# 58 420 with a carb problem



## Groo (Jan 17, 2020)

It has one of those old updraft carbs. looks like cast iron.
Fires right up, runs for awhile, then goes rich and dies.
I can shut off the fuel at that point and crank it until it fires again, and it goes rich again eventually after opening the fuel again.

I did a halfassed carb cleaning by taking the bowl off and spraying everything with carb cleaner. It went quite a bit longer before going rich, but it eventually happened again.

I see 3 options
1) pick up a carb kit and rebuild it myself
2) buy a new or rebuilt carb... leaning towards new if I go this route. 
3) convert to efi

that would also be the order of increasing cost as well.

If I rebuild it myself, which area should I be looking at for this problem?
Could it just be the float has a hole in it? 
thinking about it, this is making the most sense I always turn the fuel off when parked, and it will just sit there an idle "forever". its just when I drive it that it goes rich.


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## Groo (Jan 17, 2020)

purchased a Zenith replacement For about $150.

should be in tomorrow, and hopefully installed this weekend. looks like it will above 30 Saurday afternoon.


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## deerhide (Oct 20, 2016)

Could be a hole in the float but I would go the new one.


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## Groo (Jan 17, 2020)

this looks like its going to be a pain.
All the levers are on the wrong side, and there is absolutely no documentation.


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## FredM (Nov 18, 2015)

You could have repaired the float if this had a hole in it, most of the older floats were brass and this could have been repaired with a little solder if there was a pin hole in it, I don't suppose you would have pulled the float needle to see how the needle point was or if there was some dirt or such that was not allowing the needle to seat, maybe you should have given the carby a full service and clean and saved your money on a new one that may not be suitable.

Does your carby have a power mixture screw ?, did you try adjusting this to lean out the carby ?.


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## Groo (Jan 17, 2020)

I popped the bowl off, and sprayed the crap out of it, including the needle and seat, with carb cleaner. When the bowl was off, I noticed the floats were partially crushed. That might have happened because of a backfire (I did run it dry before the problem started). My reading suggests most people blaming it on water in the gas. i highly doubt that. It ran maybe an hour before running dry, without a problem. The crushed and/or perforated float might have been the whole problem, but then again it might not have been the whole problem, and what would happen with the next back-fire? Seems like something else must be going on to allow that to happen.

The machine runs fine, until it starts to die, then I've got another 5-10' of travel remaining. Once it dies, I can shut off the gas and crank it for awhile until it runs again...then open the fuel valve again, and go for a bit (further than if I leave it closed) until it floods again.


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## FredM (Nov 18, 2015)

what happens if you don't turn the fuel cock off after you park up ??.


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## Groo (Jan 17, 2020)

I havent left it open since this started.

it doesn't start spilling out.


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## FredM (Nov 18, 2015)

So the carby is not flooding then, shows the needle and seat plus the float is working, , I did ask previously if you had tried to adjust the power mixture needle to lean out the fuel??.

Another thought is "you have said the float is crushed from a backfire", I suppose this could be possible, but I have never heard of it, have you thought of checking the crushed float level since the backfire, the fuel level may be higher in the bowl due to the floats being crushed and this will give you a flooding mixture.

I really think you need to remove this carby and pull it down and check out the internals, give it an eyeball to see if you can pick up any faults.


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## Groo (Jan 17, 2020)

I researched the crushed floats, and got 3 possibilities put forward.
1) water in the gas freezing it and crushing it. BS. any water in the bowl would be below it. it it was filled 100% with water, maybe, but not the case for the few years I've owned it, and the tank looks original. If a carb filled with water, the tank would be garbage, and most likely the machine would not have been worth fixing at all.
2) cleaning with compressed air. maybe the previous owner did, but I have my doubts. he was basically rebuilding Deeres as a retirement hobby, and he knew what he was doing. He had been messing with them since before mine was new.
3) backfire. This problem started after running it dry, so I strongly suspect that is what caused the problem somehow. I've got my doubts on crud making it through the fuel filter and the way that moving the tractor plays a role in the problem starting up, suggest to me it might be a float sinking.

I was sort of assuming that the needle closes when things are still. If the carb, intake manifold and air filter hose were full of fuel, I would think it would hydro-lock, and likely leave a huge puddle as well.


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## FredM (Nov 18, 2015)

it is an updraft carby so won't hydrolock, there should be a fuel overflow drain built into the air horn, the part that the rubber hose from the air cleaner connects to and this allows fuel to escape should the carby flood.

While the engine is running, the float and needle are working continuously.


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## Groo (Jan 17, 2020)

right, but something is happening when the machine is moving that causes it to go so rich it wont run. I have my suspicions on what it might be, but I couldn't be sure. that is why I spent 3x what a cheap rebuild kit would run on a new carb. Now i get to try to figure out what threads an Indian copy of an ancient US carb would use.


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## Groo (Jan 17, 2020)

This replacement carb is being a royal pain. It's like it could be configured numerous ways, but they always picked a different way than deere did.everything is on the wrong side and usually the wrong oritation. The "universal" throttle lever doesn't adjust short enough and the nut holding it in place is going to interfere. At least they tapped all 3 fuel inlet options.

Now off to tap the stud holes so I can use the bolts that the tractor uses


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## Groo (Jan 17, 2020)

After installation, what I feared became apparent and the throttle was not able to fully close with the nut interfering with the governor lever, so I made some adjustments. Seeing how it runs now, I can see it wasn't working properly before. 

I still haven't hooked up the choke, and it certainly looks like I don't need it. It is either because of it still running way rich or the new ignition just works that well, maybe a bit of both.


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