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Author Topic: Gasoline/carburetor gumming  (Read 2297 times)
Iceni John
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« on: November 29, 2012, 12:32:14 PM »

For those of you with gasoline-fueled generators:

I have a 3500W Champion portable generator that is only for emergency use  -  I presently run it every two or three months for maybe one hour total a year, just to keep it in working condition.   I put lots of Stabil into the fuel, and always keep the tank completely topped up.   It always starts on the first pull, and it runs smoothly and without any exhaust smoke even under full load.

What do you do to prevent carburetors from gumming and eventually needing to be cleaned out?   I heard that one could turn off the gasoline's petcock into the carb and starve the engine of fuel as it was running, and this would leave the carb empty and prevent gumming problems.   I tried that yesterday, but it was misfiring and spluttering so much I didn't dare leave it running that way until it ran out of fuel, so I turned the fuel back on.   Is this technique advisable, or could it cause more problems than it cures?

In the long-term I want to convert it to LPG which will avoid this whole potential issue, but for now does anyone here have any ideas for reducing the chances of a gummed-up carb?

Thanks, John
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1990 Crown 2R-40N-552:  6V92TAC, DDEC II, HT740, Jake.      Hecho en Chino.     
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Utahclaimjumper
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« Reply #1 on: November 29, 2012, 01:05:02 PM »

 Sta-bil is the right solution (pun intended) and will protect your system for a full year or more, be sure to run the engine long enough to pull the treated fuel into the carb.>>>Dan
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Utahclaimjumper 
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« Reply #2 on: November 29, 2012, 01:19:59 PM »

With the corn crap they are putting in gasoline to day sta-bil will only last 3-4 mths    dave
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1990 mci 102c  6v92 ta ht740  kit,living room slide . home base huntsville ontario canada
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« Reply #3 on: November 29, 2012, 03:42:26 PM »

The red bottle Sta-bil is mostly alcohol use the marine grade but a premium grade gasoline work good also me I drain the carburetor then run paint thinner through the line and bowl area works for me here in AZ turn the gas on starts every time
« Last Edit: November 29, 2012, 04:20:02 PM by luvrbus » Logged

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Iceni John
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« Reply #4 on: November 29, 2012, 04:15:06 PM »

Thanks, good advice (as always).   I'll do that.

John
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1990 Crown 2R-40N-552:  6V92TAC, DDEC II, HT740, Jake.      Hecho en Chino.     
Behind the Orange Curtain, SoCal.
Hobie
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« Reply #5 on: November 29, 2012, 04:17:05 PM »

So what is the hot tip when the gas goes bad without Stabil and gums up the carb?   Ditto to the ethanol, wrecks the carb gaskets and puts a yellow dusty film inside the bowl.   Can't buy non-ethanol gas here in Calif.  ( don't want to go to airport Smiley  
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Gerry H
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« Reply #6 on: November 29, 2012, 05:02:19 PM »

   I asked that question to a guy that fixes lawn mowers weed wackers small engines etc and he said it's a lose lose situation and there is no best way. He said using gas and stabil will eventually lead to gum/build ups and that draining/running it dry, will dry out the gaskets causing vacuum and liquid leaks. He said gas and stabil was his preference, keep the gaskets wet. YMMV Good Luck!    Gerry H
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« Reply #7 on: November 29, 2012, 06:11:38 PM »

Not happy with Sta-bil.  I have had to take apart 4 carbs this year.  What I do on my generator, which is the same as yours is shut the petcock and run it out of gas.  I've never had gas do this to me over a winter until I used Sta-bil.  No more for me.
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Ed Hackenbruch
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« Reply #8 on: November 29, 2012, 06:29:20 PM »

I have been using Sta-bil for 9 years in my truck and car that i leave in storage in Yuma when we leave for the summer. Usually gone for about 6 months, so far have never had a problem firing them up.  I put in 2-3 times as much as they say you need to use, i figure with the summer temps being so high and with the chance that i might be gone longer than i think, that using more might be a good idea.
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« Reply #9 on: November 29, 2012, 06:49:52 PM »

