apkp777

apkp777

Well Known Member
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.]
 
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.
 
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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?
 
apkp777 said:
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?
Click to expand...

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.
 
Yes in the NE USA

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
 
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?
 
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!
 
Hard to Calibrate Though

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
 
Engine Heater

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
 
I'll take the priming system any day, rather than pumping the throttle for a cold start. It has worked very well. And I do have a hole in the FAB too.

L.Adamson --- RV6A
 
primer

my used o-320E2A came with primer plumbing to 3 of the cylinders.

the carb also has an accelerator pump.

I plan on installing a solenoid operated from a switch on the panel.

I'll post my experiences with it (and more) when I get this project in the air
(hopefully in the next 6 months):eek:

Dave
-9A finish kit
N514R reserved
 
I went with primer--Have carb with acc pump, but with ease of install, if needed it is avail. Note, long ago had failure :eek: of BOTH mech and elect boost pump, my plunge primer ( 3 cyl) supplied enough fuel to make airport--would not be without ever since.
 
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Priming Procedure?

For those with primers (I have O-360 with Asco electric primer solenoid), what start procedure do you use (normal or cold)? Is it 3 seconds on the primer then ignition?
 
Yes, fires do happen...

due to over-priming using the accelerator pump. I saw it happen to a Cessna 172 on our ramp. The pilot who did it, is very 'heavy' on all his controls... he really slams the yoke and throttle from stop to stop. It was a hot summer day here in S. Fla. and he primed his engine even though the engine was already hot. Burned up everything FWF. Even though fires are rare, I learned that you should always prime with the primer, not the accelerator pump. Too much accelerator pump and fuel pools in the air intake and then all it takes is a backfire.
 
Crank BEFORE Pumping!!

OK, if I was living up north, I'd be using my primer solenoid more often, but down here where it's warm, a few throttle pumps is all it takes if the temps are below 70 degrees. But....and this is REALLY important, you can't tell someone to "pump the throttle, then crank"! This is a guaranteed way to make a pool of fuel in the FAB, and quite potentially hazardous.

If you're going to prime with the accelerator pump, you need to get the big suction pump (the engine) going to draw the sprayed fuel into the engine FIRST! Crank, THEN pump, and don't pump if you're not cranking! This is how the "old wives tale" about fires got started - because it is true, if you pump, then crank. If the engine is sucking while you pump, it draws the fuel right into the cylinders and makes fire where you want it.

OK, I've repeated myself enough - sorry. I'll just add that down here in the warm climes, I have used the electric primer solenoid once in 1,000 hours on the RV-8. Louise's -6 has no primer system at all (and it came from Oregon) - so yes, you can easily build without one. The disadvantage of a primer is leak potential - so if you build one, do it right with lots of strain relief and flex loops.

Paul
 
Fuel primer

You can use one switch (S700-2-50 if I remember correctly) to control both the fuel pump and fuel primer. Down position is off, middle position is fuel pump, up is momentary on for primer. The switch is the on the bottom left row 4th from left.

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Gary
RV7A - 670 hours
715AB
 
Today in upstate NY (1B8)

33F - snow on ground - 25 minute preheat with propane - 8 sec prime - start on first turn

I'm just about to order a Rieff system so that I don't need the propane.

1b833f.jpg


Jim Sharkey
RV6 - Phase 1
 
jsharkey said:
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
Click to expand...

This was easy to figure out for me. After turning on the fuel pump I let the system pressurize...that way I know there's fuel in the line by the solenoid. At that point, I hold the solenoid switch open for 7 seconds, then shut it and the fuel pump off. Starts right up. :)
 
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