VoneSII Motor
 

I have a VoneSII and am having problems with the engine running rough at high revs. I have rebuilt the motor to ensure that there are no air leaks. It has a new glow plug.

When running at higher revs the motor surges and there is a lot of small air bubbles in the fuel line.

Does any one have any suggestions for what is wrong ??

Many thanks to all.

Nic.

Check the fuel tank for leaks. Submerge the tank in a bucket of water. (sealing the pressure feed and outlet first) Try blowing into the tank through one piece of tubing and noting if there are any leaks could be a seam or the o-ring on the lid.
I had the same problem myself and a new fuel tank fixed it.