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Discussion Starter #1
I am working on a lawn boy DuraForce that won’t start.
I have good spark, 90 psi on the compression and fuel.
I did a leak down test and it is leaking 35% out the exhaust.
I assume stuck rings or broken rings but have you heard of the high of compression with that high of leakage?

Thanks,
Bob O
 

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This is a new one to me. How do you do a leakdown test on a 2 cycle? Pressure test yes, leakdown test no. Can you look in exhaust port and see any scoring on the cylinder walls? 90psi is not a lot of compression for a 2 cycle engine.
 

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Discussion Starter #3 (Edited)
I put the piston at top of its travel and locked the blade into position. Then I did a leakdown test which I guess just tested the rings as it turns out.

Lawn boy says 80 psi is the low limit on compression.

I will be pulling it apart tonight to get a better look at whats inside.
 

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Discussion Starter #5
I pulled the head found a scuff mark and metal bits embedded in the combustion chamber along with a good size chunk. I wouldn't think this is normal so unless they want to tear it apart I may never know, I hope they want to tear into it or scrap it so I can find out.

Thanks,
Bob
 

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It seems when LB went to the DuraForce 2 cycle, so went the durability! The old LB's built by OMC would last forever(now someone is going to tell me the durafore is made by omc). If the bearings aren't frozen and nothing is cracked it will run. You will find, if you take it apart, the chunk you found is part of a ring. Have a good one. Geo
 

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Discussion Starter #9
Geogrubb,

Do you think the ring caught on the edge of one of the ports and do you see this often?
I agree about the older LB, we had one growing up that ran forever.
 

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I think(and that's scary) the ring cracked probably from someone trying to clean the mower while it was still hot(done mowing, in a hurry, got to clean it up, sprayed it down) and the cracked ring caught on a port, as you suggested. If it is the 6.5 hp 2-cycle it is one awsome little mower when they are running right. Of course the muffler under the deck "LB Burble" is hard to beat. Have a good one. Geo
 

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Discussion Starter #12
Well, they went and purchased a new mower and gave me this one. Once I get a couple of things done I will be into this one.
Yes it is a 6.5 2 cycle, I have one just like it for my own personal use and now may be two. :)
 
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