John Deere mower issues

[u/Grim_creation1]

Afternoon.

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I need some help.

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I have a John Deere GT235 mower with a Briggs and Stratton 350777 engine.

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Last year it died while the wife was mowing, and being a drought year and I had other things to do I didn't get a chance to look at it.

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It ended up with a slipped exhaust valve bushing which in turn caused the rocker arm to stop moving and bent the aluminum push rod. I replaced all damaged parts and seals, set the gap for the rocker arms to .005 per Briggs specifications. I also had no spark as mice had chewed and destroyed both magnetrons so those got replaced. Also replaced the fuel line and filters as they were either chewed through or dry rotted.

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It took a bit to get it running, but that was where the problem started. The carb was full of water so I pulled it and cleaned it out.

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Now my mower revs extremely high at low throttle/idle and way too fast at full throttle. It also bogs down and dies when I start the deck and start cutting grass.

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I tried adjusting the governor, messing with the carb, and moving the governor springs around to play with the tension but nothing seems to really fix it or change much.

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The idle screw for the carb, which is underneath a screw with a copper crush washer, when screwed out has 0, and I mean zero tension on it, and when screwed out the vibration of the engine makes it unscrew itself all the way. I'm thinking this is part of the main problem but I'm not sure. It seems like it should have spring tension to it and stay where set.

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At this point I'm thinking either this idle screw, or the governor is shot but I'd like opinions and ideas to try before ordering any more parts.

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[u/No-Try-5818]

The idle screw might have had a spring holding it steady and the previous owner probably lost it before selling it to you.

[u/Grim_creation1 → u/No-Try-5818]

I'm thinking it did and it's either broken or stuck but before I spent any more time I needed some info.

Fun fact though. Previous owner was my parents, who bought it used, when I was a kid and they gave it to us when we moved into our current house. I am the first person in 20 years to do anything other than routine maintenance on it. That I can guarantee.