!Newbie! irvine .40cc starts but wont stay going??

Hi John, The engine isn't drawing fuel properly. Did you get this engine new, or second hand? Do you have a manual for it? If you do, reset the needles to where the manual says as a starting point, before you try anything else. If you don't have a manual, maybe someone here can give you the needle settings?

Once you've got the needles where they should be, make sure your tank is plumbed correctly and your muffler pressure fitting isn't blocked. Also make sure your clunk line isn't sucking onto the back of the tank.

Are you priming the engine before you try to start it? Does the fuel 'suck' up to the carb within a couple of prop flips if you put your finger over the carb opening?

Where is the fuel tank in relation to the carb (how high)? The tank centre should be approx in line with the carb with the plane level.

How far have you got the throttle open when you're trying to start the engine?

Honestly, it just sounds like you've got the main needle too far in. By blowing in the vent line, you're providing *way* more pressure than your muffler would ordinarily be. If it runs ok with this amount of tank pressure until you stop blowing in the vent line, it's *definitely* not going to draw fuel up to the carb by itself. Open the main needle at least a turn and see what happens.

This all assumes you've got a working engine of course, with no obstructions in the needle valve/carb etc.

MrBonk

A week ago, when you were "John Smith" , you posted a virtually identical question and got a couple of responses. Why did you not try the suggestions made then, and post back the results, rather than ask the same question all over again?