Engine primer source
 

For those of you with the Vans electric priming system and don?t have a gascolator on the firewall, where did you pipe the feed fuel to the solenoid from ?:confused:

I guess I wasn?t very clear in my question. Installing Vans primer on carbureted engine and I don?t have a gascolator. Wondering if I should put it before or after the engine driven fuel pump. Thinking if the solenoid stuck open if installed after the fuel pump, it would make the engine run wild. If the solenoid failed open if installed before the fuel pump, the pump would suck air or at least loose suction. Now I?m thinking I should install before the fuel pump and put a check valve in line at the solonold to prevent engine failure if the solonold should fail open. Just trying to work this out. Not really fond of throttle pumping to prime. Though someone would suggest a solution.:)

Why not put a "T" fitting on your firewall such that the fuel to the carb goes through the straight part of the "T" and the primer is fed from the leg of the "T"?

This would put it downstream of the electric pump but upstream of the mechanical pump.

That basically replicates the gascolator install, doesn't it?

Kyle that is exactly what I?m planning to do. Found a AN 6 coupling with a 1/8? tap for the primer that Im installing at the suction side of the pump. Thanks for your imput. There?s a lot of guessing going on here and I guess Im looking for some reassurance that Im not screwing up. :rolleyes:

Any details of fitting
 

Hi Tom ... need the same fitting ! Any details . Part # , where you bought it , picture ? Thanks. Stew

Tom...
Kyle said at the firewall. You are saying at the fuel pump...if I am reading right. Pretty sure you are mounting the solenoid on the firewall. Remember every time you connect a firewall mounted item to the engine, you use a flex line. so be careful about keeping your system neat and tidy. The TEE at the FW then run to the solenoid then the flex line to the engine, seems to keep it cleaner. Just my .02.

I purchased all the steel fittings from Aircraft Spruce and the flex hoses from TS Flightlines. Had my aircraft inspected by Vic. Systems works great with no problems. Quarantined now and can?t get to the hangar.:mad:
TS Flightlines also sells the fittings . Tom at TS was extremely helpful and his service is about the fastest and highest quality around. Ended up teeing after the engine driven fuel pump and running a SS / Teflon firesleeve hose to FW mounted primer solenoid valve. From there another SS/ Teflon firesleeved flex hose to primer line manifold on engine. Having a flexible connection is very important since the engine physically moves so much. I?ll check it when and if I ever get to it again and get some photos and numbers if you still need them.

Tom,

Sounds like you're finished and happy with your installation but perhaps this will help someone else in the future.

I removed a 1/8" NPT plug near the fuel inlet on the carburetor and ran a flexible hose (also from TS Flightlines) to the primer soleniod mounted on the firewall. No fittings required outside of a 1/8" NPT-to-flared-tube nipple at the carburetor.

When the solenoid is activated there's good primer fuel pressure from the engine-driven fuel pump while cranking and even better pressure when the boost pump is running.

Your concern about a leaky solenoid is valid because the engine runs very rich (but mine does run) with a solenoid that is not completely closed. I learned this when I installed the fuel solenoid "backwards". The three primered cylinders were excessively rich and the engine would not stop at idle-cutoff. I did not realize that the primer solenoid has "polarity" and it matters which port is input and which is output. It's mentioned in the Overview and the Q&A on the Aircraft Spruce web page.

--
Joe

Thank god for you guys !!
 

Joe and Tom. Thanks so much as your sharing here saved me a whole bunch of rework ! Going to do as Joe did from the pity on the carb that used to be fuel pressure line to gauge ! Saved just a bunch of work and I like the idea of being on the engine side of the fuel pump .... I guess however that if the primer line fails we will be spraying fuel into the cowl ( scary ) at fuel pump pressure ? If primer line same off before pump thinking that since the primer line is very small that pump wouldn't suck too much air ... ok. Now I am not sure which is lesser of two evils ?? Have I got that right ?? Thanks. Stew

I tapped my system near the gascolator. I felt it was safer to have an air leak on the suction side vs spraying fuel on the pressure side in the event of failure. primer works off of the boost pump. I can't think of a reason to use the primer in a situation where the engine is spinning and therefore the eng fuel pump is providing pressure.

Larry