miss while with no load

[drifter420]

I have a dinosaur of a riding mower but it has been pretty reliable.
It's a white LGT-1155 with B&S 11HP motor.

When it's just idling with no load ( blades not engaged ) I get a random miss, but when underload, it runs fine.

I read in one of the other thread regarding possible lean condition causing after fire in the muffler ( when shutting down the motor ).. and was wondering if they would be related.

I"m not familiar with the carb, but which needle setting is for idle and hi so I can try richening it.

The plugs has been changed 2 years ago, and recently went thru sea foam thru carb and gas. It helped some.. but still there.

Any suggestions?

 

[Bill Kapaun]

"I"m not familiar with the carb, but which needle setting is for idle and hi so I can try richening it. "

With out the engine model, type & code, how can we be familiar with your carb either?

My gut feeling is it's something you're going to have to live with. It could be a plug misfiring, a valve sticking or just kind of the nature of the beast. A lot of engines miss ocassionaly at high speed -no load.
As long as it runs good under load, that's the main thing.

 

[drifter420]

Thats true bout the working fine under load who cares motto. But if I can make it better.. why not?

I wasn't able to find any model # on the engine or code

The sticker just says 4 cycle 11HP @ 3600 RPM
synchrobalance 399cc

 

[Bill Kapaun]

http://www.outdoordistributors.com/Briggs_And_Stratton/briggsmodelid.html

 

[drifter420]

I checked the motor several times to ensure I missed it.. but to no avail.

Based on the picture that BK has kindly linked. IT is the motor at the bottom left

 

[Bill Kapaun]

499CC would "probably" place it in the 25x7xx series, assuming it's a vertical shaft engine.
Trouble is, there are something like 9 different models in that series.

IF you have 2 separate needles, you could try either one and see what happens.
Try backing out 1/2 turn (richens) or so.

 

[yeehaw1960]

I thought small engines always burped a little when not under load. Something to do with the harmonic balance depending on the load to keep things straight.