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I just bought my first bricktop . It's a lawn boy 7024 . I'm going to give a compression test and would like to know how much compression these old bricktops should have ?
 

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For accurate readings when checking compression on a small two stroke like a Lawn Boy, find a compression gauge that has a Schrader valve (tire valve) right in the end that screws into the spark plug hole.
 

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Mines not a brick tops but my;

F - 130psi.
D409 - 60psi (ring gap was .075 - both rings) just bought used :sidelaugh
 

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Mines not a brick tops but my;

F - 130psi.
D409 - 60psi (ring gap was .075 - both rings) just bought used :sidelaugh
That is outstanding compression for ring end gaps of .075 on your D series, I think you may need a .030 over piston for that cylinder. LOL I have a few worn out cylinders that I woud like to do that with...but I only have one .030 over piston though.

Your F series has outstanding compression to, about 125 psi. is the best I have seen from any of mine.
 

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Mines not a brick tops but my;

F - 130psi.
D409 - 60psi (ring gap was .075 - both rings) just bought used :sidelaugh
I assumed that the ring end gap was checked with new rings, but I think you were checking with the old rings, so yeah with new rings that compression should be great.
 

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I assumed that the ring end gap was checked with new rings, but I think you were checking with the old rings, so yeah with new rings that compression should be great.
I didn't check the 'F's' ring end gap, the compression was so good I didn't open it up - just cut the lawn with it. This one was a garbage day find..

The D409 I just bought and it wouldn't start even with gas in the plug hole so I dug out the compression tester. The farther I dug in the worse it got until I measured the massive ring gap then I started laughing :sidelaugh I'm waiting till Tuesday for my new rings to arrive, then I'll test again.
 
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