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Discussion Starter #1
I just bought a Magnum 400 and the carburetor will need to be cleaned out from where it has sat for several years. I've cleaned/rebuilt dozens of carburetors on just about everything. I found it to be hit or miss.

The last carburetor I messed with was on my daughter's "Peace" 110cc ATV. I took it apart and it had a bunch of green funk in the fuel bowl and jets.

Afterwards it ran but fouled the spark plug where it was running too rich for some reason. So I ended up just buying a new carburetor for $13. For that price, they are not worth messing with.

If I have no luck cleaning this Mukini carb on this Magnum 400, have any of you guys found a Chinese knockoff that will work on this engine without having to muck about with jetting and all?

No I don't have the model number of the carb but while I have it off, I'm going to write it down in case I have no luck cleaning it out.

Also, what have you guys used? I've used everything from soaking the carb in fuel injection cleaner, boiling them on a hot plate with Purple Magic.

I've heard MEK (which is technically a paint thinner) works well. I smuggled some out of work and plan on giving it a shot.
 

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In my experience its very rare for a carburetor to ever be unrepairable. If its bad enough on the inside a kit from ebay or wherever with new o rings and replace any jets you can't get unplugged will do the trick. I seldom use the whole kit. I only use the parts needed for that particular carb and save the rest for future projects. I've built up a pretty good collection of carb parts over the years and often don't even need to order anything to refurbish a carb.
I just use carb cleaner and compressed air to clean. Set everything to factory spec and adjust from there if needed. Float valve seats can be polished with a qtip chucked in a drill with a little polishing compound on it.
 

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Discussion Starter #3
In my experience its very rare for a carburetor to ever be unrepairable. If its bad enough on the inside a kit from ebay or wherever with new o rings and replace any jets you can't get unplugged will do the trick. I seldom use the whole kit. I only use the parts needed for that particular carb and save the rest for future projects. I've built up a pretty good collection of carb parts over the years and often don't even need to order anything to refurbish a carb.
I just use carb cleaner and compressed air to clean. Set everything to factory spec and adjust from there if needed. Float valve seats can be polished with a qtip chucked in a drill with a little polishing compound on it.
The thing about the carb on this Chinese ATV was the jets were so clogged up I had to burn the funk out with a propane torch. This black goo oozed out. I'm starting to wonder if the jets on these things were filled with some epoxy then drilled out to match the engine size.

I tried using a needle, compressed air, soaking in carb cleaner to no avail.

And when I used a propane torch, I enlarged the holes and that's why the bike ran rich. It smoked a bit, ran OK but when stone cold wouldn't start due to the fouled spark plug. I don't think it was the float level because gas never leaked fuel into the crankcase or onto the ground when sitting.

Well should go to the ground. On newer lawnmowers, the fuel bowel seems to vents through the intake. That's why when the float sticks, it fills the crankcase full of gas. Must be some emission thing.

I've had issues with B&S carburetors that were not repairable for some reason. Or I've never had any luck fixing them. Seems the throttle shaft will wear out over time due to constant opening and closing when use on go-karts and mini-bikes. So they won't idle due to air being sucked in around the throttle shaft.

I was really surprised I managed to fix my friend's Bruin 350. The carburetor on that thing is more complex than an old Weber on a car. I did not have a good feeling about it but when I put it back together and slapped it on, the bike ran and idled just fine.

The jets and fuel bowel on that thing was clogged up with the same green funk on this kid's ATV he gave me. It looked like algae. I've never seen this stuff in a carburetor before. Any residue is usually white or brown.

But managed to clean it out without using a propane torch.
 

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Discussion Starter #5
What year model is it?
I think he told me it was a 1996 model. My 1997 model has a VIN and the service manual explains what it means. I don't know if this model has a VIN or not. When did they start putting VINs on ATVs? Is there any other way to identify what year it is?

Here is a good price on a carburetor and it looks identical to the one on mine based on the fuel inlet port and the two nipples coming off the sides at an angle (whatever those are for).

Polaris 425 Magnum Carburetor/Carb 1995 1996 1997 1998 NEW | eBay

QUESTION: What's the difference between a Magnum 400 and a 425? This carburetor is supposed to fit a Magnum 425. Would it work on a 400?
 

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I just bought a carb for my 99 335 sportsman from zoom zoom parts on amazon it has a hesitation until it gets good and warmed up. but I haven't adjusted it or anything. shipping was lightning quick too. I think it cost around 50 bucks.
 
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