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Discussion Starter #1
I have a 8171 that does not get much use. I fired it up but I have to move the choke back and forth to keep it running. The last time I used it it ran for 15 minutes then it needed choke and I limped it to the garage. I love my onan and I have never had a problem with it but I also have never dealt with a onan carb. Any help is appreciated.
 

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Deere 330 Killer
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Which model Onan is in that? Might be a few things
 

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Id start with cleaning carb, new plugs, replacing fuel line and filter, sounds like a dirty carb but anyone of those things could result in it running poorly. If your on a tight budget clean carb first and see if that helps!
 

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Usually what that means is the the carb on your CCKA is at least partially clogged. More than likely the gasoline has turned bad. I like to blame the ethanol in the fuel. To really fix it I perform a multistep process.

1 - Drain some gasoline from the tank into a clear glass jar and note the color of it. Gasoline is normally clear. If it has turned slightly yellow or amber or if it has water in it, I will drain it and use it only for cleaning parts.

2 - Take the top off the carb and inspect the contents of the bowl. If a sand like substance is in the bowl or water in the bottom, then I blow out the bowl paying attention to the jet openings in the bottom.

3 - replace the fuel filter

4 - Replace the fuel line if more than 3 years old.

After the tank has been drained and blown out, put 1 gallon of gas and 2 oz of Techron in it.

Start the engine. If it still runs badly, run it at WOT and briefly place your hand completely over the air inlet of the carb. The idea is to let the engine vacuum suck the dirt through the jets. Don't close off the air long enough to cause the engine to stop running. Do this 2-3 times. If the occlusion isn't too bad this action should clear it.

Assuming the tractor now runs reasonably well, run the tractor at 1/2 throttle until that gallon is used up. Several 10 minute run sessions is better than one long one.

When that is fuel is mostly used up, fill the tank with fresh fuel and add Stabil and Techron per the directions on the labels.

It may clog again due to crud in the fuel pump, but clearing it should not be an issue. Simply take the top of the carb off and blow out the bowl and jets.
 

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Deere 330 Killer
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:ditto:

just systematically go thru the fuel system and see if that does it
 

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Discussion Starter #6
Thanks for the replies. I know how much you love Onans Richard. I had read something that you had written a while back about Onan carbs but I could not find it again. I just want to make one thing clear. You are saying to take the top off only and blow the carb out, not take the whole carb off the tractor correct?
 

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Deere 330 Killer
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Richard, are CCKA carbs the Marvel type DD carb? Or the Nikki style like the Performer series?
 

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Thanks for the replies. I know how much you love Onans Richard. I had read something that you had written a while back about Onan carbs but I could not find it again. I just want to make one thing clear. You are saying to take the top off only and blow the carb out, not take the whole carb off the tractor correct?
Yes.

It ran fine until it got a snoot full of crud so I see no reason to take the carb off.
 

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To date, I have not had to remove an Onan carb for cleaning. Same with the Briggs Vanguard. Kohler carbs are another issue. They have to be removed to replace the needle or seat. On the Kohler twins it has to come off just to clean the bowl.

The carb on the CCKA has that hateful main jet screw under the carb pointing down. It takes a special tool or some gymnastics to adjust. Once set, I leave it alone.

I missed one point on the CCKA carb. Take the idle screw out and give the hole a shot or two of 120 psi air. That procedure is like this:

Turn the idle screw in until it very lightly seats noting the number of turns. Remove screw and blow compressed air into the hole.
Replace screw and set.
When it is running and is modestly warmed up. Adjust idle speed to spec. Adjust the idle mixture for highest idle speed.

Some might say that the published # of turns is what the carbs should be set to. That is a fallacy. The published number of turns is a recommended starting point. Proper carb adjustment has to be done.
 

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Discussion Starter #11
Thanks for the help Richard. I did what you said and she runs great. I do run stabil in my machines but I never heard of techron.
 

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Techron does a nice job of cleaning fuel injectors and carbs. It just takes a while to work.
 

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Rich, is on the money. Had same problem on one of mine years ago and worked it same way and solved problem. Found out the more the machine sat, the more problems with Carb.
 
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