Help on carb!!!

fonzusa1 · Post by **fonzusa1** » Wed Feb 20, 2008 2:20 am

I am trying to get this sled running. Its down to the carb. This has a Mikuni VM30-138 carb. It was very clean when I tore into it. I have torn down a few carbs before and everything looks good. All holes are open!! The only way I can get the engine to run at all is with the idle screw turned all the way in. It will idle this way but if you touch the throttle it bogs out. Cannot get any rpms out of it. Air screw is out 1 1/2 turn. I checked part numbers and all needles, jets etc are correct. Any ideas?? I do see some hairline cracks in the bowl but they don't go all the way thru. Holds gas fine, don't know if this could cause a problem.. Thinking of getting a new carb. The 30mm's are hard to find. Mikuni shows the 34mm has all the same dimensions. Will the 34 be ok on this sled?? Need to know what you guys think as I'm anxiious to get this thing going. The sled has the Kawasaki 340 FA engine--only way it came. If I change carbs where will I start on jetting with the 34??

Thanks in advance!

Info on where to get carb or parts is appreciated.

JDT · Post by **JDT** » Wed Feb 20, 2008 11:44 am

What you see as cracks in the bowl may just be casting flaw lines. This is seen on most bowls.

Are you doing the idle/rev tests on the ground or with the rear elevated?

Is it hiting on both cylinders?

Mr. Deere · Post by **Mr. Deere** » Wed Feb 20, 2008 1:29 pm

I know the Manual for my sled say 1.5 turns out on the air screw but it wont run worth a dam unless I have them out 1 turn the extra half turn screws the sled up for some reason. BOB

fonzusa1 · Post by **fonzusa1** » Wed Feb 20, 2008 1:54 pm

The sled is flat on the floor of the shop. Hitiing on both cylinders. I have tried different settings on the air screw but doesn't help.

HoosierDeereMan · Post by **HoosierDeereMan** » Wed Feb 20, 2008 6:34 pm

I'm not that familiar with the Kawi engines or the fire series sleds. I have heard several mention that if the CDI is weak or bad that the engine in some cases will run but only idle. If you try to blip the throttle it will die or bog.

JDT · Post by **JDT** » Wed Feb 20, 2008 8:17 pm

Actually had this very problem a month ago on a Spit which is the same engine as you have.
Changed the CDI and it ran perfect..

For some reason, which I can not explain, the CDI had spark and it would start and idle but when the throttle was open it would not rev up.

That Girl Racing · Post by **That Girl Racing** » Wed Feb 20, 2008 10:32 pm

Sounds like the pilot jet is plugged. Peter

Danzig · Post by **Danzig** » Wed Feb 20, 2008 10:58 pm

I agree with you Peter, plugged or the wrong pilot is being used and it is too small.

fonzusa1 · Post by **fonzusa1** » Thu Feb 21, 2008 3:44 am

I found a NOS coil/cdi for it which I replaced. Had spark with old one but not sure if spark was hot enough. The pilot is a 30 which is correct. I have cleaned carb and jets twice but same result. I have adjusted air screw from 1 turn to 2 but doesn't seem to matter. I can get it started with the idle screw all the way in and thats it. Am going to change out the jets anyway with a new needle/seat. See if this helps. I did a google search and found where someone was having the same exact problem with a Kawasaki engine and was told to change out the needle and seat as it was flooding out engine off idle. Will let you know how it tuns out. Any other ideas??

Thanks

fonzusa1 · Post by **fonzusa1** » Fri Feb 22, 2008 5:17 am

Replace needle and seat and no change. Swapped out carb with another sled and still no change!! Now what??????????

Thanks

larky · Post by **larky** » Fri Feb 22, 2008 7:49 am

not familiar with your sled, but if it was my sled I would be looking at the fuel pump. fuel pick-up in the tank and any hoses associated.

Liquifire 4/6 · Post by **Liquifire 4/6** » Fri Feb 22, 2008 11:05 am

Have you tried disconnecting the speed limiter?

JDT · Post by **JDT** » Fri Feb 22, 2008 11:12 am

The exhaust/muffler my be plugged.

Disconnect it and restart to see if any change is noted.

fonzusa1 · Post by **fonzusa1** » Sat Feb 23, 2008 12:42 pm

Exhaust is not plugged. Fuel pump good with new lines and new line in tank. Its getting gas. Tell me more about the speed limiter. Are you talking about the rev limiter? Where is this located. I didn't know this engine had one?? Didn't mention before but the maiin and pilot jets are new. Thanks for all the ideas. Any more? Info on rev limiter? I would like to see this thing run!!

Thanks

JDT · Post by **JDT** » Sat Feb 23, 2008 1:05 pm

I do not have a Snow Fire so I can not tell you where it is located. It is a small componet box that has 2-3 connectors on it.

What it is suppose to do is kill the ignition system if the RPM's rise above a preset level to prevent over revving the engine.

If it fails one of four things will happen.

1) Engine will run fine but will rev up higher then max spec

2) Engine will not start due to no spark

3) Engine will start and idle but will not rev up beyound a certain point that is less than WOT.

4) Engine runs and accellerates fine but cuts out intermitantly at midrange RPM.

To bypass or test it just pull the connector that has the two white wires on it.
This will remove the ability of the limiter to effect the ignition system operation.