Do I need primer? (Fuel, that is)

[szicree]

I just built a new carbed XP360 with lightspeed/mag with the standard primer lines but am wondering if it isn't just one more thing to leak. I'll be based in SoCal and am hoping to hear from those running similar engines. Do you need a primer or is a squirt from the carb adequate? Thanks.

[Brian Vickers]

Steve,
I don't know if you need it or not but I'm not installing a primer system. The two RV owners I know in my local area (Bremerton, WA) don't have primer systems on their airplanes either. I'm working on my panel right now and have plenty of room to add a switch if needed. I have been ordering parts from Van's lately and the fellow that has been helping me also suggested I omit it. He said to add it later if needed. It doesn't get that cold here in the winter.

Sincerely,

Brian Vickers, RV4 finishing

[osxuser]

No, just two-three throttle pumps before starting.

[McFly]

I have a three line primmer on my engine.

My primmer seems to be good for making the engine backfire at startup but that?s about it. I never use it anymore and the engine starts fine.

My engine stated to lightly stumble intermittently on the Friday's flight (I doubt a passenger would notice). Turns out the T connection to the primmer line had become disconnected. I am going to rip it out as part of my first Condition inspection. It is dead weight on my plane for my neck of the woods. Good luck.

[gmcjetpilot]

Check the archives, search\/ above on fuel primer. Lots of opinions. Did a quick search for you. My thought? You can always put it on later, but don't "carb prime" using the accelerator pump in the carb indiscriminately. Some carb prime only when turning the engine if possible.

The traditional thing is to put a primer on, but leaving it off saves a lot of weight, clutter and potential future maintenance issues.


http://www.vansairforce.com/communit...ghlight=primer

http://www.vansairforce.com/communit...ht=fuel+primer

http://www.vansairforce.com/communit...ht=fuel+primer

http://www.vansairforce.com/communit...ht=fuel+primer

http://www.vansairforce.com/communit...ht=fuel+primer

[billnaz]

The Lyc. throttle accellerator pump is all ya need. Only pump the throttle while the engine is turning over though.

[dwilson]

Originally Posted by billnaz

The Lyc. throttle accellerator pump is all ya need. Only pump the throttle while the engine is turning over though.

I agree with the "pump only when the engine is turning over" idea. A local RV-4 owner had a small fire when he pumped before kicking the starter over.

My RV9A O-320 starts easily with one or at most two pumps from the throttle while cranking. Only been flying since Mar. 07 in the Pacific Northwest so can't comment on really cold situations.

Duane

[Ron Lee]

Then when a line fatigued I removed the whole thing. No problems starting even when cold but I do preheat (oil sump heater) my engine.

[Bob Axsom]

I guess the choice is up to you. I have a primer solenoid in my console downstream of the aux. fuel pump. I put a full loop in ever 1/8" line of the system between the firewall and the engine and it works perfectly with no failures to date, ~350 hours. I bought one of the small butane torches from Aircraft Spruce to install the AN800-2 union cone on the ends of the primer lines. It was fairly simple to do and there isn't much to it.

Bob Axsom

[robertahegy]

For SOCAL, forget it. For Alaska, maybe.