Hard Starting Cold Kohler Generator

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  #1  
Old 02-03-07, 11:31 AM
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Question Hard Starting Cold Kohler Generator

I have a Kohler 12 RES automatic standby generator, new in July 2006 with a total of 7 hrs on it. Runs on natural gas. Gas delivered at a stepped up pressure of 11 inches water column going 120 feet from gas meter through 1 1/4 flex piping. (Specs. call for 7-11 in.) That is to say, no problem with gas delivery to the generator regulator. When running, runs great.

When trying to start at temps below freezing (several attemps at about 6 deg. F or even at 26 degrees) it wont start. Strong 786 CCA battery. Three cycles of 15 seconds cranking...no go. Applying a little heat with hair drier or just leaving a 100 watt trouble light sitting by the carburetor for an hr (getting the nearby air temp to 34 deg F) results in it being able to start in less than 3 seconds of cranking and it runs great.

My question is about what is really causing this engine (Kohler CH740EP 725 cc 20.5 HP with electronic governor, 3600 rpm and factory fresh spark plugs)and clean air filter) not to start.

Is it related to condensing water vapor from the natural gas, then freezing and preventing movement of throttle plates or blocking needle valves? Or lack of a (or presence of a poorly operating) choking mechanism, preventing appropriate gas:air ratios so it won't combust? Or what?

I know that Kohler makes a carb heating kit (but it was not supplied as standard feature). Seems to me that if nothing else is wrong with the generator, other than it just doesn't like the cold, then a carb heater should be standard.

Many thanks for any education I can get. This has been a great forum, though I have not seen this topic discussed.
 
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Old 02-03-07, 05:04 PM
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Makes you wonder why Kohler offers a carb heating kit.. Perhaps they know about the problem.. Might want to call or e-mail them..
 
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Old 02-03-07, 10:03 PM
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I tend to think the same thing...why they offer a carb heating kit. I would guess that will fix the problem.
 
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Old 02-04-07, 07:09 AM
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Originally Posted by ChuckR600 View Post


Is it related to condensing water vapor from the natural gas, then freezing and preventing movement of throttle plates or blocking needle valves? Or lack of a (or presence of a poorly operating) choking mechanism, preventing appropriate gas:air ratios so it won't combust? Or what?

I know that Kohler makes a carb heating kit (but it was not supplied as standard feature). Seems to me that if nothing else is wrong with the generator, other than it just doesn't like the cold, then a carb heater should be standard.

Many thanks for any education I can get. This has been a great forum, though I have not seen this topic discussed.
I think you hit it on the head however what is likely freezing is the small orifice regulating your inlet pressure.
 
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Old 02-05-07, 01:49 AM
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same problem with propane

I had the same freezing up problem with an engine running on propane. The frost buildup over an hour or two was amazing. I put together a heat box to keep the regulator warm and no problems since.
 
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Old 02-07-07, 06:03 PM
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The reason the kit is an option is that not everyone who purchases these units are in cold climates. It should have been the dealer who sold and installed the gen to have highly recommended the kit. The kit is the way to go. Post back with your engines' spec number, if you would please.
 
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Old 02-07-07, 10:12 PM
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Smile

Originally Posted by puey61 View Post
The reason the kit is an option is that not everyone who purchases these units are in cold climates. It should have been the dealer who sold and installed the gen to have highly recommended the kit. The kit is the way to go. Post back with your engines' spec number, if you would please.
Thank you for everyone's input. I emailed Kohler throught their website at Kohlerpowersystems.com. I didn't get an explanation regarding exactly what is happening in the freezing temperatures (and I am still interestd in knowing) but the clear solution was to get the carb heater.

In my particular case the spec number is GM29253-GA2 and the carb. heater kit number is #GM19462-KP1. Just received it from a Kohler Generator distributer (GenPower in Wixom, MI) with detailed instructions. It draws just 37 watts and has an in-line thermnostat that activates the heater below 40 deg F and deactivates it above 60 deg F. Looks very straight forward and I plan to install it when the temps "warm" up above the current 13 degrees F.

Thank you once again, Chuck
 
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Old 02-08-07, 07:36 PM
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That's great to know!! Thanks for letting us know. Keep everyone filled in on how it works once you get installed!! Thanks, Roger
 
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Old 02-09-07, 04:18 AM
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Wixom eh? 20 minutes from here.. I wouldn't wait for the weather to warm up, I'd do it now.. After all, this cold is the reason you need it..
 
  #10  
Old 02-16-07, 06:32 PM
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It warms my heart too!

It works; it works great.

The carb heater is an approximately 5/8 in. thick D-shaped aluminum block with a heating element embedded in one end. It replaces the spacer and gaskets interposed between the carb throat and air cleaner bracket.

While installing it during a one-day 29 deg heat wave, I noticed a soft plug of ice in the crankcase breather tube that "breaths" (gases/water vapors) right into the top of the carb throat with the butterfly valve just below.

At 37 watts, it takes a while to heat up, but at steady state, when I measure the temp with a digital thermal probe tip I get 135 deg F. When probing the carb throat, I got 96 deg. Also, the rubber breather tube was replaced (95% of the length) with a copper tube that is embedded in the heater block. It is then insulated with a foam tube.

All in all, it does the job. No ice buildup to be seen. It has started within 4 seconds when it was 4 deg outside. When it was that cold, the temperature of the air just a couple inches under the air cleaner was 28 deg. Right now, it is 16 deg outside and the temp under the air cleaner is 44 deg.

The cost was $82. The reassurance when you are dependent on four sump pumps in a flood prone area next to the creek....priceless!

I hope that this helps someone else out there.

God Bless, Chuck
 
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Old 02-16-07, 10:39 PM
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Glad you got it solved, and thanks for the detailed update!
 
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Old 02-17-07, 05:19 AM
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Glad you got it done before the heatwave next week..
 
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