Started in the working world as a mechanic in a small engine shop, later I thankfully got into the Onan emeragency generator world, been in it for 40+ years, so I have became very opiniated on this very subject.
Have found the very best results are from using a good brand name high test gasoline, I only use it in my small gas engines, and never have an issue. That includes the chain saw, that I mix a 1 gal can of 2 cycle mix that lasts about 2 years, used mostly for cutting up pallets for dumpster.
Also the 18 hp engine on lawn mower, it sits all winter, nothing special, maybe 5 months with zero issues. Everything else is diesel  Grin
I do not like additives, and from flying, the 100LL gas in airplanes lasts a very long time sitting in an airplane, again it is a high octane and has a very long shelf life, the auto hi test is less octane but still a much higher life than cheapest gas.
As said, I am very opiniated. I do what works for me. Grin
FWIW
Dave
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« Reply #10 on: November 29, 2012, 07:09:39 PM »

  (snip)  I do not like additives, and from flying, the 100LL gas in airplanes lasts a very long time sitting in an airplane, again it is a high octane and has a very long shelf life,

     Yes, and there's no ethanol in it (ethanol doesn't have high enough "vapor pressure" - it would boil in the fuel lines at altitude).  @ $5.00+/ gallon it's expensive but it is much more stable in a carburettor than autogas.  Also, going to the airport to buy it is a PITA, thank goodness my local airport has credit card-serve yourself pumps and it's small enough tht I can drive up to within 25 feet of the pumps.
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« Reply #11 on: November 29, 2012, 07:11:05 PM »

There are two gas stations near me that sell non-oxygenated gas for small engines and the like.  That is all I use in my small engines these days.  I've heard it recommended that you put Sta-Bil in your gas as soon as you buy the gas before it starts degrading.

I run my engines dry for the winter, but I had a heck of a time getting my pressure washer started this fall after sitting a year.
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
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« Reply #12 on: November 29, 2012, 08:26:25 PM »

My way, on the recommendation of a good friend who is into small engines.

I put the appropriate measure of Stabil into the gas cans before the trip to the gas station.

All the gas that goes through the small engines is treated all year.

22 HP commercial mower that does close to 30 hours a year, a leaf blower that sits around, a chain saw is used in bursts, with long periods in between, 3K generator that sits around.

Also, we dose the various family hobby cars according to the measure, which I host in the garage for the winter.

The gumming troubles, which show up as poor starting, are much less frequent than when I didn't.

For instance, the leaf blower starts on the 2nd or 3rd pull anytime of the year for the last 4 years, since the last servicing. There are certain snow conditions for which it is more useful than the snow shovel.

Real, or imagined, I will continue.

happy coaching!
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« Reply #13 on: November 30, 2012, 07:44:54 AM »

For those that will use 100LL aviation fuel bear in mind that it has a really high lead content as compared to auto fuel of bygone years.  Also 100 octane fuel because it burns slower than normal auto fuel can play hell with high rpm 2 cycle engines.  If u use this fuel as I do in some of My street rods just remember lead and cats do not mix very well!  Just My take for what its worth.  John L
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« Reply #14 on: November 30, 2012, 08:23:46 AM »

Mysterious how all my cats have fallen off. Huh
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« Reply #15 on: November 30, 2012, 09:19:57 AM »

Convert it to propane.  Problem solved, simple, cheap, most of all RELIABLE\I
It'll sit for years and start on the first cranking
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Iceni John
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« Reply #16 on: November 30, 2012, 12:38:26 PM »

Convert it to propane.  Problem solved, simple, cheap, most of all RELIABLE\I
It'll sit for years and start on the first cranking
I plan on doing that.   Champion's website no longer lists any LPG generators  -  they used to have a few LPG models.   Do I need to replace the entire carburetor, or can I adapt my present carb?   Are there kits available to do this?   FYI, it's a 196cc Honda-clone engine.   Fortunately I have a spare outlet on my LPG manifold that can feed it.   If it's not a major job I'll convert it soon.

