Engine started running rough, wouldn't recover from load on tall grass without jerking the machine or disengaging the blades. Changed the fuel filter. The coil was weak, so I changed that and plugs, great spark, still won't run on cylinder 2 alone. Slight misfires when throttling up and down quickly. Adjusted the valves, still won't run. Brought it in because I don't go much further than that, figuring it is a compression problem, gasket or worse.
Service department calls and says it is in the fuel system. I asked if they checked compression and why would one cylinder runs seemingly fine, but the other doesn't if it was the carb. Just wondering what y'all might think.
possibly, your engine repair manual is 18 down, section 10 page 2, two coils/ modules are on your engine, did you replace both & set air gap to specs.?
possibly, your engine repair manual is 18 down, section 10 page 2, two coils/ modules are on your engine, did you replace both & set air gap to specs.?
These engines make spark by cranking them over. An electrical harness is connected to each coil for the purpose of being able to shut off the engine.
Twin cylinder small engines that have two separate ignition coils have a "Y" electrical harness connected to each coil. The two legs of this harness connect the coils to a single wire that goes to the key switch which, when in the off position grounds both coils to shut off the engine. To prevent cross feeding of the coils, there is a diode installed in each leg of the Y harness. Different situations happen depending on which diode has an "open" or a "short".
The best way to check for spark is to disconnect these wires from the coils and perform a spark check at each cylinder. The Y harness can be isolated by disconnecting the engine harness, identifying the Y harness single terminal and performing a continuity check on each leg of the Y harness at the disconnected coil terminal end. To correctly check a diode, the meter test leads (red/black) must be reversed as a diode is an electrical check valve so to speak.
