Z925A - Won't Re-Start When Hot

[tjrigario]

I've got a roughly 11yr old Deere Z925A Zero Turn with a Kawasaki FX751V on it. The motor runs good and strong, but never wants to restart after it's up to operating temperature. I've changed the coils and rebuilt the carb. Neither of those have corrected the problem. There's a fuel shutoff solenoid on the back of the carb that's been checked as well, and it's functioning as designed. I'm officially out of ideas! Has anyone experienced this before?

 

[Tiger Small Engine]

I've got a roughly 11yr old Deere Z925A Zero Turn with a Kawasaki FX751V on it. The motor runs good and strong, but never wants to restart after it's up to operating temperature. I've changed the coils and rebuilt the carb. Neither of those have corrected the problem. There's a fuel shutoff solenoid on the back of the carb that's been checked as well, and it's functioning as designed. I'm officially out of ideas! Has anyone experienced this before?

The emergency brake on these mowers can get out of adjustment, and not allow mower to start. Had this happen to a customer mower I was working on, and couldn’t figure it out. John Deere dealer resolved the issue. John Deere is very secretive and protective of their technical information and are often different than many other mowers is frustrating and difficult ways.

 

[StarTech]

Sounds like the ECU is giving problems when hot. Personally you need to determine which system is failing and do a bypass surgery on the ECU wiring. I had fuel solenoid circuit failures, magneto kill circuit failures, and PTO circuit failures on these ECUs and just did bypass surgery on them to return the ZTRs back full operation with all safeties intact.

But the OP will need the wiring schematic and the knowledge of how to do these bypasses.

 

[tjrigario]

Sounds like the ECU is giving problems when hot. Personally you need to determine which system is failing and do a bypass surgery on the ECU wiring. I had fuel solenoid circuit failures, magneto kill circuit failures, and PTO circuit failures on these ECUs and just did bypass surgery on them to return the ZTRs back full operation with all safeties intact.

But the OP will need the wiring schematic and the knowledge of how to do these bypasses.

Interesting. Do the carbureted models have an ECU? I can get it started with a lot of effort, but it backfires like crazy and isn’t happy.

 

[tjrigario]

The emergency brake on these mowers can get out of adjustment, and not allow mower to start. Had this happen to a customer mower I was working on, and couldn’t figure it out. John Deere dealer resolved the issue. John Deere is very secretive and protective of their technical information and are often different than many other mowers is frustrating and difficult ways.

I’m skeptical it’s the parking brake as there is still spark, etc. when cranking. I did manage to get my hands on the Kawasaki service manual. The motor has good compression, but I’m going to try a leak down test to make sure everything is good. I’ve heard these motors get pinholes in the head gaskets and leaks can be hard to detect.

 

[StarTech]

Interesting. Do the carbureted models have an ECU? I can get it started with a lot of effort, but it backfires like crazy and isn’t happy.

Yes but it is not the same as EFI control module.

 

[smalltimerpm]

Interesting. Do the carbureted models have an ECU? I can get it started with a lot of effort, but it backfires like crazy and isn’t happy.

Does this effort mean starting fluid? Is it backfiring thru muffler or carb? If your firing Is correct It does sound like a intake on fuel issue. The fuel plungers are known to get hot and quit working at times and coils are also. Maybe check intake gaskets along with the above I mentioned. Also check fuel passage all the way from tank to carb.

 

[tjrigario]

Does this effort mean starting fluid? Is it backfiring thru muffler or carb? If your firing Is correct It does sound like an intake on fuel issue. The fuel plungers are known to get hot and quit working at times and coils are also. Maybe check intake gaskets along with the above I mentioned. Also check fuel passage all the way from tank to carb.

I don’t typically have to use starting fluid. Just keep cranking and cranking until it goes. Backfiring is coming from the muffler

 

[Bertrrr]

I'd change spark plugs first - easy to do and might correct your problem - possibly the plug is failing when hot. If it eventually starts that pretty much eliminates the solenoid on the carb.

 

[bertsmobile1]

Every time the engine revolves it dumps fuel into the muffler if the fuel is not burned in the engine
When the air: fuel ratio is correct for burning at atmospheric pressuree the unburned fuel in the muffler ignites so it goes bang.
This indicates that either you have bad plugs or the timing is way too far retarded