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18hp Command powered sovereign no start


jimmystractor

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I feel like it may be something dumb like a wire or something. I have a 18hp Command powered Sovereign. It has been running great with no problems. I went to start it today and it turns over great but won’t start. I checked the wires under the seat and they are intact. I took the air cleaner off and shot some starting fluid and there was no change....cranks great but no start. I used a spark checker and have spark at both plugs. Any ideas on what to check next?

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Spark...no start...fuel ? You would not have spark if seat or safety switch was bad. 

Loosen the nut on bottom of carb a few turns to be sure your getting fuel to the carb...if not...fuel filter or fuel tank obstruction.

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24 minutes ago, Alltractoredup said:

fuel shut off solenoid stuck ? will the shut off solenoid block fuel sprayed directly into carb?

If carb is equipped with selnoid shutoff. ...that also could be the issue...wire could be off or broken at the carb bowl.

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Maybe I am confused but wouldn’t it have started for a second or two when I sprayed  some starting fluid down the carb when I was trying to start it if it was a fuel issue?

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2 hours ago, jimmystractor said:

Maybe I am confused but wouldn’t it have started for a second or two when I sprayed  some starting fluid down the carb when I was trying to start it if it was a fuel issue?

Not if carb is or was flooded

Did you have any recent backfire issues? It may be a sheared flywheel key. Timing could be off.  It would not fire on starter fluid if out of time.

The suddenness of the symptoms is what confuses me.

Edited by fishnwiz
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Before I'd look for another issue, I'd make sure it's not a fuel issue.  It's a lot easier to do as a first step.    

I'd make sure the fuel is getting to the carb and the fuel solenoid is working.  Here's a couple of pics showing the fuel solenoid location:

IMG_8337.thumb.JPG.f5ebba83456eeaf4f259a0c5d921bba8.JPG

IMG_8360.thumb.JPG.189d37d94ef22a929779512a4ab1f43e.JPG

You can get to it from above (as shown in 2nd pic) after taking the air filter and housing off (Close the choke plate before you start and make sure there's nothing around that can fall into the carb).  Disconnect the connector (red in the pic) and apply +12v directly to the solenoid from the battery - when the +12v is applied you can probably hear it click (If you're not half deaf like me).  See if the engine will run.  If it does, you've found the problem (wiring issue or bad fuel solenoid). 

If it doesn't run, disconnect the fuel line at the carb and crank the engine and see if fuel is being pumped to the carb.  If it isn't, then the fuel pump or plugged filter or line is the problem.  

If you have spark and fuel, then it's something else as suggested above.  

 

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No recent backfire issues. Nothing out of the ordinary. I will take the fuel line off and see if I am getting gas to the carb.

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I would think it should pop, run a few seconds, etc. if you pour a small amount of fuel into the carb throat.  Like at best a half of a shot.  I put the air cleaner cover back on always in case of backfire.  But that is how I test engines to see if they even might run.  Spark?  Check.  Fuel?  Check.  Compression?  Check.  If all of that is in place there is no reason they should not start and run..............except, as stated, a sheared flywheel key.  

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I had some time today to mess with it. It still will not start. I took off the air cleaner and pulled the full line to the carb...I turned the motor over and gas was coming out of the line so it appears it is getting fuel. On a side note I always run premium fuel with no ethanol.

I did a compression check. I had around 148 on one cylinder and 120 on the other.

I went to the parts store and got some new spark plugs...put them in and still no start.

One question in regards to having spark. I used a Lisle brand spark checker. When I was testing to see if I had spark, I did this with all the lights turned off and could see I was getting spark with my tester. Is there such a thing as having spark but not “enough” spark to start an engine? I thought is was odd but then took the spark tester on my Stihl leaf blower, which is a pull start. It was the same amount of spark with that as with my tractor. 

I’m not sure what to do next. The wires seem fine. It is getting fuel and appears to have spark. It turns over great. It just won’t start.

 

 

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Find somebody your not a big fan of and have them hang onto the plug wires one at a time as you crank it over. If it knocks them to the ground....well you have good spark. Short of finding this much dis-liked candidate....see if you can lay the spark plugs against the cylinder and crank it over. Should have a good blue spark with a bit of a snapping sound. I really prefer asking someone to hang on to them tho......Always seems to have better results!!!!

Harry

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43 minutes ago, jimmystractor said:

Is there such a thing as having spark but not “enough” spark to start an engine?

Yes there is.  I use the same testers as you & I use two at a time to check to see if both test bulbs are equal brightness.  I'm not thinking you have a coil problem yet however.  I can see one of them going & creating a "missing" sequence but for both to go at the same time seems a little strange to me. 

I'm thinking this is carburetor related since the fuel pump is working. 

When you remove the air cleaner, pull the choke & check the tension on the butterfly.  If the spring is weak & will not hold the choke COMPLETELY closed, your engine will NOT start no matter how much fuel & carburetor cleaner you spray in it. 

While cranking the engine over, close the butterfly completely with your finger, if it fires, that is the problem.

If this is the case, you can purchase a choke rebuild kit for it.

