AN4022-1

[prkaye]

I'm a bit suprised that nobody has responded to my question about the fuel primer discharge nipples. I searched the forums for AN4022-1 and found nothing. Has everybody gone with Vans' stock parts here for priming? I find that hard to believe - this forum seems to be full of folks who find ways to improve on things.

Here is the idea again, in a bit more detail...

The 816-2 fittings that are supplied with the priming kit are used as the nozzles that go into the engine. These are wide open on the side that screws into the engine. I have thought of using AN4022-1 which appear to have a much smaller orafice that looks like it would better atomize the fuel going into the cylinder. Another advantage would be that the smaller orifice would make it harder for unwanted debris to get into the cylinders through the priming system. The downside is these require soldering AN800 fittings onto the copper tube to make them work. Another downside is that the smaller orifice could get blocked easier.

Things I'm left wondering...

1) would the AN4022-1 actually provide better fuel atomization than the 816, and is this important for priming?

2) would the pressure provided by the automotive fuel pump be sufficient to push the fuel through the smaller orifice of the AN4022-1?

3) How would you even know if your primer nozzles became blocked? Would there be any indication other than hard starting in cold weather?

If anybody here has considered alternative priming nozzles, and has thought about these questions, please let me know.

[Norman CYYJ]

The fuel coming out of the primer actually goes into the intake area. When the intake valve opens then the fuel gets sucked into the cylinder. It doesn't make much difference whether you use the wide open fittings or small openings. If using the open fitting you don't have to prime as long. For pieces of junk coming thru the line don't worry about it. If they are that big then the screen in you gasculator has large holes in it or is missing. It won't harm the engine.

[rocketbob]

Its been at least five years since I've used the primer system in my RV-6. If I were building another one I wouldn't bother with a primer system. Two pumps of the throttle AFTER two blades, it fires up every time.

[prkaye]

Thanks guys! Norman, that's exactly the kind of information I was looking for... thanks again!