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.
B&S twin 20hp, one cylinder runs hotter
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Cam timing comes to mind. Maybe a bad camshaft? If the carb and all is 100%, only thing left is opening her up for a CSI investigation.
Possibly set valves on wrong stroke?
Honestly I wouldn't lose sleep over it. On a typical v-8 for example, every cylinder will not have the same air fuel ratio and temp as well. Many a factor causing this. Cylinder head torque and sealing condition. Valves and so on. Could be down to one coil firing hotter or a weak coil for example.
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I hear ya' but just stating the obvious, there are 2 TDC strokes on a 4 smoke engine. Many a folk try it on the wrong stroke and we go to about 15 pages on here LOL.
bertsmobile1
Lawn Royalty
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Depending upon which carb is fitted, some have jets of different sizes in the 2 barrel nikki carb
Easy to swap them over which causes one side to run properly & the other to run lean
Another EPA solution to a problem that does not exist
I usually toss the small one and go back to the original large jets
Easy to swap them over which causes one side to run properly & the other to run lean
Another EPA solution to a problem that does not exist
I usually toss the small one and go back to the original large jets
- Joined
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Left jet is 1.13mm
Right jet is 1.16mm
O-rings on the jets are bad to shrink allowing the jets to float around causing over rich fuel mixtures.
And yes trash from changing the fuel filter can cause problems too.
Right jet is 1.16mm
O-rings on the jets are bad to shrink allowing the jets to float around causing over rich fuel mixtures.
And yes trash from changing the fuel filter can cause problems too.