60 hp rebuild problem

[fishfeatures]

Hi,

I had to get my 1990 60hp honed after the alarm went off, so i added new rings too. Now my problem is that once the crank case halves are bolted together and the fly wheel lightly, added the motor spins perfect but once the plugs are in it is harder to turn with the compression.
I added oil to the cylinders and hooked up the starter and jumped it directly from the battery,

Without plugs it spins as it should no hassle at all.

With plugs in the flywheel won't turn and the starter sticks. I have also tried a spare reconditioned starter and still the same result. I think the issue is compression related.

Hoping for some help here please guys, I have had it apart twice and can't see anything obvious..

 

[Chinewalker]

Re: 60 hp rebuild problem

Standard bore? Oversize? Did you check the ring end gaps before re-installing the pistons?

 

[fishfeatures]

Re: 60 hp rebuild problem

it was already rebored to 0.30 (not by me but po ) and the ring end gap came within spec..... It spins like a top until the plugs go in.... i can nearly spin it with one finger before i tighten the crank halves together.

 

[Faztbullet]

Re: 60 hp rebuild problem

i can nearly spin it with one finger before i tighten the crank halves together.

Center or top main bearings not aligned...

 

[fishfeatures]

Re: 60 hp rebuild problem

Center or top main bearings not aligned...

They are sitting on the dowel pins, and it turns over freely using two hands when mated together, but once the plugs go in it's is noticably harder to turn over.

I'll strip it again and start from scratch over the weekend and see if that works
Would there be any point in using the old rings in case it's the new ones are causing the trouble.???? can't see how though as the rings were checked for ring gap in their cylinders

 

[fishfeatures]

Re: 60 hp rebuild problem

UPDATE...

well I stripped it down and rebuilt it from scratch yesterday and , and SUCESS!! it lives again..... I must have missed something simple in the 1st attempt that caused the tightness but I still couldn't see anything out of place.


ANyway have to go , I've got 10 hrs of break in time ahead of me.....

 

[durban]

Re: 60 hp rebuild problem

i don't know if you removed the con rods from crankshaft if you did very important you put the bottom half's back with the same rod & the correct way around if not the expect major problems

 

[fishfeatures]

Re: 60 hp rebuild problem

i don't know if you removed the con rods from crankshaft if you did very important you put the bottom half's back with the same rod & the correct way around if not the expect major problems

Made quite sure everything went back in the exact spot it was lifted from.