Help with resurrecting old Lawnboy 2 cycle

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  #1  
Old 04-05-04, 10:38 AM
951Tom
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Help with resurrecting old Lawnboy 2 cycle

Decided to try and resurrect my 1976 Lawnboy mower model #5273. When I turn the flywheel by hand it feels like it's got good compression and I hear air whistling thru the carb... but when I put a compression tester on it, I got 30psi cold. I'm waiting on a new pull cord assembly so I can't see if it will run. Does this compression sound too low? Been stored for about 13 years but I did drain the gas so the carb looked good but I still cleaned it. Thanks.
 
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  #2  
Old 04-05-04, 08:13 PM
Terminator20's Avatar
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While you are waiting for your recoil rope, check to see if you have spark. If you don't have spark, the engine won't run of course.
 
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Old 04-06-04, 12:19 AM
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Hello 951Tom!

It sounds like you'll need to clean or change the reed valves. If you hear air coming out the carb, and only have 30psi on a compression test, they are probably dirty/bad.

I agree about checking for spark.
 
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Old 04-06-04, 07:45 AM
951Tom
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Spark is strong and a nice blue color after replacing the plug wire. I did the compression test with the carb removed and installed...I got the same results. Do you think a new piston and ring kit will improve compression? If so, can I just install the piston without doing anything to the cylinder wall? The reeds looked ok and were still pressing flat against the reed plate but I will replace them since they are a few bucks. I have a steep hill to mow and this mower is super light weight due to a 19 inch magnesium deck, so I'd love to get it running. Thanks for the replies, I appreciate it.
 
  #5  
Old 04-06-04, 10:53 PM
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Sounds like low compression to me, but give it a try. The reason I suggest this is because the rings may be stuck from sitting up so long. If you can get it started and warmed up, the rings may well loosen up and seal again. If not, you'll need to look at the piston and cylinder wall to tell whether or not anything will need to be done to them.

I just thought of this...lawnboys, especially the ones with the muffler under the mower deck, were bad about clogging the exhaust ports. This will show a false low compression reading. Check it out and see.
 
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