Carb Adjustment

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  #1  
Old 08-15-10, 02:43 AM
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Carb Adjustment

I have a John Deere 185 lawn tractor with a FC540V Kawasaki motor. What is the setting for the mixture on this? I found it once "somewhere" on the web but now I can't find it. I think you screw the adjustment screw in until it just seats and then back it out 1 1/2 turns. Does that sound right?
I've got a mower that's driving me nuts.
I can start out cold and mow for about a half an hour and then the motor starts to sputter and it sounds like it is missin out. I can disengage the blades and lower the throttle and it will smooth itself out after about a minute. I can then slowly increase the throttle to full throttle and engage the blades and I'll be able to mow for about another 2 minutes and then it starts all over again. When the engine is sputtering and missing out it smells like it is running rich so I thought I would try to adjust the carb. I took it off and had it cleaned a couple of weeks ago and put it back on but I think I need to adjust the carb.
Any help out there? Thanks
 
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Old 08-15-10, 04:09 AM
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The 1 1/2 out from lightly seated is used as a starting point, Indy. Then small adjustments to fine tune from that point. As far the adjustment, you shouldn't have to go far. A lot of times the 1 1/2 takes care of it.

How does the spark look with the new igniter? With good fuel delivery to the carb, it really sounds like ignition, if you're getting some good run time out of it.
 
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Old 08-15-10, 06:34 AM
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Originally Posted by marbobj View Post
How does the spark look with the new igniter? With good fuel delivery to the carb, it really sounds like ignition, if you're getting some good run time out of it.
I didn't check the spark after this round of problems. I assumed it was OK because when it starts acting up, I can turn it off and it will start right back up, but at low throttle.
Do you still think I have a spark problem?

Could it be the coil? Any way to test those? If I check for spark when I start having problems, what should I be looking for?

I'll try adjusting the carb and see if that helps.

Thanks for the help
 
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Old 08-15-10, 08:56 AM
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I'd do the carb first. If you have an adjustment issue you'll normally see a problem right after it's warmed up to operating temperature. When you get a half hour out it with no problems, though it is usually something else. It can be things in the fuel delivery to the carb and those have to be eliminated.

A coil can be on its way out and act like what you're describing. A weak spark gives you a partially burned fuel = acting like an overly rich condition. The kicker is the electrical is fine when cold, but starts failing when it heats up with use. For that reason I would say your coil suspect, since you have the new igniter.

Checking them conclusively is something most do with a "known good" replacement. If you check the spark and the coil is at fault, it's probably a faint yellow instead of a bright blue.
 
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Old 08-15-10, 03:19 PM
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I adjusted the carb. It was set at 2 1/2 turns out so I set it at 1 1/2 turns. I put the inline spark tester on before I started and it started right up with a nice bright spark. It only ran for about 5 minutes and it died. I was messing with the carb and I didn't have a chance to lower the throttle before it died. It wouln't start again and the spark was very faint/weak. I guess I'll pick up a coil and go from there.
 
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