jd 345 engine surge

[dave in need]

got a jd 345 that surges and have cleaned carburetor 3 times
even soaked it good in carb dunk tank and it still surges
no noticed vaccuum leaks found and float level is good
a real stumper any help would be appricated thx dave

 

[Dude11]

Hi Dave,What engine and carb.are we talking about?Dude11

 

[Anonymous-0]

get a new carb from Deere and put it on. I would have replaced it when it kept surging after cleaning it the first time.

 

[jd b puller]

Dave, 345 or GX345? Does it do it all the time or just once it's warm?
What kind of temps do you have?

Make sure the carb vent line is clear and not full of spider webs. Normally that'll make em run rich though.

If it surges when warm, spray some water on the carb bowl, they like to vapor lock.

Make sure the gas is new from a high volume station. Winter blend fuel has higher concentrations of "light ends" in it and make it more prone to VL.

Make sure your radiator fins are good and clear as well. Higher under hood temps will contribute to the VL.

And it could be that you either aren't getting the carb clean, or it's time for a new one $$$$ - I was thinking they were about $300 though. Check out the easy things first!

 

[dave in need]

its a 345 with a FD611 engine
It surges all the time
Thanks for all the replys
Dave

 

[Dude11]

Dave,I guess i should have asked,what make engine and hp?

 

[mowr]

A common cause of this problem with many carbs is that a steel throttle shaft rotates in a soft housing (pot metal, etc.). After a while, the soft metal wears enough that air comes in past the throttle shaft, leaning out the mixture. The engine begins surging as it tries to compensate for the problem and as the cycle increases, the rate of wear escalates. The 345 I mow with is heading in that direction (surges at low to medium speeds and light loads) but still works smoothly when mowing. Some people solve this problem by boring carburetors and installing bushings to restore the proper fit and have a job that wears better than the original. Whether that can be done with this carb, I don't know, but it might be worth checking into.

 

[Anonymous-0]

I had that problem with mine from the day I bought it(2001). Took it back to the dealership MANY times--"Nothing wrong with it". Last week I went to start it, it would crank but not fire. Ended up replacing the spark control box. Now it runs perfectly, no surging, smooth through all rpms.

 

[Mark Alloy]

I am having the same problem with surging on two JD mowers .One is a 125 with Briggs & Stratton engine and the
other is a JD 345 lawn tractor with 24 HP Kiawasaki . Both tractors have new chinese carbs The JD 345 has all new fuel
system.

 

[Roger in Iowa]

Does chocking help remove the surging? If so, you have carb problems. Plugging, throttle shaft worn, air leak, or main jet too lean, ????

 

[Mark Alloy]

got a jd 345 that surges and have cleaned carburetor 3 times
even soaked it good in carb dunk tank and it still surges
no noticed vaccuum leaks found and float level is good
a real stumper any help would be appricated thx dave

I have new carb,new gaskets and all new fuel system including fuel pump.
A slight bit of choke seems to help the surging.
I replaced original carb because of old fuel/ gummed up carb,and yes I should have rebuilt JD carb.Before old JD carb was messed up with old gas,it never surged and had little over 700 hours on it.
Because old JD carb never surged,I feel like problem is with aftermarket carb.I also have aftermarket carb on JD 125 which is a Briggs &Stratton engine.It will very seldom Idle and when it does it surges as well .At full throttle it runs fine