Kohler Mag 20 dumping fuel again

[mpatterson]

So my Mag dumped the gas into the base of the engine again - you think I can remember what I did to resolve this problem last time??? I can't seem to find the post on here where you guys helped me with the issue either. I'm guessing something stuck in the carb to allow fuel to dump? I had installed a in line shut off before but stopped using because I had forgot it turned on one day and nothing bad happened. yeah that stopped the other day! I have the plug out of engine letting the gas drain and evaporate. I'm guessing I'll have to change the filter as I don't know if this happened while driving it. Last time it was used wife was collecting stuff in yard, so stopping and starting was involved. It may have happened over night while sitting too?

 

[jkoenig]

Is this the thread you were looking for?

https://www.ihcubcadet.com/threads/kohler-mag-18-1872-tractor.7481/
I noticed in other threads that you also have replacement fuel pumps. You might want to look into if they can overpressurize under any conditions (start/stop that you mentioned?)

Good luck, and let us know how you make out.

 

[tkhoffman]

Probably gas is getting passed the needle valve seat in carb. If the needle valve has the soft rubber tip, I would suspect it got hard from the ethylene gas. That gas is tough on carburetors.

 

[mpatterson]

Probably gas is getting passed the needle valve seat in carb. If the needle valve has the soft rubber tip, I would suspect it got hard from the ethylene gas. That gas is tough on carburetors.

Thinking it has a needle with rubber. Been a while since I had carb apart.
Was hoping I could change oil and filter and use tractor. Need to plow garden when rain rakes a hike. Will have to use the shut off valve when tractor not running until I have time to get either replacement needle or change out carb worst case.
Been using high test gas in all my small engines lately because I was having issues with gas before, Gumming things up on me in the past.

 

[Neil Mullins]

In most cases even high test gas has alcohol in it. There is still a few places you can get ethanol free gasoline. Closest place for me here in central WV is a bit over 1 hour drive 1 way. I resort to using a gasoline stabilizer. Sea foam, sta-bil, etc.

 

[Ken Black]

In most cases even high test gas has alcohol in it. There is still a few places you can get ethanol free gasoline. Closest place for me here in central WV is a bit over 1 hour drive 1 way. I resort to using a gasoline stabilizer. Sea foam, sta-bil, etc.

did you watch taryls utuber channel.... just sayin.....

 

[mpatterson]

I used sea foam before and wow did it cause problems! Cleaned things too good on my old stuff. I stopped using it because I was having so many problems.
Its tough when things are getting worn out what to or not to use as additives

 

[Neil Mullins]

Hard to argue with the Taryl UTube video on fuel additives video. At the same time I began using fuel stabilizer, I also began closing fuel valve & letting engine consume gasoline in fuel bowl. (Run till engine dies) then top off gas tank to full. That leaves very little air space for tank to “breathe” in air & moisture to react with the ethanol. Mixed fuel engines (chainsaws, weed whackers) dump & dispose of what’s left in tank, restart & run dry.

 

[eholmes]

I guess we live in a good area for fuel. We have two scources of 89 to 91 octane alcohol free. Stewart's and All Fresh. Oh upstate NY. Also if you like ice cream I'll rate Stewart's above Bryers and Ben and Jerry's. I use a shut off on my 682 and have replaced the needle valve. I have done a little research and I'm going to replace the diaphram in the fuel pump.

 

[dgeary]

I used sea foam before and wow did it cause problems! Cleaned things too good on my old stuff. I stopped using it because I was having so many problems.
Its tough when things are getting worn out what to or not to use as additives

Interesting. I've used Sea Foam for years on all my stuff and have never had any problems. And I've got a lot of older vehicles/small equipment. I'll use that over anything else I've ever tried.

 

[tkhoffman]

Thinking it has a needle with rubber. Been a while since I had carb apart.
Was hoping I could change oil and filter and use tractor. Need to plow garden when rain rakes a hike. Will have to use the shut off valve when tractor not running until I have time to get either replacement needle or change out carb worst case.
Been using high test gas in all my small engines lately because I was having issues with gas before, Gumming things up on me in the past.

That's what I would do. Change oil, use shutoff. I do that on my cub. Put a shutoff where I can reach with the sides on.

 

[mpatterson]

That's what I would do. Change oil, use shutoff. I do that on my cub. Put a shutoff where I can reach with the sides on.

Pretty sure that will become my new practice. Check oil and turn on gas. And shut off when done for day. Not really up for doing a carb job now. Have to finish snow blower rebuild before snow flies

 

[jerry.a.johnson]

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.

 

[jbland]

needle and seat or bad float

 

[Ken Black]

I guess we live in a good area for fuel. We have two scources of 89 to 91 octane alcohol free. Stewart's and All Fresh. Oh upstate NY. Also if you like ice cream I'll rate Stewart's above Bryers and Ben and Jerry's. I use a shut off on my 682 and have replaced the needle valve. I have done a little research and I'm going to replace the diaphram in the fuel pump.

at 3.55 a gallon for the cheap stuff ughhhhh..... i run around 10 gallons a week................... rouses point... there nilla ice cream and coffee ice cream is good tho i admit to that lol ...

 

[HKCooper44]

I experienced "gas dumping" for the first time on my Cadet 782 with the KT-17 engine. When I went to start it, tte engine turned about half a revolution and locked up. I removed both spark plugs, and hit the starter, and an ocean of gas shot out of the righthand cylinder in my face. I put the plugs back in, started the engine, and mowed for about an hour. When I was finished, I installed a Briggs fuel shutoff valve in the fuel line just before the pump, closed the valve, then ran the engine until the carb bowl was empty. I have to assume that the carb needle/seat is screwed up, and leaks fuel by gravity when the fuel tank is more than half full.

 

[gary noblit]

Coop, I'm thinking you got lucky.Any spark at all would have set you and the mower on fire instantly.I'm preaching from experience.The wisest thing to do is turn the engine by hand with plugs out,that will get most gas out then let it set for an hour or so with plugs out.The issue of gravity tanks is simply a safety factor to put shut off in fuel line.The industry has got away with this very unsafe situation for many years.Consider this ,consumers are betting that tiny thing called a needle is never going to fail but when it does it's a dangerous thought.It might lead to a garage fire or house or barn all based on a needle valves condition.This is why newer machines have a solenoid on carb that won't allow fuel to flow unless key is on and shuts fuel off when key is turned off so no more backfire.. but I still believe in shutoffs...

 

[HKCooper44]

I didn't mention that I'd pulled the plug wires off at the coil!

 

[gary noblit]

Coop...smart move...

 

[MarcHeld]

I experienced "gas dumping" for the first time on my Cadet 782 with the KT-17 engine. When I went to start it, tte engine turned about half a revolution and locked up. I removed both spark plugs, and hit the starter, and an ocean of gas shot out of the righthand cylinder in my face. I put the plugs back in, started the engine, and mowed for about an hour. When I was finished, I installed a Briggs fuel shutoff valve in the fuel line just before the pump, closed the valve, then ran the engine until the carb bowl was empty. I have to assume that the carb needle/seat is screwed up, and leaks fuel by gravity when the fuel tank is more than half full.

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.