190cc Briggs Backfires when warm

[Sten4413]

Hello,

I have a 190cc B&S lawn mower engine that starts and runs great. After the engine is warm and I go to restart it, i get a backfire. I almost positive its out of the exhaust/muffler. If I pull start it again, it runs great.

What are some things I can check.

 

[mechanic mark]

b&s 190cc engine backfires when starting with engine warm - Google Search

 

[bertsmobile1]

As a push mower engine is stopping unburned fuel is pumped into the muffler where it very slowly dissapates
When you pull the starter the hot / burning exhaustignites this gas in the muffler which causes a pressure wave pushing the piston down when it is trying to go up.
Second pull has no unburned gas in the muffler so off it goes
You may have a partially blocked exit hole due to mud wasps building there over winter .

 

[Sten4413]

As a push mower engine is stopping unburned fuel is pumped into the muffler where it very slowly dissapates
When you pull the starter the hot / burning exhaustignites this gas in the muffler which causes a pressure wave pushing the piston down when it is trying to go up.
Second pull has no unburned gas in the muffler so off it goes
You may have a partially blocked exit hole due to mud wasps building there over winter .

I check the exhaust, valves, gas, cleaned the carb and good spark plug. Still popped.
Thanks for the explanation.