ZTR Maintenance

[3Ts]

I have a John Deere Z525E 54" mower deck with the John Deere extended life engine which I think is the Briggs & Stratton engine. I have a problem with it surging at all speeds. It will mow and seems to have full power. I've replaced the air cleaner and fuel filter and it still does it. Next I'll replace the spark plugs, but we've moved recently and the owner's manual is packed in a box somewhere. Does anyone know what the proper spark plug & gap is for the machine? (No, I've not pulled a plug to see what's in there so I've not looked up a cross reference chart for the plugs.) If you have any other comments for things to look at about the surging, I'd appreciate them. The ZTR has about 50 hours on it and about 4 years old so not a lot of usage.

 

[RandyT]

Correct plug is most likely the RC12YC or BKR5E at .030 gap. And the surging is most likely a dirty carb issue. Most likely in the idle circuit of the carb. Not getting enough fuel through the idle gets so the engine rpm drops which causes the governor to open the throttle and pulls fuel from the high speed jet which increases the rpm and the governor reduced the throttle back to the clogged idle jet. Rinse and repeat.

 

[RalphVa]

I'd try some Seafoam. Just a splash into the fuel tank. Carb causes surging, not ignition.

 

[daman1]

Carburetor problem you need to get it cleaned

 

[LittleBittyBigJohn]

I agree, carb issue. You can probably find a new one on amazon for $30 to $40. I've replaced a bunch of them on various small engines and have always had good luck with cheep Chinese replacements.

 

[3Ts]

Thanks, I'll try the seafoam first, then if that doesn't work, i'll replace the carb.

 

[tomplum]

Just say no to aftermarket carbs! More will come back and bite you if they ever run good at all.

 

[LittleBittyBigJohn]

I have replaced no less than 7 factory ones on my own small engines with cheap chinese ones and have not had one issue. Saws, weed eaters, tiller, and mowers.

 

[rgr33]

I was expecting the worse when I first tried an aftermarket carb, but have never had any problem with them.
some are several years in service

 

[tomplum]

Yeah I on the other hand have those customers every year that pop new big A carbs on, and just can't get it running right. Sometimes they can bring the old carb and it gets fixed that way, others not and they get to buy an OEM on top of the mess they've created. That along with the ones that said it was replaced last year and the body inside is a corroded mess. YMMV