Help! Tractor starts then dies

[Pattyb 8]

Hello,

We just purchased a GT550 with 475 hours from a friend. I ran it out gas my first time out and now it will start, run a few seconds and die. All symptoms pointed to clogged carburetor so today my husband drained and cleaned the gas tank, replaced the fuel pump, fuel filter and carburetor. I was sure it would run after all of that be we are still experiencing the same issue, starts, runs a few seconds and dies. Can someone suggest something else to try? 
Machine is a GT550 with a Kohler CH22S engine.

Thanks in advance!

Patty

 

[Maz91 260]

Does that have a vented gas cap? Im pretty sure a failed gas cap can put the system under vacuum and will result in starting and then dying out. Could be wrong though. Probably could test that by running it with the cap off. 

[Pattyb 8]

Yes. I did try running with the cap off, same thing, starts, runs a few seconds then dies.

[953 nut 59,984]

You may have some air trapped in the fuel line that the fuel pump can't move. Use a step by step process starting at the gas tank, close the shut off valve and remove the fuel line to see if fuel will flow from the tank when the valve is reopened. Attach the hose and move to the engine end, remove the hose from the fuel pump and lower it into a container to verify that fuel is flowing to the pump. Presuming fuel can make it to the pump remove the pump's outlet hose and turn over the engine to be surer the pump is functioning properly. If the pump isn't working look closely at the connections, there is an INLET and an OUTLET on the pump.

[gwest_ca-(File Mod) 11,482]

Believe a GT550 is a 522xi in 2005

[Handy Don 14,062]

22 minutes ago, gwest_ca said:

Believe a GT550 is a 522xi in 2005

Or a nice Suzuki road bike!

[lynnmor 7,817]

 

Does your carburetor have a solonoid that shuts off the gas when the switch is turned off?  If so, it could be faulty or the ignition switch or wiring may be the problem.

[oliver2-44 10,715]

Did you also replace all the fuel line? 

[wallfish 18,091]

is it only running a few seconds from just a squirt into the carb?

Sounds like @953 nut is correct on the vapor lock issue if it's starting on just a squirt into the carb and dying. 

[Pattyb 8]

Good morning,

My husband said he checked for air in the line by removing the hose to the carburetor and turning the key to on and gas was flowing through. 
 

No, he did not replace all the fuel lines.

 

Yes, this carburetor has a solenoid and there was a new one on the new carburetor. 
 

We do not need to spray starting fluid in the carburetor for it to start. It starts right up then quits. This machine wants to run! I have tried to keep it running by spraying starting fluid in once it’s starts but it still quits.

 

Question: Should the solenoid still have power when the key is in the run position? Can someone suggest ways to test the ignition switch or other electrical issues that might cause this problem?
 

I really appreciate all the thoughts and ideas. My husband has thrown up his hands so I think I am on my own now. I have done some carb cleaning for tillers and small lawnmowers so I am not a complete novice just inexperienced with electrical issues. 

 

Thanks again!

patty

 

 

[Gasaholic 294]

1 hour ago, Pattyb said:

 

 

Question: Should the solenoid still have power when the key is in the run position? Can someone suggest ways to test the ignition switch or other electrical issues that might cause this problem?
 

 

 

Depends but on a CH22 Kohler command, yes solenoid should have power any time key is on - It is an anti-afterfire solenoid, it shuts off fuel to the Main jet circuit of the carburetor to help prevent fuel getting through carburetor when engine is shut off (it's that fuel loading with no spark while engine coasts down to a stop that can build up in hot muffler causing backfire) 

 

Common sequence when solenoid doesn't operate correctly (or loses power) is, engine will fire up and run a couple seconds then die off like gas was shut off - Some engines (Since they run off idle circuit under governed idle) can be run at DEAD IDLE (That is, throttle all the way to idle and keeping the throttle on carburetor closed up against the idle stop screw) even under a solenoid failure. but once they come off idle, there's simply not enough fuel to run so engine dies out. 

