8252 has bright spark, clean carb, etc.. won't start!

[peteclark3]

Hey guys,

We have a Lawn Boy 8252 that used to run like a champ. It started running so-so, so we did a couple of things.. put in a new spark plug, sanded the points, checked all the connections, took apart and cleaned out the carb, put in fresh gas, and replaced the crank seal. When I put it all back together, I could get it to fire once or twice, even once I got it running at a low RPM, then it stalled. Same with starting fluid, just a fire or two. After a bit of sitting (week or two), and a re-clean of the carb, and new gas again, I can't get it to fire at all, even with starting fluid sprayed in the cylinder, and sprayed in the carb.

What's crazy is that the spark is bright blue.. so I thought it'd fire at least once given that I sprayed a bit of fluid in the cylinder... oh well.. any help would be appreciated! Miss this mower running well like it used to...

 

[turfboy1997]

check the compression too. i had an m series that i did an overhaul on and the rings were weak and it only had 70 ish psi. I had a extra engine that had great compression so i stole the piston and rings out of it and put it the engine and it started up. but eventually the coil stopped working on it too. I replaced that and it runs like a champ now. I think if the compression gets too low it can cause it to run weak or not at all. Since it was running well and then it didnt run at all i dont know if this is it, but just an idea of something to check. good luck!

 

[Rivets]

Did you check or change the crank seal under the flywheel? This seal had a tendency to dry out and then pop out.

 

[robinb66]

yep sounds like you getting air into the system somehow check your seals and the carb gasket, as well as the reed plate to crankcase seal!!

 

[turfboy1997]

also make sure that the reed plate is flat against the housing. over time a gap can form causing the engine to not run right.

 

[peteclark3]

Oops, I didn't realize I had a thread started on this. I'll delete the other post. I checked compression and it's 75 psi, which I think is enough to start.. could the spark be sparking at the wrong time? Or if the timing was off would it just not spark at all?

 

[peteclark3]

Sorry to bump but this mower is still sitting in my garage waiting to be reassembled pending advice from anyone willing to help. Could someone answer my question about the spark timing from the previous post?

 

[turfboy1997]

Sorry to bump but this mower is still sitting in my garage waiting to be reassembled pending advice from anyone willing to help. Could someone answer my question about the spark timing from the previous post?

check the flywheel key and see if it is sheared. check the carb throttle spring and make sure it is working correctly.

 

[peteclark3]

check the flywheel key and see if it is sheared. check the carb throttle spring and make sure it is working correctly.

Will do, but the spark question.. Does the fact that it has spark mean that it should fire from an electrical perspective? Or could the spark be sparking at the wrong time? Just want to know if I can check the electrical system off the troubleshooting list..

 

[lunytune2]

electrical is good