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Chris Huber
Chris Huber, Small Engine Technician
Category: Small Engine
Satisfied Customers: 625
Experience:  20 years experience. Briggs and Stratton Master Service Technician. Dealer for most engine lines.
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Kohler 18hp 2 cyl opposed. The engine misses at gh idle and

Customer Question

Kohler 18hp 2 cyl opposed. The engine misses at high idle and will stop missing if I disengage the mower and lower the throttle to ½ position. The old plugs were black so I installed new ones but engine acted the same. There is no high speed needle on the carburetor. The problem went away when I changed the high idle RPM's to 2800 but should be 3400. I'm stumped and have been working on engines 58 years.
Submitted: 1 year ago.
Category: Small Engine
Customer: replied 1 year ago.
Air cooled.
Expert:  Chris Huber replied 1 year ago.

I would perform a cylinder balance test. Under no load, after warm up, carefully disconnect one spark plug wire at a time and note engine rpm change.

This will get you started on determining which cylinder the problem lies in. If the engine dies when one wire is disconnected, that cylinder is doing all the work. Let me know what you find.

Customer: replied 1 year ago.
It only misses with the mower engaged, I haven't taken the time to perform your recommended process.