Identifying piston bore on 90 Evinrude

[gr8rg8r]

I am having the block on my 1988 Evinrude 90 cleaned and honed. The machine shop wants to know what the bore is of the current pistons and I can't find any markings on the pistons. Where would the markings on an OEM Evinrude piston be to indicate if it is .00 or .010 or .020 etc.? They are just under 3.5" in diameter according to my micrometer. There is a "0" on the underside of the piston but no markings on the top of the piston where the machine shop guy said they would be.

Thanks in advance

 

[mikesea]

Re: Identifying piston bore on 90 Evinrude

you have the 3.50 bore that is standard,if it was oversized it woud have the oversise stamped on the top,it wouldnt have oversize unless rebuilt,if you have a manuel it tells you,you can also look on the iboat store to shop for the over size pistons and necessay parts