NO Boost pump in IV with Rotax 582

[jonstark]

I have a IV with a Rotax 582 installed per the early installation manual. There is no longer any instruction for the 582 installation from Kitfox. My build is totally gravity feed with NO ELECTRIC BOOST PUMP, just the impulse pump.

John McBean now says that "technically, there should be a boost pump".

What say you all?
Mandatory? Necessary? Smart? Don't fly without it?

Jon

[Av8r_Sed]

My decision was to install one. I also have a fuel pressure gauge to monitor how the Mikuni is performing. I haven't needed the aux pump yet, but it was cheap insurance.

[Dusty]

It would be wise to install an electric pump for the small increase in weight.
On when below 1500ft agl will give peace of mind.

[jonstark]

My decision was to install one. I also have a fuel pressure gauge to monitor how the Mikuni is performing. I haven't needed the aux pump yet, but it was cheap insurance.

Paul,
Is yours a Facet 2-4 psi pump in series? Where in the circuit did you put it?
Does it allow for gravity feed when switched off?

Thx

[jdmcbean]

Mis understanding.. We have the 582 installation instructions..However, it does not have the instructions for fuel flow test.


I have a IV with a Rotax 582 installed per the early installation manual. There is no longer any instruction for the 582 installation from Kitfox. Jon

[herman pahls]

I use a Facet fuel pump inline on both my 582 and 912 Kitfox's with pressure gauges.
Before start up I momentarily turn on the pump to make sure it is working.
I have had a fuel pump failure on the 912 and was glad to have the Facet backup.
It is nice to have a low fuel pressure warning like the Grand Rapids EIS.
Always flow test your system.

[Guy Buchanan]

I ran 500 hours behind a 582 with pulse pump and no backup. My backup was gravity feed. I also rebuilt the pump every year. They're pretty simple and pretty bulletproof.

[avidflyer]

I typed this before, and didn't post it. Avid aircraft determined through testing that the 582 would remain running if the pulse fuel pump quit if you had 1/4" ram air tubes pointing forward from your wing tanks. On my Avid MK IV with a Jabiru engine, I have no impulse pump, just an electric facet fuel pump that is only used for take off and full throttle purposes. I do have the ram air tubes as well. A couple of times I have taken off and forgot to turn the electric fuel pump on. Never noticed any difference in how the engine ran, although the few times it happened, I noticed my mistake and turned the pump on, once when I was probably 100' high. All that being said, you should for sure do a fuel flow test at the carbs to determine how much flow you get with just gravity feed. If memory is correct, you should have at least 1 1/2 times maximum fuel burn. I never had a second fuel pump on my other 3 Avids or 1 Kitfox either. Maybe I was just fortunate. Interesting note, I did have the Jabiru supplied mechanical fuel pump over power the float valve, and that caused the engine to flood when pulled back to idle. That caused one of my dead stick landings. That was what caused me to go to the electric backup and gravity feed. Not exactly your question though I guess. JImChuk

[jonstark]

Thanks for the replies guys!

Do your pump installations have a hi-flow check valve in parallel with the pump? Fuel won’t get thru a Facet unless it’s running will it? Or is there a “bypassing” or full flow type Facet?

Jon

[avidflyer]

I don't know about other model facet pumps, but mine is in the one line coming from the header tank behind the seat. Gravity feed flows through it no problem. JImChuk

[DesertFox4]

The Facet on my model 4 912 uls gravity flowed with no problems.

[jonstark]

I’ve got to figure out which kind of pump those are. I have one on hand that would act as a shut-off valve if not running.

Jon

[avidflyer]

Here is a link to one that may suit your needs. I don't remember off hand which one I have in my Avid. JImChuk
https://www.pegasusautoracing.com/productdetails.asp?RecID=82

[jonstark]

I’ve ordered a 40104 and a bunch of #5 hydraulic fittings. Thanks for that but Spruce was cheaper for the pump and got the ftgs too.

Jon

[Av8r_Sed]

Sorry for the later response. I think that's the pump I have, installed as JimChuck has done. You want low pressure so it can't overpower the float valves in the carbs.

[jonstark]

I installed the Facet pump before the fuel shut-off as there wasn’t enough room to easily shoehorn it after. Would have made replacement easier in the future but with only 12 gallons I can drain the system in a jiffy.

The engine starts far easier! Nice benefit. (I have no primer)

Gravity fuel flow virtually unchanged with the Facet pump too.

Jon