John Deere Gx75 Carb problems

11 years ago

So after 10+ years of being mothballed, I decided to try to use my dads old Gx75 rear engine rider. Got a new battery and the engine cranked. Took off the carb and cleaned it as best i could and success! It started and I could ride it again, but after maybe 15 minutes, It stalled out.

For about a week I would come home from work and ride it around for 10 minutes until it would stall and not restart. SO I decided to try and clean it some more. I tried to get the float and the float pin out and it broke, so I splurged on a whole new carb, figuring surely id put it on and boom, problem solved

Now with the new carb and new gaskets installed, nothing. Engine will turn over until the battery is dead, but it wont fire up. Replaced the fuel filter and spark plug figuring it couldnt hurt... But it sure didnt help.

Any Ideas?

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Comments (3)

rexlex
11 years ago
would start by fully recharging battery. Then, remove carb air breather. While cranking engine normally as to start, spray several shots of rattlecan carb cleaner directly into carb throat.
If engine "pops" or tries to start, you have a fuel delivery problem. If not, you have an ignition or mechanical engine problem.
fuel - remove fuel line at carb. using catch container and sparkplug wire removed, crank engine to verify good stream of fuel is being delivered to carb. If not, trace backwards and fix.
Be careful of stray sparks and gasoline fumes. If OK, carb needs full disassy/cleaning/rebuild with new kit.
Ign - remove plug, touch/hold threads to engine case. Crank engine, look for bright blue spark. chk plug gap and for fouling, etc. If no spark, look for ign sw prob, ign grd wire prob, or other ign items specific to your engine.
Mech - can be incorrect valve function, sheared flywheel key, etc. Best to get engine model/type info and then get service manual from engine mfgrs website for tech info or take machine to shop for repair. Good luck.
daft_punk
11 years ago
I think your original problem was with the fuel tank - specifically, the fuel cap. It's vented with a baffle and small hole. It's designed to let outside into the tank to replace fuel sucked out by the carb.

However, ten years is plenty long enough for insects to find a way into that hole. The gasoline fumes will kill 'em. It only takes a few decomposing bugs to clog the vent.

Under this condition, the mower will run for about ten minutes at a time. It'll stall when the vacuum within the tank is too strong for the fuel pump to fight. Had you simply unscrewed the fuel cap, it would have likely kept on running.

You likely still have this problem. Unfortunately, replacing the carb added something new. If the fuel line has an electric cutout, I'd check that. From there, I would follow the advice rexlex gave you.

Good luck !
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royex
11 years ago
I have a similar problem with my Simplicity 5212 with 12.5 hp B&S 404707 0122 01 87040812 engine code. I rebuilt the front part of the carb with gaskets and springs and also add a new fuel filter. Now the tractor starts nicely but after about 1/2 hour of running it loses power and stalls out. Starts again readily with the choke on. Happened about 6 times in the one hour i used it yesterday. I removed the fuel cap when it was losing power but it did not make a difference. Any thoughts on where to investigate.

Thanks