Electric fuel primer...is it necessary?

apkp777 · #1 12-05-2009, 06:06 PM

Hey all - I am not seeing a fuel primer on many installations. Anyone have any experience in a cold Wisconsin winter without a engine priming system? I know many of the planes I fly as a CFI would never start without it. I can't imagine if the RV is any different.

[For the record, I am installing a non-fuel injected, P-mag equipped o-320.]

Geico266 · #2 12-05-2009, 06:09 PM

If your carb has an accellerator pump no primer is needed. Pre heat, turn on the electric fuel pump to build pressure and a few pumps of the throttle, should start in one turn. On the other hand it is nice to have a primer if you can't pre-heat, saves wear and tear.

apkp777 · #3 12-05-2009, 06:17 PM

I guess that the carb I am getting with my engine has an accelerator pump. Don't know for sure? Still, is it worth it to add the Van's primer or not?

Geico266 · #4 12-05-2009, 06:30 PM

Quote:

Originally Posted by apkp777

I guess that the carb I am getting with my engine has an accelerator pump. Don't know for sure? Still, is it worth it to add the Van's primer or not?

I would for sure. It's not the start that you have after preheating that worries me. It's the start when you are parked overnight somewhere else with no heat.

jsharkey · #5 12-05-2009, 06:31 PM

My primer wasn't working at first. When I got it fixed - bad crimp on the ground wire - my YO360-A1A started a lot easier.

As for the accelerator pump I've been told to be careful not to over do it as it can pump fuel into the air filter bowl which can catch fire if there is a backfire on start up - not sure if that's an old wives' tale. Good reason to remember the drain holes in the filter bowl though.

Jim Sharkey

apkp777 · #6 12-05-2009, 06:55 PM

I don't see any downside to installing the primer system, just wanted some input. Van did a great thing putting the battery so close to the starter. I am sure that you can really spin the prop, even on a cold day. Cessna has a similar set up and still it's hard to cold start.

I just haven't seen a whole lot of photos on others RV's with the primer switch. Perhaps because most are F.I. and the others were in warmer climates.

I think I'll just move south and save the $130 for the kit, what do say?

lostpilot28 · #7 12-05-2009, 07:08 PM

I was questioning the need for the primer solenoid, too...but in the end I added it and use it every time I crank the engine. I've never tried to start without it, but on cold days I can't imagine it would start right up...especially with the carb on the bottom.

Also, the thought of fuel pooling in the FAB bothered me!

N941WR · #8 12-05-2009, 07:29 PM

Quote:

Originally Posted by lostpilot28

...Also, the thought of fuel pooling in the FAB bothered me!

That's why you are supposed to drill a hole in the bottom of the FAB, to let the fuel drain out.

jsharkey · #9 12-05-2009, 07:36 PM

It's easier on a Cessna to gauge how much to prime with the syringe pump - you can count the strokes AND "feel" the fuel. With the solenoid you can "count potatoes" as you press the button but still haven't a clue how much fuel is or isn't flowing.

Lots easier to install I imagine than a traditional system.

Jim Sharkey

JoeLofton · #10 12-05-2009, 07:46 PM

Highly recommend installing a heater pad on the oil sump. The warm engine helps vaporize the fuel from the accelerator pump and makes starting much easier. My RV-3 (O-320, carb, no primer) is hard to start when cold-soaked down around freezing.

...Joe