B&S twin 20hp, one cylinder runs hotter

[slow030]

Took the carb bowl off and cleaned, sprayed the jets. Still pops. Should I take carb completely apart and clean, replace jets?

 

[bertsmobile1]

Yes
Gt the rebuild rubber kit and replace both of the O rings around the main jets
Do main jets 1 at a time to avoid mixing them up .
They do have their sizes marked on the sides but you will need a maroscope to read them
I regularly come across them that are reversed .
Outdoorpowerinfo.com will have a detailed photo description of how to do it properly .

 

[daman]

Take the engine shroud covers off is there clippings and debris plugging the cooling fins on the cylinders?

 

[slow030]

Just ordered o ring kit. Thanks

 

[slow030]

Installed the O-ring kit and it runs great. No more popping or sputtering. Thanks for the help.

 

[bertsmobile1]

Excellent result.
Thanks for coming back
Happy mowing

 

[slomo]

Take the engine shroud covers off is there clippings and debris plugging the cooling fins on the cylinders?

Of course. But that isn't talked about much. I get oh yes my fins are clean. 8 pages later the OP puts a picture up of the block. Sure enough, fins are slimed over. OP, carb was cleaned too. Picture picture, carb was heavily loaded down with oil and grit on the outside.

 

[flyhalhl@gmail.co.]

Trying to help my neighbor. John Deere L120A B&S 20hp twin,406777 0139 E1. Has some popping and loss of power. Checked with infra red thermometer and the right side exhaust is about 100 degrees cooler than the left. 1. swapped plugs, no change. 2. checked compression, both around 140. 3. Checked valve lash on both, all set correctly. 4. Checked valve travel, both exhausts were same and both intakes were the same. 5. Will run on each cylinder by itself. 6. Checked diodes in coil ground, both good. 7. Checked flywheel key, good. 8. Checked for intake leak by spraying carb cleaner around all mating surfaces, with no change in running. Not sure what to do next, any help appreciated.

Any dirt buildup around cylinder?

 

[flyhalhl@gmail.co.]

Took the carb bowl off and cleaned, sprayed the jets. Still pops. Should I take carb completely apart and clean, replace jets?

 

[flyhalhl@gmail.co.]

Most if these carbs have single throat carbs, thus common jet for both cylinders. May be intake leak on gaskets causing that cyl to run lean.