# Lawnboy 10247



## Rentahusband (Aug 25, 2008)

Mower will not start. Compression is 110psi, have spark, carb is clean. Do I need to check the reed valves??
Thanks.


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## 30yearTech (Sep 14, 2006)

It's possible that there may be some debris stuck under one of the reeds. You should be able to see them, with the carburetor removed. Another thing to check is the top and bottom crankshaft seals, this engine should have retainers to keep them in place, but if not, they sometimes come out of the crankcase. Make sure there is noting plugging up the muffler or exhaust.


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## Rentahusband (Aug 25, 2008)

Thanks 30 year!!


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## penguineman (Apr 15, 2009)

I was gonna say check the exhaust ports & make sure there not all carboned up


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## Rentahusband (Aug 25, 2008)

Could be. The oil mixture looked quite dark.


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## Rentahusband (Aug 25, 2008)

Turned out to be the top seal. I reinstalled it, ran fine but popped out within a few minutes of running. I picked up a new seal. There is a groove in the block that looks like a retainer ring should be there but no diagram lists one for the top seal. Should I be using loctite or something to lock the seal???
Thanks


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## 30yearTech (Sep 14, 2006)

Here's the deal, the seals on this engine are really meant to be installed when the crankcase is split and not pressed into when assembled. They are clamped in place by the crankcase halves. 

I have never had much luck keeping them in place without splitting the crankcase and installing them this way. Locktite might work I have never tried as they are supposed to be installed with no sealant around the seal.


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## Rentahusband (Aug 25, 2008)

Thanks 30year.


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## Rentahusband (Aug 25, 2008)

Split the crankcase and installed new seal. Works great. 
Thanks again 30year!!


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## Rentahusband (Aug 25, 2008)

Spoke to soon. Seal popped out again, so I found a retainer ring. After running it for a bit, it started making the same popping noises and quit running. Seal was still in place. Any other suggestions??
Thanks


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## geogrubb (Jul 28, 2006)

Rentahusband said:


> Spoke to soon. Seal popped out again, so I found a retainer ring. After running it for a bit, it started making the same popping noises and quit running. Seal was still in place. Any other suggestions??
> Thanks


What popping noise, I didn't see anything about popping noise in the previous posts. Have a good one. Geo


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## 30yearTech (Sep 14, 2006)

Under no load, some 2 cycles like to pop every once in awhile. If it seems excessive, I would try a different spark plug.


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## usmcgrunt (Sep 16, 2007)

I have never worked on a lawn boy,so this is just an uneducated guess.If the seal is not sealed well in the crankcase,I would think you are not developing enough vacuum to draw in the fuel mix and creating a very lean condition due to the air leak.I would try a bead of rtv around the seal before installing it.Two cycles are pretty fussy about compression and vacuum being correct.


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## geogrubb (Jul 28, 2006)

30yearTech said:


> Under no load, some 2 cycles like to pop every once in awhile. If it seems excessive, I would try a different spark plug.


That must be between the zing, ding ding and blubber, however I do not have a 6.5 Duraforce so am not familar with their sound. I love LB, the F engine is amazing for it's "rated" 4hp. Have a good one. Geo


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## Rentahusband (Aug 25, 2008)

I do understand the normal noises of a 2 cycle. This is not normal. The popping noises occured just before the seal popped out, along with some puffs of smoke. After I installed the retainer clip, it did run a bit longer before making the same noises/puffs of smoke as when the seal popped out and would not start again. Going to reassemble and ckeck for spark if it happens again. The seal is staying in place with the retainer ring. 
Thank You for your comments. Any others would be appreciated!


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## Rentahusband (Aug 25, 2008)

Is it possible that the lower seal is failing when the mower is at operating temp?? Runs fine till is gets warmed up. Has spark when it acts up.


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## Rentahusband (Aug 25, 2008)

Replaced the plug and NOW it works fine.


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## 30yearTech (Sep 14, 2006)

Rentahusband said:


> Replaced the plug and NOW it works fine.


Sometimes it's the simple things. 

Glad you got it figured out... :thumbsup:


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## Rentahusband (Aug 25, 2008)

I figured if it had spark when it was acting up the plug was fine. Apparently not. Yep, sometimes it is the simple things. 
Thanks again.:thumbsup:


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