Manifold gauge connections

[pilot-as14]

Hello, 

I'm wondering where the manifold fuel vent connections should go? Can someone tell me? Does it have to be a pipe or a hose?

Thank you in advance!

[47U]

4 hours ago, pilot-as14 said:

I'm wondering where the manifold fuel vent connections should go?

There’s no fitting or tubing/hose installed on that vent on my C.  I don’t think there was ever anything there.  The IPC doesn’t show anything installed on the vent, only the fitting, line, and snubber to the pressure side.

I suppose if you were motivated, you could install a fitting and route it overboard as a case drain, as a caution that the fuel pressure gauge failed internally you wouldn’t be dumping raw fuel behind the panel.  But, the fuel pressure reading could be affected, I’m guessing.

I’ve never heard of a fuel pressure gauge failing internally on a Mooney (anyone?), but I supposed it could happen.  I’d be more leery of the fuel pressure hardline from the firewall to the gauge.  Mine got broke during some avionics work.  I made a new one and used it for awhile, then ultimately decided I didn’t like it so I replaced it with a hose.   

Even better would be to upgrade the engine gauges to glass and get pressurized fuel and oil lines and hoses out the cockpit altogether.  Someday.

[00-Negative]

I replaced my 1966 M20E original gauge with a used gauge from a 1968 M20F that has the fuel vent line. We routed the hose thru the firewall and over the left cowl flap next to the oil breather outlet. Worked great for the first few flights. Then the fuel pressure started reading high and works remain at 14 even after shutdown. The vent hose had melted shut due to it's proximity to an exhaust pipe. Even after cutting the distal melted portion off and restoring patency of the vent hose, the erroneous reading persisted. I had my original gauge which does not have a fuel vent outlet  overhauled and reinstalled. 

- David

[pilot-as14]

I thank all friends who answered my question with Manifold. It helped!