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docs

Sunstar V-Twin Kohler 20 Wont Start

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docs

I have a V-Twin ! am working on that will not start unless you poor gas in carburator, and then you can see the inside butterfly of the carb flapping. First im gonna check the pump and filters then I think might be a valve problem but would like some input to make sure before I tear into it.

Thanks

Doc

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docs
quote:Originally posted by PhanDad

If your V-Twin is like later models, it has a fuel shutoff valve. It might not be opening. Could be as simple as a broken or unhooked wire.


id="quote">
id="quote">I think it is a 89 model looks like the kohler command and not the magnum, Guess I should chase the numbers down and find out. I am working on it for a friend that knows a lot less then I do about these sunstars and the twin engines. It has a dead battery right now and I'm currently charging the battery. But the filter is good, I blowed air back into the tank make sure its not plugged there. Gotta get it turning over to see if pump is working yet. I'll go from there, any idea where the fueal shut off might be. It has the rotary pump on it with the looks like vacum assist. Also there dont appear to be any power going to the starter at all. PTO and Seat lights come on when you turn the key on. We jumped it at his place and poored gas in the carb to start it.

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PhanDad

The fuel shutoff is by the carb, on the flywheel side. It's at the top of this pic with the red w/white trace wire going to it.

IMG_8337a.JPG

It needs power in both "start" and "run" modes. The Command wiring diagram:

Command_Connector_Diagram1a.jpg

If the starter not getting power, then neither is the fuel shutoff. Depending on how you're jumping it, the fuel shutoff might be getting power.

IMG_8337a.JPG.48eeb8732e516b6d6845c580b6ae4bb9.JPG

Command_Connector_Diagram1a.jpg.c97de1e4eee0fca0d2bfa2b3eb9f81a5.jpg

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OK yes I have located it and the wire is hooked up, But now I'm thinking it's not getting enough fuel also, Funny thing with the ignition on this tractor once you get it started the starter keeps running and you have to shut the ignition off and it will run until the gas I pored in it runs out. I think you might be right it's not feeding the gas #1 because you have to shut the ignition off. It is the Kohler Command 20 Ch20S.

Someone has some wires crossed or keyswith is bad, Maybe the silanoid. I'll have to use that diagram and chase the wires. thank you for posting that. it will be a big help.

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docs

OK I figured out that once I bump started it with gas and started it if I turn the key off to stop the starter from continuing to run and turn it back to run position it will run all day long. When you shut it off it delays for about 3 seconds before it will turn off. Sure does sound like a keyswitch problem.

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PhanDad

The engine connection plug should be something like this:

TractorPlugCommand2a.jpg

The dwg is from Al Eden for my install of a Command into a Sovereign.In the "run" condition, pin 2 should not have power or the starter will continue to run. (Or you may have a starter pinion disengagement issue.) When running, as long as the alternator/rectifier is working OK, the engine will supply power to keep the fuel shutoff valve open (pin 3). Pin 3 also usually supplies current back to charge the battery (via the ignition switch). And in the first diagram, the "Ignition Module Input" is the "kill" ground connection.

TractorPlugCommand2a.jpg.6b7dbef4f6853d84a0092e690e47aebd.jpg

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I found the model it appears to be a 92 model with part number 1692133 or a 1692135. the model sticker is gone because it was repainted and instead of taping it off they removed it. Butt the owner has a book and model from a rebuild on the engine where the previous owner did a rebuild on the motor and repainted it. They apparently got some wires crossed, I found a diagram on simplicity site and gonna chase the wires today to see what they did. I guess they got confused about the fuel shut off solenoid and jumper'd it into the starter somehow.

I wonder if these sunstar tractors had key switch issues because my 14hp kohler sunstar has issues with it trying to start when you turn the key to lights, It turns the starter over.

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docs

OK so I found a added terminal box going to the starter and and there was a blue wire that was jumped into that terminal that also fed power to starter. when I pulled the blue wire from that terminal box the starter quit running after the tractor starts like it should.

