I recently took an engine into inventory that came w/o a recoil shroud. As such, I do not have the model, type and code numbers. By the overall look of the engine it appears to be a 1960's-1970's -era 3HP:
1. The piston (standard bore) and stroke measurements match a 3HP.
2. There is an "8" embossed into the top left corner of the cylinder head.
3. Points/condenser ignition.
4. "Pulsa-Jet" carb/tank.
Would this make it a Model 81202?
What surprised me was that the bore has a steel sleeve- which is a FIRST for me. In addition, the top of the piston has a "L" embossed into it, which, according to the Briggs repair manual indicates it is a tin-plated piston (like it supposed to have) in a sleeved engine. The bore is not scored, well within specs, and even has some (very faint) cross hatching still visible in some areas. In addition, the ring gaps indicate some wear, however, still within specs. Crankpin, crank journals, and matching bore holes in the block and sidecover are all within specs.
Here is my question: How much piston scoring is allowable, and when is it too much and time to replace the piston?
1. Approx 50% of the piston skirt circumference has fine scoring, and some of which you can catch a fingernail into.
2. There is scuffing over most of the piston skirt.
I am guessing that the engine had been previously ran with a dirty air filter, or no filter at all. The dirty air caused the piston to score rather than the bore as the former is the softer aluminum, while the latter is the harder steel.
Michael