Fuel Filters for Pioneers

General Messages Post you pics as well

Postby JPXman » Sun Jul 05, 2009 12:28 am

yes thats it exactly. after you warm them up and run them up (full power on the ground for 5 minutes on a ship you're not totally familiar with) there should be no bubbles in the lines at any power setting.

i've also found that shaking/vibrating fuel lines that aren't properly secured or routed can cause fuel vapour bubbles which can lock a fuel pump or starve a carb just as easily as air bubbles.

The JPX setup i use, uses a mikuni fuel pump that uses the pulses from the crankcase for pumping. I used to prime my engine by disconnecting the outlet of that pump and inject gas into the carb float bowl with a syringe through the line i disconnected, then using a piece of fuel line about 6" long, stick it on the pump and suck the gas up from the tank through the pump with my mouth. then i'd reconnect the original line to the carb. the pump holds the fuel up the line quite well, and with the float bowl primed, the engine will start and suck the gas up between the pump and the carb. after tasting gas for weeks i looked for a better way.

I tried chappy's method of blowing in the gas tank vent to push fuel out the fuel line, but i found my tank required so much air i had to use a bicycle pump. after using that for a while with great success, i noticed that the pressurized fuel tank expanded quite a bit, and might be causing it stress on the plastic welds of the tank so i stopped doing it that way.

So to tell you the truth i am still searching for the perfect 2-stroke priming method. my friend Daffy here in edmonton uses the little 12V/24V fuel pump from Facet, mounted just above his tank. flip on the switch and it pumps gas perfectly and no bubbles with the engines running. I don't have a battery on my plane yet, but it might be a solution if you wanted to carry around a car battery during startup.

all you have to do is get that float bowl full - there'll be enough gas in there that once the engines are running, throttling them up will pull the gas up from the tank before the bowl runs dry.

keep at it, you'll figure it out. sounds like you're being safe and methodical which are virtues in lazair flying.

Tyler
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