A couple Lawn Boy questions

viperv10

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Hi guys.
I just bought three non running lawn boys for $30. My wife thought I was crazy. I mainly bought them because I needed a deck for a L21ZPN. All three are F engines and there should be plenty of spare parts there for my other mowers.
The guy told me that one engine didn't have any compression. I was wandering if it was normal to find mushed up oily grass inside the the reed plates? I can't think how all that grass got in there unless they ran it with no air filter.This is my first time opening up a F engine. Another question is can you check for compression on a lawn boy without the carburetor on it? Also what is a good product to use to get some carbon loose on the top of the cylinder by the spark plug hole? I would send some pictures but I don't know how. I don't even have a cell phone.
Thanks for any help.
Jerry
 

jp1961

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Hi Jerry,

No, it's not normal to find grass in the reed valves, don't use compressed air to clean them, it will bend the reeds. You're likely correct in the engine being run without a filter or a damaged one.

It's possible the engine with no compression has the rings stuck due to carbon. G.M. top engine cleaner works great at removing carbon (available at any G.M. dealer). It's also possible the cylinder is scored or simply worn out.

Yes, you should be able to check compression without the carb on.

Regards

Jeff
 

viperv10

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Thanks for the reply Jeff.
I couldn't believe all that burnt up grass in the engine behind the reed valves. The cylinder had one line of rough aluminum about an inch long in it. I wet sanded it down pretty smooth. The cylinder head had a little carbon build up but not bad. I'm going to take it to an old Amish small engine repairman a few miles from here to see if it can be saved with a little honing and a new piston. Like I said Iv'e never taken an engine apart before. I know in theory how everything works but have never rebuilt one myself. I'm 63 years old and am going to need a new hobby to keep me busy after I retire. I'm in no hurry on this one because I have several other good running Lawn Boys. My favorite 2 are a 7073 and L21ZPN. They have the light steel decks and push easier than my aluminum deck mowers.
Thanks again.
Jerry
 

jp1961

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Hi Jerry,

I'd use Loctite when reassembling the engine. 2 strokes vibrate a lot and you don't want any bolts coming loose.

Regards

Jeff
 
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