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docs

Im having no luck finding the starter group and wiring for the starter wire and there's a connector block around the starter with several wires coming out of it with blue wire tapped in with the red, Where does that go?. anybody have a image of that? it is for a 1992 Sunstar kohler ch20s with power steering and hydro with differential lock. 1692133 and 1692135 models.

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PhanDad

Look at the first wiring diagram.

I don't know if your wire colors are the same, but my 2 Commands wire colors are as shown. I drew in the blue wire that goes to the starter from the engine end of the connector.

Note the diodes in the red wires that go to the carb solenoid (fuel shutoff). They are to prevent back feed of the +12v that energizes the carb solenoid.

If the diode is shorted in the red wire from the "Starter and Carb Solenoid" terminal, then voltage from either the rectifier or battery can back feed the starter.

The wiring I'm describing is for a Sovereign. I would think the Sunstar is similar.

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docs

OK That makes sense, That sounds like that is what is happening, I'll check the diode for ohms and try determine if its bad. Wright now I have pulled that blue wire and everything appears to work as it should.

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PhanDad

Found a wiring diagram for your tractor. It's in the 1993 Electrics Manual. The Sunstar wiring is very busy, much more than a Sovereign.I've cropped a section from the "Cranking" diagram that shows the wiring around the engine connector plug. It's as I described above.

CrackingCircuit_EngineConnector.JPG

For the tractor end of the connector wiring, the red wire connects back to the battery thru the ignition switch for +12v from the engine rectifier. The blue wire is the "kill" wire to shutdown the engine. The orange wire is the "start" wire from the tractor starter solenoid. The unlabeled wire (runs to the right) is green for the low oil pressure light. If you want an electronic copy of the Electrics Manual, PM your email address and I'll send it to you. It's too big for Club email.

CrackingCircuit_EngineConnector.JPG.55c82ba4258336512b3e5f92619153d5.JPG

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OK lot better understanding of the wires now. They have a violet wire hooked to a terminal on the starter, and what I can see just a red/w wire to the fuel solenoid. There is a white wire that connects to nothing I believe it is a kill switch wire that is not hooked up. the blue wire comes out of the terminal block connector was going to the the red with the starter. I am gonna have to find that diagram for the sunstar just to make sure they have not changed any wire colors, my 85 sunstar with the kohler magnum colors are completely different.

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OK I think i see the problem, they have the violet wire going to the starter and the blue wire both. The violet is suppose to go to the fuel solenoid and the blue to the starter.

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OK I think i see the problem, they have the violet wire going to the starter and the blue wire both. The violet is suppose to go to the fuel solenoid and the blue to the starter.

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PhanDad
quote:Originally posted by docs

OK I figured out that once I bump started it with gas and started it if I turn the key off to stop the starter from continuing to run and turn it back to run position it will run all day long. When you shut it off it delays for about 3 seconds before it will turn off. Sure does sound like a keyswitch problem.


id="quote">
id="quote">From the above comment, the "There is a white wire that connects to nothing I believe it is a kill switch wire that is not hooked up" and your last post, it sounds like the PO wired it so the fuel shutoff solenoid would be the "kill" method.It's an interesting idea, assuming the engine runs until it completely empties the carb of fuel, this would prevent gas from turning into gunk in the carb. Not sure if about 3 seconds is enough time to completely empty the carb, but maybe the Command carb doesn't hold too much fuel.

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docs

Well I found that it works good the way it is, don't mind the few seconds it takes to shut off. If I hook it up the way it is suppose to be it does not seem to shut it off any quicker. If I hook the blue wire to the starter it does not start. I found that they had put a new fuel solenoid on the tractor and it only has 1 wire feeding it. According to the diagram there are 2. Pink/white, and Violet. So I'm guessing that the new solenoids may have just 1 feed??? lol.

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I returned it to the owner and he is happy with it. so gonna leave it the way it is. Thanks everybody for the help especially PhanDad. I need help with my sunstar with a 14hp Kohler magnum. No governor when climbing my hilly land and the RPM's raise when going downhill. but that's another thread.

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