PTO bogs motor down when engaged. I need help.

Ru4him said:
61" Ferris IS3000Z Water Cooled FD731V Kawasaki 25hp. This motor only starts on full choke and highest rpms. The PTO also only works when engaged with the highest rpms. This problem just started. When I engage the PTO the motor dies. If I quickly shut off the PTO and engage it again it works but the blades aren't spinning fast and the motor is chugging down. I took the belt off and tested the pulleys and spindles. All spin freely and no wobble. With the belt off, the PTO engages just fine and spins without wobble. Any ideas what could be going on?
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Bad Boy does the same....almost. Before fully warming up must use choke briefly. Full throttle to engage blades. I have a soft start on the blade clutch that really eases the clutch into full engagement. If you engage at less than full....yes it bogs down.
 
Auto Doc's said:
This favors a cylinder that is not producing power. These engines do not vibrate due to internal balancing and they are solid mounted.

My guess would be spark plug or coil. It may also be a dropped pushrod, and a valve is not working.
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It is the coil. Left cylinder isn't firing. New plugs. Swapped right plug with left and still no fire. I bought a new OEM coil and installed it, gapped with a business card. Still no fire. Both coils test good with a multimeter. I think I must have a dead short somewhere but can't find it.
 
slomo said:
How old are the fuel lines from tank to carb?
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They are old. It is the coil. Left cylinder isn't firing. New plugs. Swapped right plug with left and still no fire. I bought a new OEM coil and installed it, gapped with a business card. Still no fire. Both coils test good with a multimeter. I think I must have a dead short somewhere but can't find it.
 
RevB said:
Bad Boy does the same....almost. Before fully warming up must use choke briefly. Full throttle to engage blades. I have a soft start on the blade clutch that really eases the clutch into full engagement. If you engage at less than full....yes it bogs down.
Click to expand...
It is the coil. Left cylinder isn't firing. New plugs. Swapped right plug with left and still no fire. I bought a new OEM coil and installed it, gapped with a business card. Still no fire. Both coils test good with a multimeter. I think I must have a dead short somewhere but can't find it.
 
sgkent said:
the next thing would be to look for a vacuum leak. There are engines that have, for example plastic intake manifolds, that can crack. The symptoms you have listed are either lack of fuel or too much air. Bad fuel acts the same as lack of fuel. See if the engine runs better with the choke partially on. Also - a clogged main jet can cause that too, as can debris, a clogged fuel filter, etc.. I would also run a compression test on both cylinders because sometimes low compression can show up as mixture problems. At low compression the air molecules are farther apart.
Click to expand...
It is the coil. Left cylinder isn't firing. New plugs. Swapped right plug with left and still no fire. I bought a new OEM coil and installed it, gapped with a business card. Still no fire. Both coils test good with a multimeter. I think I must have a dead short somewhere but can't find it.
 
I am not sure of the ignition coil shutdown wiring on this particular engine, but you should be able to disconnect the harness lead at both coils and the coil in question will fire. If it does not, then you have a bad "new" coil possibly.

Also, some engine wiring harnesses have voltage flyback diodes in the ignition harness, and they do tend to go bad and that will mimic a bad coil.

This section of engine harness is often overlooked and misunderstood.
 
Ensure you have the correct coil for the replacement side.....there is a left and a separately numbered right. They are not interchangeable: The left and right coils are cylinder-specific. Swapping them can cause issues like no spark, weak spark, or misfiring on one or both cylinders. Service manuals explicitly note that the coils are different.
 
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