B&S 140cc Lawn Mower

I have the following B&S engine on my Troy Bilt Mower. Serial # RE00 0003 23878
Engine model 9P702 0005 F1 Serial # 1C052K91254

I have had to have my mower into the service department twice now in 13 months (as you know I only cut 1/3 acre twice a week for 8 months out of the year)

This problem reoccurs -- when it cranks cold it surges up and down for about 2 minutes then smooths out -No Problem I do not think. The problem is I will pull it to crank it cranks and in 5 seconds dies out. It continues this pattern. Then it will crank then cut for 15 minutes and die on it own. Then sometimes go away it will then start up and crank. The outside tempp is around 65-70F. They blamed it on old gas but the gas was fresh and stabilized. What can this be???

 

It sounds to me like it is running too lean. That would be a carb issue.

 

Did they even bother to pull and rebuild the carburator?
I use nothing but nonethenal fuel, add Sta-Bil to the fuel and still almost every year have to pull the carburators off and clean it out.
This year I had to replace the fuel pump, it was full of rust and the diaphram was broke.

 

Cheese do these model carbs typically have more problems than the older B&S Sprint model carbs? What can I do to keep these model B&S carb clean and free of the ethanol build up issues? I use the Lucas Ethanol Stabilizer that is sold by Lucas Oil. What about using a 1 ounce amount of Sea Foam to the gas tank at the end of the mower season when I am running it dry for storage? Is Sea Foam bad for mowers??

 

I like seafoam, it is one of the few fixes in a bottle that I actually believe in. I think it's pretty much just acetone, judging by the smell of it. I don't know if these carbs are more trouble than the others or not, they haven't been out long enough to form a track record.