I have been running my 140dz for a year or so now, with no problems whatsoever. Last weekend i flew without incident, but i went to start my engine today I had no joy. Nothing has been changed on the engine or plumbing, but the engine seems to be pressurising the tank, as i turn it over large amounts of bubbles come from the clunk and no fuel is sucked into the engine. Does anyone have any ideas?? Many thanks

Please head over to engine support forum, YS section. Dave Shadel can help you.

First of all, the DZ engines do not pressurize the fuel tank. Unlike other YS engines, they use a fuel pump, rather than a pressurized and regulated fuel system.

It sounds like the pump diaphragm has a tear or hole in it. Check with Probuild for the necessary repair parts.