# Engine only starts at idle.



## Country Boy (Mar 18, 2010)

Just wondering if anyone else ran into this before. I've been dealing with a few Kohler Command single cylinder engines that will only start with the throttle lever at idle. You can choke them and crank all day and they won't start, but if you move the lever to idle it will fire right up. They run perfectly fine once started. I've tried cleaning carbs, adjusting the choke linkage, replacing gaskets, and more. These engines are all older, most around 10-12 years and have maybe 800-1200 hours on them.

Its not a major issue, and only a few people have mentioned it, but I notice it on several units I work on regularly.


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## jhngardner367 (Apr 5, 2011)

I've had the same thing happen with the K-series,on the Bolens,and the CV460s,on the JD.
I ended up cleaning the breather assembly,really good,and it cured it.
I think it has to do with the amount of vacuum,while rolling over .Or,maybe it just made the fuel pump (both vacuum types)work better.
On the other Kohlers,with mechanical pumps,one a KT series,and the other a K series,I could only get them to start above idle,if I ran a wire to the coil,directly from the battery. At idle,they started fine.
I changed the condensers,coils,etc. no change.Then,I replaced the plug wire,with an 8mm copper core,and it cured it.
On the newer ones,with the pointless ignition,I've found that sometimes the compression release sticks(when equipped),and also,if they have the carb solenoid,it's more prevalent.Never figured out why,though .


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## Country Boy (Mar 18, 2010)

I've been wondering if it has anything to do with the coil. At idle, the throttle plate is closed and the engine is taking in less air, thus making the compressed charge less dense, thus requiring less voltage to jump the gap on the plug. I got a good spark on the spark tester, but it was more white/yellow than blue/white. It was a nice, wide spark with a good kick behind it, though. As it stands now, the unit I was just working on now starts if you crank it with the choke fully activated for a second or two and then drop the throttle to full throttle to deactivate the choke. Do that and it'll pop right off. Still won't start with the choke on, though.

Another thing I wondered about is all of these units have that semi-automatic choke system on them that Kohler had. The choke shaft has a spring built into it that allows the choke plate to open somewhat after the engine starts. Thinking back, I don't think any of the affected engines had just a standard choke shaft on them. The choke plate was closing fully when the lever was in the choke position, though.


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## jhngardner367 (Apr 5, 2011)

Try tis: Put the choke on,normally,and as it rolls close it,with your finger. If it starts right up,the choke may need an adjustment.


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## Country Boy (Mar 18, 2010)

I had checked the choke adjustment. With the lever in the full choke position, the choke linkage is moved as far as it can go. I tried moving it farther with my hand, but it was tight (i.e. fully closed).


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## skunkhome (Nov 30, 2008)

When cold both my 320000 series Briggs and my K341 start best at idle or with throttle slightly cracked. My brother who is 200 miles away has a 716 AC with a Briggs 320000 series and has been complaining that he cranks and cranks and it tajes forever to start. At my direction he has cleaned points, filter, changed fuel filter, plug and made adjustments to the idle fuel needle. There was some improvement but not much. I was concerned as he is not mechanical at all and I knew a carb overhaul was out of the question. Then he mentioned that he had the throttle wide open. I told him to try cranking with throttle closed and it cranked right up. He had been complaining of hard start since February 2013 when he got the tractor. He previously had a sears with a 20 or 22hp v twin that he always cranked at full throttle.


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## jhngardner367 (Apr 5, 2011)

I think some of them are just tempermental. 
Although,I did work on one for a customer,that had starting/running problems,that he said began when he moved to Michigan.
On a hunch,I changed the jets in the carb,and it straightened out. He lived in Denver,Colorado,and I presume the change in altitude caused it.
The carb wasn't the compensating model.


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## OldBuzzard (Jun 23, 2011)

jhngardner367 said:


> I think some of them are just tempermental. ...


I have 4 Bolens 1886s with the Kohler K482 in them and they all start a bit differently.

One needs full choke even on a 90* day, while another one will start at 32* with no choke. It has to start with no choke, and then just a quick open-close a couple of times until it warms up a bit. Keep the choke open too long and it dies.

Another one only needs 1/2 choke and 1/2 throttle, the last one, 1/2 choke and just a wee bit of throttle.

I've just learned to deal with their quirks.


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