Kohler Mag 20 dumping fuel again

[HKCooper44]

I have a Chinese carb, new, sitting in a box, and now I'm hesitant to even install it. I see now that the choke shaft, butterfly and actuator arm are exactly backwards from the Walbro, and wonder it the Walbro choke shaft can be installed in this new carb.

It seems odd that since operating an Original as a young teen, a 105 as a young adult, and a 100 since 1985 up to now, all of them having gravity fuel feed syatems, that I NEVER had a cylinder flooding problem until getting this 782 last year!

 

[MarcHeld]

I have a Chinese carb, new, sitting in a box, and now I'm hesitant to even install it. I see now that the choke shaft, butterfly and actuator arm are exactly backwards from the Walbro, and wonder it the Walbro choke shaft can be installed in this new carb.

It seems odd that since operating an Original as a young teen, a 105 as a young adult, and a 100 since 1985 up to now, all of them having gravity fuel feed syatems, that I NEVER had a cylinder flooding problem until getting this 782 last year!

www.ISaveTractors.com has your back on that. They provide a reversed choke lever in the box, with instructions on how to swap it.

 

[mgonitzke]

Option 3, get a good used Kohler #26 carb from a K241 or K301, and switch over the choke and throttle shafts. The isavetractors carb is also a Chinese carb, with a higher markup and presumably better quality control. Most people have had good luck with those, but I've heard a few less positive reviews as well. You can't go wrong with a good used carb.

You likely never had this issue before because when the float gets stuck or needle and seat fails on a K-series, the gas just runs out the bowl vent and out the air filter. On the opposed twins, the only place for it to go is into the intake manifold and into the cylinders.

 

[HKCooper44]

True.

 

[tkhoffman]

You may want to check oil level. Gas can get passed the Rings and into the sump.
Smell the dipstick for gas odor

 

[HKCooper44]

Did it. Oil level didn't rise, and didn't smell like gas. With this new shutoff valve i put in, hopefully the issue is solved. I have a spare carb here, just in case.

 

[Stu]

I got a full motor rebuild kit from issavetractors for my 1250 which included a carb. Carb worked fine but the throttle butterfly was a bit stiff, so did not respond to the governor quite right. I cobbled together a very weak “spring” to help it return, been running fine for 3 years.

 

[jack casey]

I think we’ve all been there. Besides the bad needle design in the Walbro carbs, the design of the 82 series with the fuel tank positioned higher than the carburetor contributed to the issue. When the tank was less than half full, you were typically “safe”. If you filled fuel to the top, and let it sit unchecked, the fuel would syphon down through the carb into the intake manifold and down into the cylinder. Shutoff valve is a good fix, but there will be a moment when you fill the tank and forget to shut the valve.

MTD improved the situation on the Cyclops series by swapping the location of the fuel tank with the battery. This way, the tank is lower than the intake and is impossible for a syphon to set up. Downside of this is they over complicated the fuel lines. Upside is, they can fit a bigger battery.

I have since replaced the Walbro with a Kohler clone from www.ISaveTractors.com. Have had zero problems since. Important to note these are not Chinese junk, the cheap ones on Amazon are. Don’t waste your time with those.

Really dangerous!
This gas dumping is more common than I thought - it happened to me. I have a CC102 with the oem carb. Did not think the needles were bad, could not adjust them, removed the air cleaner and fiddled some more. Good thing I can't reach the start key while being close to the carb, you wouldn't believe the amount of raw gas that blew out. So, if you cannot make adjustments, STOP AND GET A NEW CARB from ISave or another US mfgr.
Cheers, Jack

 

[HKCooper44]

The KT-17 engine, in itself, isn't a bad design in my view, but the location of the fuel tank in the Cadet 782 makes it so because a failed or failing carb needle/seat allows gas dumping when the fuel tank is over half full! This, plus there is no readily accessible fuel shut off valve one can access by raising the hood.

 

[rfunk]

Around here most of the loggers have switched to aviation fuel for their chainsaws. Even “ethanol free” has traces of ethanol. Not long after ethanol came out I went through three fuel lines in one saw in just one season. Stihl adapted and came out with new fuel lines of a different composition but still problematic. Av fuel solves all those problems, just spendy. But it makes for a smooth, clean, hot running saw.

Aviation gas contains lead, and more than auto gas used to. Expect to replace plugs more often, lead fouling is going to happen, unfortunately.

 

[HKCooper44]

Not to mention that AvGas can be $7 or more per gallon! But, it will keep in storage much longer than convoluted auto gas!

 

[tkhoffman]

I can lift hood and reach the switch I added.