ORIGINAL: rcjetsaok
.... Upon removing the Bulb assmy and checking it out I figured out that that thing doesn't pump fuel at all !!!!! It goes from a nipple on the fuel pump inline to the carb. The fuel flows through a different line that has a inline filter and you can see the fuel. I've owned weed eaters and such with the same bulb but they always had fuel in them.It must pump air pressure somehow to ''prime the carb''... That thing don't prime crap !!!!! So with the Bulb assy on the bench, I went into the shop and cut me a piece if brass tubing and connected the 2 hoses together !!!!.. This Generator has been sitting in the trailer with no fuel in it for months. I turned the fuel selector on, set it to choke, And she fired right up on the second pull !!!....
Danno
What am I missing here?
Now that I opened up my newly purchased used generator I found that the primer bulb was missing some internal parts, (i.e. check valve) I confirmed this with the previous owner who said the bulb cover came off one day and he screwed it back on but thought something was missing.
With the internal part missing the bulb is nothing more than a straight piece of pipe, which leads me to my question '
What am I missing here with using a brass tubing and connecting the 2 hoses together"???
I did an internet search and found the following explanation on how the primer bulb works, as it turns out it is used to get fuel up to the bowl by actuating the fuel pump (The primer bulb is the vacuum source for the fuel pump)
It goes on to state that " On two stroke engines they are powered by crankcase impulse. On this generator, variations in intake manifold pressure operate the pump. Pumping on the primer bulb simulates these pressure variations and pumps fuel to the carb. Once the float bowl on the carb is full, the float needle closes, and the pump stops working."
So that explains why the two hose would need to be put together as this is the primary vacuum source for the pump,
however it doesn't explain how that fixed the priming issues????[X(] [X(]
So i am still confused...
The following is part of the article that I found at
http://www.shopfloortalk.com/forums/...ad.php?t=26555
This does NOT squirt fuel into the intake like the similar looking primer bulb on Tecumseh lawn mower carburetors. (Tillotson carbs) Instead it actuates the fuel pump and allows you to fill the carb bowl. Like the primer bulb on an outboard boat motor fuel line.
The fuel pump is needed because the carb is high mounted, and the fuel tank is not high enough to gravity feed. This is a safety feature, as a stuck car float will not drain the tank, spilling gasoline everywhere. The fuel pump can only move fuel when the engine is turning.
The fuel pump is of the diaphragm type common on two-strokes. On two stroke engines they are powered by crankcase impulse. On this generator, variations in intake manifold pressure operate the pump. Pumping on the primer bulb simulates these pressure variations and pumps fuel to the carb. Once the float bowl on the carb is full, the float needle closes, and the pump stops working.
So unless the float valve is stuck open, you can't flood the engine by overpumping on the primer. Also if the primer bulb is not working then you will have to fill the carb bowl by pulling the rope many times. I suspect this is the cause of one of the negative reviews floating on the net. Most of the other reviews praise the easy starting. If the bowl is full, and the choke and ignition switch is on, it should take no more than 5 pulls to start the engine. More than that means something is wrong and you need to stop swearing find your tools, and fix it.
To test the primer bulb:
You are going to spill a little gas, so go back and read post three if you skipped it. Turn off the gas valve. Drain the float bowl by lossening the angled screw on the bottom of the carb. Drain the line with the fuel filter
by removing the line from the fuel pump or from the filter. Replace the line, tighten the bowl drain, and turn the gas valve back on. Watch the fuel filter while you pump on the primer bulb. You should see gas filling up the line and filling the filter. Give it about 50 pumps, and check that fuel comes out the carb drain when you loosen the screw.
If the primer bulb is not working you need to fix or replace it. In the mean time you can fill the carb bowl by taking a hose, sealing it into the fuel neck with a rag, and blowing into the hose, thus pressurizing the tank. Warning. Make sure the end of the hose is above the liquid gasoline. When you release the pressure, gas fumes are going to come back up that hose. Seal the end with your tongue while drawing the next breath, and pull the hose out of the tank when you are done.