Edited by ShaunE
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I just checked this. It is closing when the choke is applied. I also pushed down on the butterfly while trying to start it. 

 

One thing in relation to this...this motor has always been one where you have to have to the choke applied to start it...even when it is warmed up. I do have another command powered sovereign here. Should I pull the carb off of that one and put it on the troublesome motor and see what happens? Or is that a waste of time?

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Not necessarily a waste of time. 

There are a few different sized O-rings inside of that carburetor between the fuel shut-off valve & the emulsion tube that may have degraded.  I guess I'd pull it off & take it apart & inspect all pieces.  Including running a torch tip cleaner through all of the small passages in the body & emulsion tube even if they appear to be open. 

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If you cannot get it to even pop, with new, dry plugs, and after dumping some fuel in the throat of the carb, I do not believe it is a carb issue.  It should fire, and then, if the carb isn't working to supply fuel it will die.  If it does not even pop, I sense a poor spark or sheared flywheel key, where the timing is off so badly that it will not even hint at starting.

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If you have good fuel flow, good spark and good compression, it sure should at least pop and  run for a few seconds when dumping fuel directly into the carb. Sure is sounding more like a timing problem.

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i am folowing this as i have the same problem!!! mowed and parked and shut off and will not start!   replaced plugs a couple of weeks ago, checked fuel supply, removed fuel shutoff to check and reinstalled, replaced ign switch incase it was corrodded inside, now trying to determine which wire powers the coils and will try to run a wire from battery to coils to see if thats the problem, (thats why I replaced ign switch - i assumed mabe the coils wernt getting power)   i can turn the switch and it will crank over and i spray ether into carb throat and dont even get a POP?!?!?!?!

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If we are talking the command engine in both cases here, there is the possibility that it is a lifter or valve not opening/closing properly. But I would be checking the flywheel key first. I had, well actually still have, an old Ranch King out at the cabin. It would not start most of the time yet it had fuel and spark. It too would not even fire when putting gas or starting fluid into the carb. It would spit gas back out the carb.  I had even replaced the plugs, ignition coil module, fuel pump diaphragm, filter, cleaned the carb and even installed a larger battery with heavier cables. This thing would run great once started and had lots of power. But the no start problem continued. Now this tractor has the flathead Briggs twin but valves work by the same principle whether it has hydraulic lifters or not. Anyhow I finally removed the heads and decarbonized and did a valve adjustment. Now she starts. So in the case of the Command engine, there could be the possibility that lifters or worn rockers might be contributing to the problem and it could be over filling or filling the combustion chamber at the wrong time and the fuel is not getting ignited. That's kind of how it was explained to me at the time.Just throwing it out there.

Edited by puttputt
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I won’t have an update for a couple of weeks, sadly. I am going to drop it off at a small engine guy but he is on vacation until the 24th of Sept. I will report back.

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Sounds like a problem similar to a Tecumseh on a mortar mixer I repaired lately. Mixer was hard to start, but always did, until it didn't. The problem description I got was that he had to pump the primer sometimes 5, 10, or more times to finally get enough fuel to start. After that, it ran fine until stopped, then same problem all over again. It is overhead valve, as I think your engine likely is (I am not totally familiar with late model Kohlers). I repaired the leaking bulb, then adjusted the valves back to the .004 spec. Now, pump the bulb 2 times, it starts on first pull. I have a Kohler Courage, aptly named...it takes courage to use it before something else breaks...The intake valve was .003 out, exhaust .005 out of spec. You could not start that engine at all. Sounded like it was going to start, hit, sputtered, never started. I was about to check the key, but checked valves first

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On 9/5/2018 at 4:40 PM, lugnard said:

Find somebody your not a big fan of and have them hang onto the plug wires one at a time as you crank it over. If it knocks them to the ground....well you have good spark. Short of finding this much dis-liked candidate....see if you can lay the spark plugs against the cylinder and crank it over. Should have a good blue spark with a bit of a snapping sound. I really prefer asking someone to hang on to them tho......Always seems to have better results!!!!

Harry

I know the candidate!! Problem is, he seems to enjoy it. I remember when I was young, his favorite way to shut an engine off when he was working under the hood, was to simply stretch his hands out across the plugs and ground them out. In the old days, plug wires did not have rubber boots on the plugs

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5 hours ago, MrSteele said:

I know the candidate!! Problem is, he seems to enjoy it. I remember when I was young, his favorite way to shut an engine off when he was working under the hood, was to simply stretch his hands out across the plugs and ground them out. In the old days, plug wires did not have rubber boots on the plugs

 

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Now that reminds me of ...well the old days and I'm only?? 63. But when I was much younger and working on my car ,there were always a few older guys that knew everything and I do mean everything. They were the internet before it was even thought about! If you couldn't figure it out that's the guys you went to.....I miss those guys!!!! Anyway this guy in particular was one of those that could hang on to plug wires and tell you if you had a bad cylinder. I almost fell for it a couple of times but he would want to grab your hand and of course you would be the one knocked to the ground.....ah the good 'ol days!!!!!

Harry

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