# John Deere GT235 Running rough at full throttle



## Emil Clintoc (May 26, 2018)

Hello,

I recently purchased a GT235 with the Briggs and Straton motor on it for my dad. It sat for a while, prior owner used it primarily to push snow as he had a zero turn mover, but tractor is/was in nice shape. Hood was not cracked, seat was nice. I bought it last fall and right after I bought it the engine started surging. So I took the carburetor off and took it in at a local shop to have it cleaned. I put it back on, but unfortunately I lost the choke linkage and when I went to turn it on while manually closing/opening the choke the engine would just turn off when dropping the choke. So I thought it was because I didn't have the linkage and could not quite hold it steady where it needed to be. I left the project to this spring. I put on the linkage recently and motor did the same thing as before. Started fine but as soon as I dropped the choke it would die. *It was not doing this prior to taking the carburetor to be cleaned. *It was just surging then. So I took the carburetor off again, drained it and opened it and it did have some dirt at the bottom of the bell. I spoke to JD service and they told me most likely one of my jets is plugged. So I opened both jets and made sure I cleaned them with a wire and also the small holes in the high speed jet. It looked actually in good shape with the exception of the low speed jet. That was a bit clogged. I sprayed the whole carburetor with cleaner, the needle looks good, needle seat looks good, the float was sitting properly and closing properly and put everything back together. I started up the motor and noticed it wanted to die first when dropping the choke but then moved it to lower speed and stayed on and runs steady. It runs nice and stays steady even at medium and 3/4 throttle, but as soon as I push it to full throttle it surges again, but now it does not die, it runs good for 15 sec then has a stutter or two and so on. Just does not run continuously at full throttle. A friend told me maybe the seat has a gasket that somehow fell off while cleaning it. It's a brass seat and did not notice a gasket inside, just the needle has the rubber tip and looks fine. I am considering taking it off again and leaving it in carburetor cleaner overnight and buy a complete kit for it. Carburetor seemed really fine to me with what I did the last time. My friend told me to check if the needle closes right, flip it over and try to pull air where the fuel line goes to see if needle closes properly. Said it should not leak any air (did not think of that). Any thoughts on this and what else I should look at? I really would hate to do the whole update and realize it is something else. Thanks in advance!!


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## Emil Clintoc (May 26, 2018)

I forgot to mention. I also bought a maintenance kit in fall with new fuel filter, spark plugs, oil filter and air filter and put those on with the exception of the oil and filter which I changed now. I did this with my brother in the fall and also filled up the tank then, thinking we will use it for the last mow, leaves, etc.


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## RC Wells (Dec 26, 2008)

I had a GT 200 series that did the same thing. The last time it turned out the fuel pump needed replacement. The other thing it did over the years was pinch the fuel hose from the tank to the fuel pump under the fender assembly, rerouted the hose and fixed that issue. Likely was pinched during the 100 hour hydrostatic transmission fluid change when the seat and fenders are removed. Then the fuel pickup in the tank was clogging another time, fixed it by taking the tank off and cleaning sediment out of the bottom. Tons of dust get sucked into the fuel vent in the cap in dry weather.


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## Emil Clintoc (May 26, 2018)

Thank u RC. Unfortunately it is not the fuel pump or line. I first took the fuel hose off to the carburetor to see if there is enough fuel coming to the carburetor. I gave it a crank and tractor started with the gas that was in the carburetor already and there was plenty coming out of the hose. I let it drain into a container. Then I used an old gravity fuel tank from another tractor and attached the fuel line to the carburetor holding the tank higher then the motor and it was still running exactly the same way, surging on full throttle. At this point I think I will just take it to the JD dealer service. I don't want to waste anymore time with it then I already did. I've already spent about two days on it with cleaning and doing the maintenance on the deck. I was thinking to take just the carburetor to them for them to clean it, but I don't want to go through all that again and realize it's something else. Not quite sure what it could be. Any other thoughts would be greatly appreciated, but I think that is what I will do at this point. I've already taken carburetor to be cleaned to a shop close by and another guy from the JD dealer service helped me make sure the jets are cleaned, so I think I will just take the tractor to them. I don't want to waste more time on it then I already did. Maybe they will do a complete update on it or tell me I need an new one. Or tell me it's something else. IDK..


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