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

 

[stevem5215]

I've not had good luck with the chinese made carbs either. On an old B&S engine 7hp. And on several weekwackers and chainsaws no luck.

I'd try the "Mechanic in a bottle" from Lowes or Home Depot. They are nearby to everyone and they stock that stuff. Surging is due to dirt in the carb usually. New plugs won't hurt it but that's not your problem.

 

[bmg88201]

I had poor luck with those cheap carbs, I noticed a loss of power with them, put one on my Echo trimmer and it started and ran but at a loss of about 1/3 the power and rpm. Ended up buying an Echo carb and it runs like it did when I bought it new. Cheap carb was $25, Echo carb was $65, so now I’m out $90.

 

[BoylermanCT]

I've had no problems with the cheap Chinese carbs. Worked perfectly in my weed whacker and push mower. That said, I am slowly converting all my gas lawn tools to cordless. The batteries are getting better and better and the power on the newer tools is equal to gas.

I second Seafoam. I had another push mower that surged and Seafoam solved the problem.

 

[3Ts]

This is to follow up on the post and let y'all know what the fix was.

I got a bottle of seafoam, put it in the tank and started up the ZTR. It surged which I expected it to do, then went out and mowed the yard. 2 hours later I came back to put it away and it was purring just like new. The seafoam worked just like y'all said it would. I've not done anything with the plugs, I'll wait until they come up in the maintenance schedule.