Primer Line for O-360

[noema]

Wondering about the primer line. I am not sure how to connect it to the fuel system and where to run it.

Anybody found a good solution and has some photos to look at?

On a Husky there is a another AN T-fitting after the shutoff valve. From there a 1/8 copper line runs to a manual primer pump in the main panel. Then this line runs to the engine.

[N942VT]

https://www.summitracing.com/parts/sum-220677b

[Bissetg]

Do you need a primer? I never use one on an 0360 A4M or on the 0360 A1 EXP I had briefly. 4 shots on the throttle and they start every time.

[noema]

I wonder if this holds true for cooler climates. How low do you find starts with accelerator pump working consistently? Forums are full with pilots having problems. But maybe it is not if you know your airplane well?

[gregc]

Using the accelerator pump usually works but a properly designed primer system is safer. I don't really like an air box filled with fuel.

https://www.youtube.com/watch?v=TclflDhSZsk

[Bissetg]

We don’t operate much below freezing, -5 C would be it and preferably with pre heat at that. Gregc is right about a proper primer being the best option but I guess there are pros and cons that you have to weigh up including the risk of using the accelerator pump on an updraft carb. I decided the extra weight and complexity of the priming system wasn’t worth it, a point that is moot now that I’ve gone the IO path.

[rodsmith]

Will your engine have a boost pump? If so you can use a T downstream of the pump and a solenoid valve. Panel switch can have momentary on position that runs the pump and opens the solenoid, avoiding a manual primer pump on the panel.

[noema]

No boost pump planned. I saw the RV primer kit and luckily noticed it only works with a boost pump.

[noema]

This is what I came up with based on the parts available on ACS. Still not sure why the primer pump uses 5/16-24 male threads and not the standard female NPTs. Also the nozzle on the engine side uses 5/16-32 male threads. Kind of bothers me that I cannot use the same kind of parts as with the fuel and brake system. Maybe some of you know why or if there is a way.

• 1x 05-19920 primer pump
• 1x FAB-2-0-2 manifold (or FAB-5-0-2 all on one side)
• 1x 495004 pressure gauge adapter (summitracing.com)
• 1x AN819-6D sleeve
• 1x AN818-6D nut
• 1x AN833-2D elbow union at firewall
• 5x AN816-2D nibble
• 7x AN819-2D sleeve
• 7x AN818-2D nut
• 1x AN924-2D bulkhead-nut
• 1x AN913-1D plug
• 16x 03-40900 copper tubing 1/8x0.30 (16ft)
• 2x 61SM-02 nut at pump
• 3x AN4022-1 nozzle
• 3x AN800-2 union cone
• 3x AN805-2 union nut