[force_of_iron]

my engine is a TB340A-C202 its a kawasaki engine at 339cc and its 2cycle. this thing was made around 1986 or so and its free air cooled

my problem is that when i start it up its idle wont stay steady. it sort of just does what ever it wants! i boght a 32mm mikuni which helped out some. someone told me that the carb is to blame but its brand new. would it be fuel and air mixture thats doing it? and it throws out alot of white exhost like crazy. and the plugs get wet which makes my engine die after a few minutes. what whould i do with the carb to make it run right?

 

[puree]

how old is the fuel you are running,,,, was it stabilized??? bad fuel will kill ya,,,
if your plugs are getting really wet, are the they right plugs,,,, what kind of oil mixture are you running???
was the new carb set up for this sled, or was it put on stock,,,,

 

[Spaceman]

I would pressure test the engine. its age and erratic idle may indicate bad crank seals which will have your idle all over the place.

 

[Firebirdss]

I hope the crank seal isn't the problem. Those engines were known for bad crank seals, I had one a couple of years ago. A compression test won't tell if you have a bad seal though. The seals cost me $5.00 but the labor was around $300.00.

 

[Bauer]

Correct me if i am wrong, but, on my old sled, white plugs = pistons shot.

Bauer

 

[puree]

white plugs means you are running too hot,,,, doesnt mean the piston is shot yet,,,

force of iron, if you want to test your crankcase bearings,,, spray some wd40 behind your drive clutch on the drive shaft as the motor is running,,, it isnt easy as the clutch spinning is gonna wanna throw the wd40 everywhere else,,,, when you do get some down there, if it idles up,,,, your crank case bearing is bad. if it is bad, pull the motor and change both ends,,,, the other one is behind the stator and I dont know of a way to test that without pulling it out.

by chance, where do you live??

 

[Spaceman]

Originally posted by Firebirdss@Jun 7 2004, 07:52 AM
A compression test won't tell if you have a bad seal though.

I said pressure test, not compression test.

 

[abc]

The carb is no jetted right and maybe he also have a clogged exhaust. May also be the seals as other told too.

 

[94ZR580]

I always though that a wandering, or hunting idle is the result of a lean condition? Although, fouling plugs are usually the result of a rich condition. Like was said previously, look for an air leak; crank seals, cylinder base and head gaskets, carb flange, etc. A pressure test will tell you where most of those leaks are. Make sure you are using fresh gasoline and the oil mixture is correct. The other comment about the correct spark plug is referring to having a plug that is of the right heat range. A plug that is too cool will foul out, and plugs that are too hot will lead to detonation. Make sure you have the correct plug for the motor.

 

[Firebirdss]

sorry spaceman, I guess I was reading faster than I can comprehend.

 

[Spaceman]

That's totally O.K. No harm done.

 

[hoxdesigns]

I have a TB340A-C202 and each cylinder's plug is gold colored (good mixture/ temp). The problem is both cylinders won't run the same time because the CDI/ ignition coil is firing both plugs the same time at ONCE per revolution. If both plugs are hooked up, the default is the forward one will fire and the rear one won't. Top RPM is the same, 4,700 RPM, if the rear plug is hooked up or not. If I run the rear cylinder, max RPM is 3,900. Why is the ignition coil only firing ONCE per revolution? I took video of the plugs external to the engine, slowed the video to count sparks per revolution. The plug that's not firing, of course, is covered with fuel/oil. So I'm only burning half the fuel and have about one third power, as only one plug is firing, the crank is having to take the other piston for a ride. If I remove the either spark plug physically, max RPM is 2,500.

 

[KGtoy]

Have you check that spark plug cap for 5k ohms? Assume you're using good plugs, and not fouled ones.

 

[hoxdesigns]

Have you check that spark plug cap for 5k ohms? Assume you're using good plugs, and not fouled ones.

Yes. 5k ohms, gapped optimal and burn color is gold. I was swapping the plugs around with each start.