brand new B&S surging after 1.5 hrs use

[slomo]

if the needle were stuck open does that cause fuel to run out faster? The second tank seemed to go pretty quickly.

I would say yes.

 

[animattor]

Well I got it back from service. Mechanic told me it was the carb, generically. Mowed the lawn one time, and it ran better but not great. Then I changed the oil after the first 5 hrs usage. And then it wouldn't start at all. It's back at service again.

 

[Tiger Small Engine]

Well I got it back from service. Mechanic told me it was the carb, generically. Mowed the lawn one time, and it ran better but not great. Then I changed the oil after the first 5 hrs usage. And then it wouldn't start at all. It's back at service again.

Please follow up once you get answer to issue.

 

[animattor]

the saga continues. I pulled out mower for the first time this season, and it started right up. cut well, ran smooth for about an hour and then started surging again. Fuel bowl is clean, the float moves freely, and i tried cleaning idle jet with canned air (i don't have anything small enough to try physically unplugging the jet). there is no debris in air intake. I put in 75% fresh fuel (mixed with a little left over from last season).

At the end of last season mower was at service and running well.
Here's a video of the surging at idle.
any suggestions appreciated. I'd like to get to the bottom of this. It is still under warranty, but for service, not return. In about 10-12 hours of use it was at service three times last season.

 

[Tiger Small Engine]

the saga continues. I pulled out mower for the first time this season, and it started right up. cut well, ran smooth for about an hour and then started surging again. Fuel bowl is clean, the float moves freely, and i tried cleaning idle jet with canned air (i don't have anything small enough to try physically unplugging the jet). there is no debris in air intake. I put in 75% fresh fuel (mixed with a little left over from last season).

At the end of last season mower was at service and running well.
Here's a video of the surging at idle.
any suggestions appreciated. I'd like to get to the bottom of this. It is still under warranty, but for service, not return. In about 10-12 hours of use it was at service three times last season.

Is it surging at wide open throttle under load (while cutting grass)? If not, then run it, or find another shop that can fix it. You can also shorten the spring to throttle that helps control the butterfly, therefore minimizing the surging.

 

[animattor]

Is it surging at wide open throttle under load (while cutting grass)? If not, then run it, or find another shop that can fix it. You can also shorten the spring to throttle that helps control the butterfly, therefore minimizing the surging.

It started surging while cutting tall grass but still surges at idle. (The video was taken at idle)

 

[GearHead36]

It started surging while cutting tall grass but still surges at idle. (The video was taken at idle)

Surging while cutting tall grass? Are you sure that this wasn't just the result of a heavy load on the engine. Patches of tall grass will put a load on the engine, and will cause it to slow down. If you have patches of tall grass, it could seem like a surging engine.

A general recommendation... ALWAYS run your OPE at full throttle. Mowers, trimmers, edgers, chainsaws, etc. All of it. It's ok to run at low throttle for short periods, but the cheap carbs on these engines are tuned for optimum running at full throttle. They will run ok at part throttle, but will cause lots of carbon deposits. With mowers, you should also use full throttle to get the proper airflow through the deck. My push mower is a Toro Recycler with a Briggs flathead engine. It doesn't even have a throttle control. It's always at full throttle. Part of me thinks that running a cold engine at full throttle is hard on it, but it's 13 yrs old, and has never needed a service, other than a governor spring that got destroyed. The carb has never been off the engine, and has never been opened up.

 

[slomo]

the saga continues. I pulled out mower for the first time this season, and it started right up. cut well, ran smooth for about an hour and then started surging again. Fuel bowl is clean, the float moves freely, and i tried cleaning idle jet with canned air (i don't have anything small enough to try physically unplugging the jet). Fishing line. there is no debris in air intake. I put in 75% fresh fuel (mixed with a little left over from last season). Try dumping, blowing out with shop air, finally confirming the fuel tank is free of debris.

At the end of last season mower was at service and running well.
Here's a video of the surging at idle.
any suggestions appreciated. I'd like to get to the bottom of this. It is still under warranty, but for service, not return. In about 10-12 hours of use it was at service three times last season. Surging is a dirty carb or vacuum leak mostly. Something in the fuel delivery.

 

[animattor]

I took it back to the mechanic today. He thinks the problem is due to the partially old fuel I used—gummed up something in the carb. Guess I should have just dumped the .5L leftover and saved myself some trouble!

 

[slomo]

I took it back to the mechanic today. He thinks the problem is due to the partially old fuel I used—gummed up something in the carb. Guess I should have just dumped the .5L leftover and saved myself some trouble!

Could be.

I always use fuel stabilizer. Why? I forget how old my fuel is. Don't have to worry about old fuel anymore. My fuel doesn't get gummed up.