hillcares

I just installed my dle 20cc to supercub,i have noticed the fuel wont go to the carb even if I cleaned already the carb membrane,flip the prop.I already break in this engine in my bench for 1/2 gallon.What did I miss?thanks

Lifer

My Feedback: (1)

Check the vent/overflow line. It should breathe freely. Also, sometimes you need to direct prime the engine until it starts and gets fuel to the pump membrane.

a1pcfixer

My Feedback: (7)

Since you claim to have already bench run the eng, I'd be looking at your fuel lines.

Carb fuel line connected to clunk line from tank (NOT the vent line?)

Vent line not being restricted by being crimped somewhere?

No air leaks?

All connections in fuel line have zip-ties (to prevent air leaks & keep clunk on)?

Antique

My Feedback: (4)

Be sure the membrane with the metal center is on top of the gasket on that side.
The other membrane goes against the carb under the gasket

Jezmo

Check the diaphragm/gasket assembly order like Ralph says and if they are correct then look at all of your plumbing as Jim suggests. I usually plug my fuel pump hose into the hose going to the carb and pump fuel in and out of the tank - I'm looking for leaks while pumping fuel in and bubbles in the hose while pumping fuel back out. If you are getting bubbles in the line then you have a leaking connection that must be fixed. The volume is too small on the carb pump to overcome any air leaks in the plumbing. If it ran fine on the bench and now has fuel draw issues then something isn't right in the plane's fuel system.

hillcares

Thanks for the help guys!

a1pcfixer

My Feedback: (7)

Did ya get it fixed?
Which was the problem?

hillcares

yes I solved the problem.its the diaphragm that I installed incorrectly.Now its pumping ok.thanks

Octopus RC

My Feedback: (2)

Did you check the reeds inside of your valve block ?

MetallicaJunkie

ive put a membrane backwards one time( a long time ago)... the petals were of and the engine would only cough and pop...i was stumped and the local lawnmower shop "fixed" it for me