Fuel Pumps failed to prime on 03 Rx-1

[01srx+03rx1]

Anybody else had difficulty getting the fuel pumps to prime after sitting for a while. Basically I drained the gas in spring, emptied the floats, etc. Not long ago, I went to start it up so I put 2 gals of gas in it and began cranking and cranking. I suspected no fuel to the carbs so I pulled the outlets off and cranked and cranked, no fuel was being pumped out. Next I removed the inlets, I sucked on each and was rewarded with a mouth full of gas. Any ideas or similar experience?

 

[vmaxjohn]

First I've heard of it. Sounds like you should put a fresh gallon of gas in the tank before she goes into storage. You can use a rag and an air hose in the filler neck to pressurize the fuel system, works for carbed cars!

 

[rxrider]

Take a plastic bottle of some kind that will fit into the filler neck. Cut a little hole on the bottles edge near bottom of bottle. Put bottle into filler neck and blow to pressurize the fuel tank. When pressurized, crank the engine. This trick will help fuel getting into the fuelpump. If there are no gas in the fuel lines and in the pump, the pump will not do much work. (Be careful not to inhale from the bottle, breathe though your nose)

 

[LazyBastard]

Fuel pump will never suck fuel up that high. If you want it to prime itself, you'll need a full tank. If not a full tank, get the fuel tank VENT line, take one deep breath, full choke, exhale full breath into fuel tank, hold, crank engine until it starts.

 

[01srx+03rx1]

Lazy, That was my analysis of what was going on. However, I didn't think this possible from a design standpoint, i.e. fuel not gravity feed to the pumps at low tank levels AND a pump arrangement that doesn't have enough authority to prime itself at low tank levels? This could be a bit embarassing out on the trail, for instance, say you are out and run out of gas. You borrow a gallon or two from a farmer to get you to the nearest station. How do you get the darn thing going again? BTW - I tried the pressurized tank method, I didn't try the vent hose. Ultimately, I got it started by pulling the pressure side hoses off and, using a small funnel, filled the float bowls full of fuel. This got the engine started and utimately got the pumps primed.

We do have a battery in this machine, anyone know of an electric fuel pump that would work in this application?

 

[Mikey]

Wouldnt a primer bulb from a Rotax work better you copuld prolly plumb it into the float bowls easy enuff.

Or better yet wouldnt lowering the mounting points of the fuel pumps make more sense?

Ill bet some wind tunnel engineer from Yami wanted them to be cooled by incoming air and thats why they are mounted up high.

My Question to everyone is how do you start the #$&^ with a dead battery im sure you couldnt spin it over by hand but i really hope im wrong.

 

[BlueRx]

Dead Battery

Somebody had posted before that they had started it with a pull rope on the clutch. Don't remember who and I have not tried it.

 

[LazyBastard]

Lazy, That was my analysis of what was going on. However, I didn't think this possible from a design standpoint, i.e. fuel not gravity feed to the pumps at low tank levels AND a pump arrangement that doesn't have enough authority to prime itself at low tank levels? This could be a bit embarassing out on the trail, for instance, say you are out and run out of gas. You borrow a gallon or two from a farmer to get you to the nearest station. How do you get the darn thing going again? BTW - I tried the pressurized tank method, I didn't try the vent hose. Ultimately, I got it started by pulling the pressure side hoses off and, using a small funnel, filled the float bowls full of fuel. This got the engine started and utimately got the pumps primed.

We do have a battery in this machine, anyone know of an electric fuel pump that would work in this application?

There won't be an issue of starting on the trails, since the fuel pump won't be bone dry. When the fuel pump is dry, the diaphram won't seal, and thus less vacuum is on the line. By pressurizing or completely filling the tank, you set it to not require (as much) vacuum.

 

[LazyBastard]

Mounting the pump lower won't help since the struggle is to get the fuel UP to the top of the tank. Don't worry about on the trail since the diaphram will still be wet and seal well.

 

[kmer]

Mounting the pump lower won't help since the struggle is to get the fuel UP to the top of the tank. Don't worry about on the trail since the diaphram will still be wet and seal well.

Makes sense to me. Mine dried out over the summer as well. I just splashed some juice down the cylinders and presto - vroom vroom. Damn I love that sound.