Having trouble with my skywriter
 

As the title says, I'm having trouble with my Sullivan Skywriter. It works perfectly on the ground, with the engine off. When I crank the engine, it does not work. It will pump for about 2-3 seconds every once and a while. I'm running a 100cc twin, the smoke pump is set up with a 9.6 volt battery, and a heavy duty switch. I have check my plumbing and connections. All are good. I can pump a full tank out on the ground without the engine running, but as soon as I start the engine it stops working. Anyone else had a problem like this? Any help would be great.
Thanks, Canardman

RE: Having trouble with my skywriter
 

I'd be interested in finding out how the line is plumbed to the muffler. Since it won't work with the engine running it could be effected by back pressure from the muffler. That's providing it's plumbed to a muffler and not to a nipple on the engine case...

RE: Having trouble with my skywriter
 

It is plumbed into the mufflers via a check valve. Have checked the valve and it IS in the correct way. Between the pump and mufflers. The problem is not delivery, the pump won't run at all when the engine is running.

RE: Having trouble with my skywriter
 

Send it in. You may have a weak pump.

RE: Having trouble with my skywriter
 

I thought that may be the problem. I went to my LHS and got a new one.... Same problem.