Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

1995 Toro Powerlite 38170 5913399 with a Briggs HSK600 1680S (0) 42221

 There was low power on this so I opened it up.  Confusing was all the holes in the bore.  There are about 7 holes.  Theey are mostly on 1/2 of the bore arc and low so probalby intake and exhaust ports but weird there are so many.  There are 2 small holes opposite and strange.  One is low and one very high.  What are the two small holes for?

The bore is smooth but I'm not just how bad the piston and rings are.   The top had a fairly thick coating of carbon.   Anything look obvious about the condition of the piston?  There's blowby stain in the piston but I'm not sure if it indicates anything.  The piston skirt is not scored.

Are you sure that's an HSK600?   If it is, that's a Tecumseh engine.   I've got two HSK850s on a couple SS snow blowers.   Great little engines but quite a bit different from the HSK600.   

The two small holes are probably for the decompression system.   One of my two cycle motorcycles has a similarly small hole above the exhaust port for decompression. 

 I'd clean everything up, lightly hone the cylinder to get the glaze off of it and put in a set of new rings.  Be very careful putting the needle bearings for the bottom end back in.  Use some thick grease to hold them in when re-assembling.