Thanks, John
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1990 Crown 2R-40N-552:  6V92TAC, DDEC II, HT740, Jake.      Hecho en Chino.     
Behind the Orange Curtain, SoCal.
wg4t50
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« Reply #17 on: November 30, 2012, 02:25:27 PM »

Yes, LP or Nat Gas is perfered for simple and easy operation.  Depends on the engine, some are very simple to adapt to the vapor fuel, some take a new mixer/carb setup.
Only down side to the LP fuel, is the cost, sure is nice, just expensive fuel, why I built a 12 kw diesel, burns 1/3 the gal of the LP dling the exact same load.
Do what makes you happy
Dave
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« Reply #18 on: November 30, 2012, 03:32:58 PM »

Aside from being more costly, you'll lose 25% power too.
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Iceni John
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« Reply #19 on: November 30, 2012, 04:25:34 PM »

I'm not worried about the cost  -  my generator is only for very occasional emergency use, not my primary source of electricity.   If I lose some output power, again it won't matter much.   I just want to be sure that if/when I actually need it to run, it does.

Thanks, John
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1990 Crown 2R-40N-552:  6V92TAC, DDEC II, HT740, Jake.      Hecho en Chino.     
Behind the Orange Curtain, SoCal.
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« Reply #20 on: December 02, 2012, 10:13:57 PM »

I like "Sea-Foam" gas treatment. Like others mentioned above, just put the prescribed amount (I just approximate it, using about four ounces per five gallons of gas) before I fill the can. It's automatically well mixed when I fill the can. Then I pour from the five gallon can to smaller containers for mixing 2 cycle oil. I don't run them dry, just leave the gas in them until I use them next, sometimes three or four months at a time. I have about 14 different gas powered gadgets around here and the SeaFoam works well for me. The best price I've found is at Northern Tool. No carb problems in about seven years now. (Knock on wood)
So Far, So Good...
Dennis   
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« Reply #21 on: December 03, 2012, 09:47:07 AM »

I use these guys.  You can do it 2 or 3 different ways.  I simply buy the garretson model KN regulator (it's highly recommended- others don't perform as well), take the carb off and drill a 1/4 inch hole up through the middle of the main jet into the venturi, solder a 1/2" brass hose barb to a piece of 1/4" brass tubing and cram it up into the hole just drilled so that it sticks about halfway into the venturi.  Then use a 1/2" ID hose to hook the hose-barb to the regulator's output, with a 1/4" gate valve in the middle.  The gate valve serves as a richness adjustment- it's somewhat tricky to adjust the first time but once you've got it running it's simple to tune and it's good forever without readjusting.
This method costs about a hundred bucks (mostly for the KN regulator) and takes me about half an hour.  You can occasionally find KN's much cheaper on ebay

If you want to do it simpler and less permanent, use a kit from these guys.

http://www.propanecarbs.com/tri_fuel_kits.html
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1962 Crown
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« Reply #22 on: December 03, 2012, 10:21:17 AM »

Is the fuel tank coated?  Maybe you have a incompatability (sp) with the type of fuel you are using.  The tank coating and rubber fuel lines (if any) are literally melting and clogging the carb?  FWIW, we always ran the gas out of the carb, be it airplanes, bikes, boats, tractors. etc.., particularily (another sp) if stored any time.  I can't speeeel today.  HB of CJ (old coot who needs his coffed) Smiley Smiley Smiley
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« Reply #23 on: December 03, 2012, 01:11:09 PM »

I've heard that the ethanol in E10 gasoline will dissolve certain types of fuel lines.  That probably explains why I had a fuel leak on my Stihl weed whip.
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Brian Elfert - 1995 Dina Viaggio 1000 Series 60/B500 - 75% done but usable - Minneapolis, MN
Iceni John
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« Reply #24 on: December 03, 2012, 07:32:22 PM »

If you want to do it simpler and less permanent, use a kit from these guys.
http://www.propanecarbs.com/tri_fuel_kits.html


Their website is helpful.   Maybe that's how I'll do it, with the conversion kit they sell for Champion's carbs.

Thanks, John
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1990 Crown 2R-40N-552:  6V92TAC, DDEC II, HT740, Jake.      Hecho en Chino.     
Behind the Orange Curtain, SoCal.
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