 

  You want at least a test light to check voltage at the solenoid hot wire on the carburetor while going through start and run, if it loses power (light goes out) at any point, then likely you have a switch or electrical issue.  However a test light can give a false positive reading, if battery voltage drops too low at the solenoid (below 9 v) due to poor grounding or bad wiring connection, so a DMM is more useful to check that you have the full 12v (or up to 14.8v when engine's running) at the solenoid.    Poor grounds can cause a host of other issues as well, as can corroded, fatigued or loose wiring connections (Not uncommon to have failures at wiring connectors causing elusive "gremlins" in electrical systems that go away or return when harness or connectors are wiggled aggressively)  So if you lose voltage, most common issue outside of a failure in the wiring harness, is a bad key switch. (I have had more than a few of those failures) 

 

 

[Handy Don 14,062]

Just thinking of something simple. Maybe there is power to the coil when the switch is in START position but not when it is in the RUN position? That would let the engine start but not keep running. 

I’d check the wiring at the ignition switch and confirm that the connection to the R terminal has power when the key is in the Run position. If not, probably a busted ignition switch (since it IS getting power to crank the engine). 

Do you have a test light or volt meter and know how to use it?

Edited July 18 by Handy Don

[lynnmor 7,817]

Follow thru with what Gasaholic posted.  My guess is that you replaced the carburetor with a cheap Chinese one, if so all bets are off.

[Pattyb 8]

On 7/18/2025 at 3:50 PM, lynnmor said:

Follow thru with what Gasaholic posted.  My guess is that you replaced the carburetor with a cheap Chinese one, if so all bets are off.

There are expensive Chinese carburetors? 😀

Edited July 21 by Pattyb

[Pattyb 8]

Good morning!

I wanted to say thank you for all your help and suggestions. 

I sorta know how to use a voltmeter and planned on watching some YouTube videos but hubby was away and I couldn’t find the DMM so I was out of luck.
 

it is a power issue. Today my husband was trying to sort it out and I suggested running a temporary wire from the battery to the solenoid. Tractor starts and runs!

It’s either the switch as Handy Don suggested or a relay. My next stop is to review the wiring diagrams to find the relay(s) and trace the wires. As I type this, I am remembering my friend’s handyman said he cleaned out some mouse nests this spring and I wonder if a bare wire is grounding out. I was on some rough gravel when it died and assumed I ran out of gas which led to thoughts of clogged jets….

 

Thanks again for all your help and suggestions!

patty

 

 

 

 

 

[gwest_ca-(File Mod) 11,482]

 

[953 nut 59,984]

Your fuel solenoid has two sources of power, one is from the ignition switch in the start position and the other is from the engine's charging system going through a diode. This is a safety device to shut off fuel flow if the engine isn't running.

If the charging system is not functioning or the diode is bad the solenoid will close as soon as you go from start to run on the key switch. The fact that everything worked well with a jumper wire proves that the problem is probably the diode or the wiring to or from it.

I do not own this model so can't be of any help in locating the diode, just follow the purple wire and you can locate it.

 

[Handy Don 14,062]

1 hour ago, 953 nut said:

he fact that everything worked well with a jumper wire proves that the problem is probably the diode or the wiring to or from it.

If the problem is fuel, then this is a good bet.

If the problem is electrical, then it still could be a bad R terminal contact on the ignition switch, which is pretty easy to test. 

[Pattyb 8]

Good morning!

I have a new ignition switch in the mail. I tried to buy one over the weekend at the hardware store but it’s not a stock part for them. I am hopeful it will resolve the problem and I don’t have to deal with replacing a diode. 
 

Thanks for the schematic! It will be very helpful if the switch isn’t the issue.
 

I did examine a lot of the wiring for chew marks and didn’t find anything but a mouse nest in the boot of the steering column. I did find a wiring connection up by the fuses that is not connected to anything. It has some electrical tape on it. Is that for accessories? I did not see anything in the owner nor service manual.
 

I will post back after we replace the switch so that the next person has information on what to try next with troubleshooting.

 

I wanted to thank all of you for your help. We have never worked on a carburetor with a solenoid so this was new for us and my research led me here and I am glad it did. You are a wonderful group of people and I’m glad I found you!

Pat

 

 

 

[Lane Ranger 11,395]

I had a similar problem with a 701 Wheel Horse tractor  that would die after running for thirty minutes.  Not a gas/fuel line or v=carb issue but turned out to be a bad ignition switch.  The three prong switches made today may not be as well made as I have had two fail.  Not sure if they were a Cole Hersee switch (usually the best) or a knock-off but one of the prongs broke connection as I found out after taking the switches apart.