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Is an electric primer needed for a fuel injection?

rv6ehguy

Well Known Member
Good evening fellow RVators,
I am just planning the switches I will need for my panel build. A while back, someone told me that I would not require an electric primer for my fuel injected engine. Can someone with more knowledge than myself verify this?
Cheers.
John Van Lieshout
[email protected] wz(underscore)bang(at)hotmail(dot)com
RV6A 85%
Aerosport IO-375
G3X 3 screen
C-FMYM (reserved)
 
That's right. The fuel injection itself like serve the use of the primer. By running the boost pump you will dump fuel in the same ports as the primer would.
 
Primer

Just to be clear. If you have a fuel injection system which includes the electric boost pump a separate primer system is not needed or required. All cold or hot start priming is done with the boost pump.



Don B

RV 9 Rebuild in Progress
 
Just to be clear. If you have a fuel injection system which includes the electric boost pump a separate primer system is not needed or required. All cold or hot start priming is done with the boost pump.



Don B

RV 9 Rebuild in Progress

That is correct
 
Only use the aux fuel pump to prime then shut it off and proceed with the recommended starting procedure.
 
thanks

Thank you everyone for your quick replies to my question. This place is a mountain of information. Cheers.
John Van Lieshout
[email protected] wz(underscore)bang(at)hotmail(dot)com
RV6A 85%
Aerosport IO-375
G3X 3 screen
C-FMYM (reserved)
 
primer for fuel injected engine

There is one situation where you do need a primer with a fuel injected engine: if your battery is dead and you need to get home you can start it by hand-bombing IF you have a mechanical, hand operated primer (not electric). If you do not have a primer, you can not get it started. I was going to put one in my -8 but decided not to because usually there is someone around to give you a boost. If you land on remote strips it could be a problem.

MAL RATCLIFF
 
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To expand on using a "boost" electric pump for an I/O engine. To start 2 or 3 seconds "on" boost pump to prime I/O system, turn off.. Start engine. Switching tanks in flight, boost pump on until switch completed, then off. While on final to land boost pump on until landing completed. Would this be a correct procedure?? Mark C.
 
As long as you are in the planning stage it is helpful to add 1 or 2 switches and or breakers and call them "Spare"
 
Switching tanks in flight, boost pump on until switch completed, then off. While on final to land boost pump on until landing completed. Would this be a correct procedure?? Mark C.
This would definitely NOT work on my fuel injected engine. The boost pump would flood the cylinders with too much fuel. Anything less than full throttle and you would kill the engine (ask me how I know).
 
This would definitely NOT work on my fuel injected engine. The boost pump would flood the cylinders with too much fuel. Anything less than full throttle and you would kill the engine (ask me how I know).

Yeah, but like Scout said, it's a morphodite ;)
 
This would definitely NOT work on my fuel injected engine. The boost pump would flood the cylinders with too much fuel. Anything less than full throttle and you would kill the engine (ask me how I know).

Just curious...why is that? Is this with a Lyclone or something else?
 
Just curious...why is that? Is this with a Lyclone or something else?
well, I have an ECI IO-340 with the eci constant flow fuel injection. I have had the experience of taxiing after landing and accidently flipping the boost pump switch on. The engine immediately died.
 
well, I have an ECI IO-340 with the eci constant flow fuel injection. I have had the experience of taxiing after landing and accidently flipping the boost pump switch on. The engine immediately died.

This doesn't sound right...and sounds hazardous, since it could happen in flight.
 
Switching tanks on my RV and any other certified aircraft with injection I have flown always worked with the pumps on.

On my RV Normal fuel pressure is 23 psi and when the pump is on it is about 32 psi.
Never have had any problem in flight and if it did present a problem I would say you have a problem..It should not flood out the engine.

What would you do if you had an ran a tank dry... not turn the fuel pump on? and switch tanks?

In fact I have never heard of a situation where when an engine is running and the fuel pump was on it would cause the engine to quit.

Pumps on for takeoff? Yes.

My 02c worth.
Jack
 
I'm smilin' with Jack. Every fuel injected engine I have flown gets boost pump for takeoff and landing. Never gives even a hiccup to the engine. Maybe your pressure regulator (often part of the pump assembly) is set too high or somehow blocked.
 
Steve's ECI injection is nothing like a Bendix injection. A Bendix-pattern fuel control (Precision and Airflow Performance) is, by design, insensitive to fuel inlet pressure. The ECI unit is more like a Continental injection, with an engine driven vane pump to make fuel flow more or less proportional to RPM.

http://eci.aero/pdf/FISbrochure.pdf

That's why I was kidding Steve about it being a morphodite on a Lycoming.
 
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Hey Dan,
I will still differ with you..:). but just something to consider..

ON the link you provided for ECI... they state in the questions and answers that an electric driven boost pump is used for starting and emergencies.

Also they state that the boost pump that Van's supplies is adequate.

It is also shown in the fuel diagram in the lower portion of the page.

The only aircraft that I ever had that if you used boost pumps to start it would flood the engine since 2 pumps other pumps were hot wired and they would be on continuously was on a volpar conversion H18 nose wheel Beech 18 with radial engines of course. As I caught the ramp on fire at Tallahassee one night on a freight run.

Even on my Superior XIO360. I have an electric boost and engine driven pump... exactly like the fuel diagram ECI described. And never had a situation where it appeared the engine would quit if I put the pumps on in flight.

If you compare it to a continental engine.. such as IO 470's, IO520's, IO 540's on Cessna's and Beech's it would appear that on those aircraft such as 310 you used the pump during Starting, fuel tank switching from inboard to tip tanks. but you could burn off either tanks. Switching on a 310 to the inboard tanks would not only allow you to fill the tips back up but also provide fuel for the engines. plus move your CG around.

Be honest It's been a long time... since the old 310, B56TC days. I would have to pull out a pilot manual and see about landings. 1973-78 is a long time ago.

Just food for thought...

You might be correct... or their might as Jesse stated be a problem.

Smilin' Jack
 
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