Great Power 38

Before you give up completely Phil, have you tried a different spark plug? I read somewhere that a plug may spark OK in the open air, but fails under pressure.

Done that Brian a while ago. Two things that have not been tested. 1. Kill switch 2. Try another ignition unit. Later today if weather holds off will bypass kill switch. Next swap the ignition unit with a DLE spare one and see if it fires up. (Note it may not perform the same as the ignition advance curve probably is not the same). I have now realised that although these GP engines are well made in Taiwan the back up of spares and knowledge is minimal except for two companies in the UK.

Definitely a fuel issue. All other items checked.

I can stick it onto my test bed and have a tinka if you like?!!

Hi Chris - As you will have read ive also looked at Phils motor so your fresh view might be a good idea. Phil is in two minds as to put the motor with Probuild or let the AerobatX look at it.

Just to review what i have done.
Leak tested crankcase (for bearing seal leak)
verified the pump works (by removing the fuel chamber cover and releasing the regulator plunger) which Phil has also carried out on his bench.
The reed block is quite a lightweight plastic structure and the reed petal mount screws had distorted the mounting point. Ive tried the flatten that distortion. The petals don't close absolutely but I dont think sufficient to prevent running.
Using a pippet ended tube, I've blown thru the idle and main jets feeds and verified the flow changes with needle adjustment.

This carb has a sprung ball valve preceding the main jet outlet which i assume opens to release a pulse neat fuel when the butterfly is opened rapidly. I know it opens because I've trickled neat fuel on the inside. when I pushed the ball with a needle point the fuel runs into the venturi. HOWEVER, IF THIS DOES NOT CLOSE IN REVERSE IT WILL ALLOW AIR TO FLOW BACK INTO THE FUEL CHAMBER AND VENT ALL THE FUEL.

C.Morris wrote:

I can stick it onto my test bed and have a tinka if you like?!!

Hi Chris. another set of eyes over it would be great. Nearly two months now since it stopped running. I will email you to arrange. Thanks. An update today 5th October. Neat fuel down carb mouth and it fires up momentarily.