Mower starts, but won't stay running

wolfsmane

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#16
Thanks for the replies. Keep in mind that I did clean and blow out the OEM carb 4-5 times with no improvement. Then, I bought a brand new carb, again with no improvement.

I will blow air throught the carb to see if gas comes out . And spray gas through it.

The fuel cutoff solenoid - on the OEM carb, I did replace solenoid with a new one. No improvement. Took the old solenoid and took the rubber tip off so that it couldn't block fuel. No improvement. New carb came with new solenoid. No improvement.

It is just strange that nothing I do makes ANY improvement. Not even a little bit.
 

grcauto

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#17
I have had to use air at 175psi on carbs right out of the box to get them to work. I put the nozzle of the air gun within a 1/4" of the jet and any other metering holes to get them to clear. Once you verify the bowl fill valve is free and filling with fuel there's nothing left but the venturi pulling fuel through the jet from the vacuum produced as air passes through. Your carb needs to be blown out.
The alternative fuel used to keep it running was gasoline like what you have in the tank....correct? If so, you need to boost the air pressure and get in that carbs face with it. I should say....into it's guts....
 
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wolfsmane

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#18
I have had to use air at 175psi on carbs right out of the box to get them to work. I put the nozzle of the air gun within a 1/4" of the jet and any other metering holes to get them to clear. Once you verify the bowl fill valve is free and filling with fuel there's nothing left but the venturi pulling fuel through the jet from the vacuum produced as air passes through. Your carb needs to be blown out.
The alternative fuel used to keep it running was gasoline like what you have in the tank....correct? If so, you need to boost the air pressure and get in that carbs face with it. I should say....into it's guts....

Thanks. I will have to check out my compressor to see how high the psi goes. I don't think it goes to 175psi.
 

grcauto

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#19
Even if it's 125psi it'll probably be OK. Just get the nozzle up close and personal with it.
 

grcauto

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#22
Not sure on this model but some had a screen inside tank on the fuel line
That reminds me. Pull the fuel line off and see the stream. Just a trickle or drip drip. Try this first. It always comes down to the basics. Well not always but many times we chase our tails and it's something as simple as fuel flow.
 

wolfsmane

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#23
Ok, had a few minutes to play with it. I took the gas cap off during everything below.

Fuel cutoff solenoid works properly.
Taking the muffler off and running, had no effect, still won't run past the initial startup.

Blowing air through the carb. I am not sure how much gas I should see coming out the other side...I did see an initial mist come through,
but beyond that, nothing major. I just pulled the carb off without disconnecting the linkages. When I first blew the air, a mist got the gaskets that were still attached to the intake, a little wet. Nothing major - like not soaked. I am guessing that I should have seen more gas, but am not sure.

Took the carb, flipped it upside down, took the bowl off, took the float and needle out, and blew air through every opening I saw. I am covered in gas now, LOL. But, I blew every hole out several times. I put the needle, and float back in, and closed the bowl. Attached all the linkages/spring.

Tried cranking again. No improvement. Exactly as if I did nothing at all. Choke it - it cranks right up, runs for 2 seconds and dies.

I also looked for any broken or frayed wiring and didn't see anything.

Time for a new mower, lol? I really have to learn to take better care of my stuff.
 

wolfsmane

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#24
Not sure on this model but some had a screen inside tank on the fuel line
I took everything off fuel system related. I took the tank out and cleaned it spotless. Installed a new grommet where the fitting comes out of the tank that attaches to the fuel line. That 90 degree fitting was cleaned, nothing inside, no screen or anything. Installed new fuel line, new filter (3 times).
 

wolfsmane

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#25
That reminds me. Pull the fuel line off and see the stream. Just a trickle or drip drip. Try this first. It always comes down to the basics. Well not always but many times we chase our tails and it's something as simple as fuel flow.
It is a stream. Every time I have taken the crab apart, the bowl is full. I had been placing the fuel line in a small bucket to catch the gas whenever I took the old carb apart (several times) and finally installed a cutoff valve.

The bowl always fills up quickly when reinstalling and only takes a quick moment to fill up enough to start.

But then it dies.

On another note - I found my really big hammer! LOL
 

billr

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#26
Did you try the "sanity check", see if it will keep running well-beyond the 2-5 sec. hurdle if you spritz gas into the intake?

That 2-5 sec is pretty quick, I don't think fuel flow into the carb or venting of the tank could kill it that quick. Same with float level, if it is too low it would have trouble starting and running, but not an abrupt kill after just a couple of seconds.

If you blow through the carb, the mist should continue and be just as consistent as the flow you are directing through there. The pressure side of a shop vac, or a leaf blower, should be consistent enough that you can "spray paint" fuel onto a sheet of card board until the fuel tank runs out. If the mist is quickly petering out, that is a big hint that the engine won't continue running either. How about some pictures of this carb and its innards, which holes you are blowing etc? Do you have a make and model number for it? I'm not sure what we can tell from that info, but we will have to keep picking at this from all sides!
 

wolfsmane

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#27
Yes, spritzing gas into it will keep it running.

The mower is a Husqvrana YTH20K46 with the Kohler Courage 20HP.

The carb is part number: 20-853-35-S --> https://www.ereplacementparts.com/kit-carburetor-p-1793758.html
The fuel cutoff solenoid pictured in this link is what the OEM solenoid looked like. Now, it is a stubby housing with a 2-wire connector, that replaces the 1-wire that the original had. Yes, I thought that maybe this new solenoid was a problem, and replaced it with the old 1-wire solenoid with no improvement. I even took the rubber end off of the fuel cutoff solenoid so that it couldn't shut off the flow of gas, with no improvement.

I will try and post a video of how it starts and stops, soon.

It will be a couple of days before I can tear it apart again. I have 4 ruptured discs in my lower back and can only do limited things, and tomorrow is filled with replacing bunk boards on the boat before the cold weather decides to visit. I will probably be down for a day or two after that trying recuperate.

I appreciate all of y'alls help and patience.
 

billr

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#29
I gotta ask, since the first link shows the carb upside-down... it is mounted on the engine with the bowl and solenoid down, correct?