skirt clearence

[demitche]

I am in the process of boring out my 70hp Johnson and the tech wants to know the skirt clearence. The original cylinders are 3' and the pistons I have are 20 over. He has the ring gap and the piston with him but I cannot find the skirt clearence he is aking for. I do not have a manual. The year of the motor is in the range of 76 to 85 it shows the motor on the I boat web site.
Any help would be greatly appreciated.

 

[a70eliminator]

Re: skirt clearence

Piston to cylinder clearance is measured at the skirt, the books just call it piston to cylinder clearance, it's usually about .004 max but you'll have to find your exact spec. surely it's in the clearance charts.