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2 Cycle Engine Problem


Chad H's Avatar
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06-25-02, 11:20 AM   #1  
Chad H
2 Stroke 250 cc

When I kick start the engine on my dirt bike initialy it will fire and then dies straight away.After 4-5 atempts it doesn't fire at all.
Thinking it may be fuel starved I checked the fuel line -it was clear. Next I stripped the carb, fuel chamber was full and I found nothing blocked, everything was clean.
I will take a look at the spark plug next,to confirm that it is clean etc, the fuel is a good new mix that I have already used.
Has anybody encountered this before? are these syptoms familiar? Why did it run OK last time I used it? any recommendations ?

 
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cheese's Avatar
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06-25-02, 10:37 PM   #2  
Hello Chad!

Check to be sure the choke is not sticking shut. Make sure your spark plug is not wet, and check to see if you have a steady flow of fuel to the carb. This sounds to me like a restriction in the carb, but some more checking needs to be done.


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06-26-02, 01:40 PM   #3  
Chad H
The spark plug was wet with fuel when I removed it.
Black and sooty condition.
There was a spark when I tested

 
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06-27-02, 12:25 AM   #4  
Then you have a fuel problem. It is getting too much gas for some reason. Things that would cause this are: The choke is not opening, the air filter or intake is restricted, the float is bad or misadjusted, the needle and seat are leaking, or the air-fuel ratio screw is backed out too far.

I would reccomend removing the carb, clean it out, replace the float, needle, and seat, and put it back together. Make final adjustments. This should take care of your problem. Before doing this, check to be sure your choke is operating properly (opening and closing) If it is staying closed, or partially closed, this is your problem.


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07-08-02, 11:38 AM   #5  
Sounds like a compression problem to me.....warn or damaged rings

 
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07-08-02, 10:16 PM   #6  
2 reasons I think it is carb related are #1: the plug is wet and sooty. This indicates incomplete burning of the fuel in the combustion chamber...mainly caused by too much fuel metered into the engine. #2: Chad stated that it ran fine last time he used it. Rings don't wear when they're not being used. They can stick though. More commonly though...gas left in a carb when the engine is not in use for some time will gum up and cause carb trouble. Especially if condensation buildup has occurred. Then the float can develop a leak, etc...and problems are compounded.


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07-09-02, 10:07 AM   #7  
Originally posted by cheese
2 reasons I think it is carb related are #1: the plug is wet and sooty. This indicates incomplete burning of the fuel in the combustion chamber...mainly caused by too much fuel metered into the engine. #2: Chad stated that it ran fine last time he used it. Rings don't wear when they're not being used. They can stick though. More commonly though...gas left in a carb when the engine is not in use for some time will gum up and cause carb trouble. Especially if condensation buildup has occurred. Then the float can develop a leak, etc...and problems are compounded.

Good call.......re-reading it I agree.....usually the plugs look the same with bad rings though.....wet and black. I have alot of neighbor kids bring their dirtbikes over for me to fix and they tell me the same thing.....'It ran fine last time'. I usually find out later that they ran it out of gas(death to dirtbikes)/ over-revved the heck out of it/ or the aircleaner fell off.

 
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07-09-02, 09:14 PM   #8  
Yep, if he hadn't stated that it ran well last time used, then rings would be a suspect to me. More detail would be required to make a better diagnosis, but he hasn't posted anything further. If we find out that he did run it out of gas, or run lean, etc.. then I will lean your way on the rings.

I am wrong more often than I would like to admit, though. You may be right. That is why I like these forums, where one question can get many answers from different people with different opinions and experiences. Your input is welcome and appreciated!


"Who is John Galt?" - Ayn Rand (Atlas Shrugged)

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07-10-02, 01:30 PM   #9  
This site looks like it is set up pretty well. i tripped over it looking for tips on outboard waterpump replacement. I know the basics of it but just looking for pointers.


nice site though.....ill keep poking my nose in. I moderate 2 other sites also and that keeps me going.

 
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