Surging When Hot - Replaced Carb, Plug, Coil, Air Filter - Video & Pictures

glawnboathead

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  • / Surging When Hot - Replaced Carb, Plug, Coil, Air Filter - Video & Pictures
Hi Folks.

So when my Lawnboy model #10627 gets hot it starts surging. Here is a video of it.

[video]http://vid1114.photobucket.com/albums/k526/GmanBanjo/MVI_5880.mp4[/video]

Here are some pictures of it.
IMG_5881.jpg

IMG_5882.jpg

IMG_5883.jpg


I have replaced the carburator, have good fuel, and good fuel flow.

I have replaced the coil and plug and air filter.

I have tried running it with the gas cap very loose (so no vacuum).

Suggestions? Could it be a auto choke?

Thanks for your advice.
 

bertsmobile1

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  • / Surging When Hot - Replaced Carb, Plug, Coil, Air Filter - Video & Pictures
If it only surges after it gets hot then you are chasing an air leak between the carb and the cylinder.
 

glawnboathead

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  • / Surging When Hot - Replaced Carb, Plug, Coil, Air Filter - Video & Pictures
If it only surges after it gets hot then you are chasing an air leak between the carb and the cylinder.

OK. I will look into that. I did put a new seal on between carb and motor when I replaced the carb. Things did improve somewhat with some of these new parts. It used to not even start after stalling when hot. Now it keeps running until it hits a load, dies, but is easy to start.

Squirt some soap water around the carb to find the leak?
 

lewb

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  • / Surging When Hot - Replaced Carb, Plug, Coil, Air Filter - Video & Pictures
carb cleaner, something that is going to change rpm when it gets into engine, brake cleaner would also work.
 

franchi

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  • / Surging When Hot - Replaced Carb, Plug, Coil, Air Filter - Video & Pictures
Hi:

Is your float height set the correct amount? It may be a bit too low!

This sounds like a fuel problem. I had a similar problem with a 4 cycle engine. I replaced the carb with a new one, but the problem remained. I called the factory and their expert told me to drill the main jet with a certain letter drill. End of problem! Both carbs were made with the main jet too small.

Call LB and speak to a tech! Your surging sounds like it is too often to be a fuel problem. Usually a surging problem is not that rapid. Could it be something in the spark advance? I had a problem with the spark advance in a LB two stroke engine that caused the engine not to speed up to running speed after starting. It started easily but would not rev up to full speed. I found that the automatic spark advance was faulty. Replaced ignition module, $24.00, and all was well.

Keep us posted as to what you find.

Good luck,

Franchi
 
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