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John Deere 240 losing power

7851 Views 5 Replies 5 Participants Last post by  Five Points
I have a John Deere 240. It runs good just driving around. The problem starts after the blades have been engaged and you have been mowing for 30 mins or longer. When it acts up it starts to "bog" down or lose power. If you move the throttle control to "slow" it seems to help it out and will begin to run ok, but only for a short time until it begins to do it again. Or I can disengage the blades and it will seem to start running smooth again. Seems to only occur when the engine is warm, blades engaged and mowing.

I have done or replaced the following:
Cleaned carb
checked fuel solenoid
replaced carb gaskets
replaced carb float (had gas inside it)
checked fuel lines
replaced spark plug
replaced fuel filter
replaced air filter
replaced fuel cap

This is actually my dads mower and I would really like to get it running for him..
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First of all, I would check the voltage in the battery prior to starting. Then, run it a bit until it starts to bog down and check the voltage then. Maybe you can hook up your voltmeter to watch the voltage as you are mowing and see what happens as it starts to lose power.
Welcome Winston!

Looking at John Deere parts it's a Kawasaki vertical crankshaft, single cylinder?

Couple other guesses would be:

(1) Maybe the engine is getting hot and the cooling fins need cleaned. (You've probably already checked that. ;))

(2) Bad ignition coil, weak spark once it gets hot. This one would also fit as with a load on the engine a weak spark issue seems to show up more as the governor allows the throttle to open putting more fuel in the cylinder per a given rpm.
I had a similar (not identical) problem on my GT245... it would start fine but stall out when hot as if out of gas, even with full tank. Only happened with blades engaged for some reason.

Replaced spark plugs with brand new, added blue Sta-bil to gas (local AutoZone guy suggested it... apparently these engines don't like ethanol-treated gas.) Total cost & time: $15, 15 minutes.
Update: Replaced the ignition coil and its like new again.. thanks for all the help.
Thanks for the update, glad you were able to resolve the issue.
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