
bottom main............1.180

 

[spunkymonky]

Re: Mercury 500 labyrinth seals mushroomed

Thanks Faztbullet. Where do you find those specs as the Mercury manual tells you nothing of that?
I measured the crank and all journals were exactly the same as the numbers you posted or slightly over by .0005. So I guess the problem lies in the bearings. I did measure the ID of the labyrinth seals and they measured .989 on the good one and .995 on the one that is mushroomed.
Anyone have a used in good shape reed block