Fuel Primer Line

[whee]

When using the BH gascolator where do you connect the primer line to the main fuel line? Seems like just Ting in would create a potential to suck air into the system. All the systems I'm familiar with there is a primer port on the gascolator but I see the BH gascolator does not have this port.

[BTAZ]

I built a gascolator from the "plans"(term used very loosely) shown in the LSA build book. I drilled/tapped an extra 1/8" pipe port for the primer next to the main outlet.

As an alternate, when I was looking at various build photos, I saw at least one installation where the primer drew from a T installed close to one of the T's that tie the front/rear tank outlets together. IIRC, it was in the line coming down from the front tank outlet. I expect that would work just as well and might even make routing of the primer feed line easier.

This latter approach is probably the one I would have taken if I hadn't already taken the first approach.

Of course, my system is completely gravity feed so no pump that could "suck air".

If fuel injected, with an engine driven and a separate boost pump, my thoughts would be "What happens if the primer or any of its lines start to leak?" and let that guide the approach.

[Mark Moyle]

I built a gascolator from the "plans"(term used very loosely) shown in the LSA build book. I drilled/tapped an extra 1/8" pipe port for the primer next to the main outlet.

As an alternate, when I was looking at various build photos, I saw at least one installation where the primer drew from a T installed close to one of the T's that tie the front/rear tank outlets together. IIRC, it was in the line coming down from the front tank outlet. I expect that would work just as well and might even make routing of the primer feed line easier.

This latter approach is probably the one I would have taken if I hadn't already taken the first approach.

Of course, my system is completely gravity feed so no pump that could "suck air".

If fuel injected, with an engine driven and a separate boost pump, my thoughts would be "What happens if the primer or any of its lines start to leak?" and let that guide the approach.

Boost pump acts as the primer on fuel injected engines.


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[whee]

Boost pump acts as the primer on fuel injected engines.

Unless the battery is dead. I would like to have the option of hand propping so I'll need a primer.

[Mark Moyle]

Ah! Hadn't thought of that.... You can use one of these on the output port of the gascolator. https://m.summitracing.com/parts/rus-670063

Then run the 1/8 copper line to the primer with the 1/8" NPT ferrule fittings..

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[whee]

Thanks Mark. That fitting looks like it might be a good way to do it.

I just looked up the Cessna 185 manual primer and they attached the primer line to the gascolator. I'm not sure I'm entirely comfortable with that.

[Mark Moyle]

On my pacer the primer line fitting is an 1/8" NPT fitting on Steve's aircraft gascolator. The gascolator is mounted to the engine side of the firewall. The primer line route is up the firewall to a penetration...then to the primer.... Just another fuel line that needs to be supported and protected from anything that it may come into contact with. The 63 year old copper line in my Pacer had quite a few areas where it had nearly rubbed through.... The only thing I don't like about Pipers primer line routing is....two lines through a grommet on the firewall.....and all the grommets were deteriorated. Perhaps consider making firewall penetrations using stainless plate and tube with fire sleeve. Anywhere a fuel line may come into contact with something....Multiple layers of heat shrink tube.


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[Zzz]

Unless the battery is dead. I would like to have the option of hand propping so I'll need a primer.

There's no excuse to be dead battery with all the cool EarthX stuff. Dual lightweight batteries, and their jumpstart mini-battery pack.

But, shit does happen.

Why is copper tubing using for primer lines anyway? I had a copper oil pressure sender line snap on me a while back, dumped most of my oil. Isn't there a more flexible/resilient alternative?

[Bdflies]

"Why is copper tubing using for primer lines anyway? I had a copper oil pressure sender line snap on me a while back, dumped most of my oil. Isn't there a more flexible/resilient alternative?"

I've wondered the same thing. Only answer I could guess is because of the tIny little primer fittings that go into the intake ports and the little brass nipples that have to be brazed onto the lines. Because the fittings are brass, material choices are limited. I suppose one could use completely different fittings and use some sort of flex hose...

Another question has popped up, though. If the injection nozzles are in the intake ports of an injected engine, where would one put primer fittings to prime each cylinder?

Bill

[whee]

I setup the firewall for dual battery boxes and I have thought that rather than a primer a mini jump battery would be good but what if...

I'm not sure why copper tube are used. I'll be using stainless steel...I think.

On the Continental IO360 there are two ports in the intake tubes that the primer feeds to.

[JimParker256]

Just saw a thread over on "another forum" where they discussed copper fuel lines on an older Cessna. There was an AD (many years ago) that mandated replacement of the copper fuel lines, because they have a tendency to work-harden and crack. Under pressure, they spray fuel all over the place. I believe the FAA banned them from any newly certified aircraft some time back. I plan to use something else.

[Mark Moyle]

Just saw a thread over on "another forum" where they discussed copper fuel lines on an older Cessna. There was an AD (many years ago) that mandated replacement of the copper fuel lines, because they have a tendency to work-harden and crack. Under pressure, they spray fuel all over the place. I believe the FAA banned them from any newly certified aircraft some time back. I plan to use something else.

Wish I would have known that when I rebuilt the pacer.... On the Pacer my preflight check list included checking the copper lines to each fuel primer.....due to how easy it is to open up the cowl...On the Bearhawk...with that Acclaim cowl...the oil dip stick will be the only thing easily accessed during preflight inspection. Not using a carbatrator.....


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[Zac Weidner]

On my pacer the primer line fitting is an 1/8" NPT fitting on Steve's aircraft gascolator. The gascolator is mounted to the engine side of the firewall. The primer line route is up the firewall to a penetration...then to the primer.... Just another fuel line that needs to be supported and protected from anything that it may come into contact with. The 63 year old copper line in my Pacer had quite a few areas where it had nearly rubbed through.... The only thing I don't like about Pipers primer line routing is....two lines through a grommet on the firewall.....and all the grommets were deteriorated. Perhaps consider making firewall penetrations using stainless plate and tube with fire sleeve. Anywhere a fuel line may come into contact with something....Multiple layers of heat shrink tube.


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Is your pacer original with the cables and pulleys on the control column? Our '58 has a roller chain and sprockets down almost to the floor where they connect to cables.


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[Mark Moyle]

Is your pacer original with the cables and pulleys on the control column? Our '58 has a roller chain and sprockets down almost to the floor where they connect to cables.


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Yes, 1950 Sn 20-174


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[whee]

Battson I've been looking at pics of your fuel system and I can't see a primer line. Do have a manual primer? If not, have you missed it at all?