proper fuel pump vacuum - v6-200

[allemann]

my carbureted engine is actually on a Sportjet 175XR2.<br />I was wondering if anyone knew what is adequate amount of suction on the fuel pumps (or link to where to look it up)? On this engine, the mechanical pump is showing about 2" of hg, and the electric priming pump (only while cranking) also shows about 2" hg. It doesn't seem like very much suction to pull fuel through a filter and the check valve in the priming pump. My vacuum gage is kind of a cheapie, but I think it is reasonably accurate.<br />Thanks<br />bill

 

[rodbolt]

Re: proper fuel pump vacuum - v6-200

sounds about right<br /> the max is about 6"Hg at wot. much more and the fuel may boil in the lines.

 

[allemann]

Re: proper fuel pump vacuum - v6-200

I found the problem. The 3-way tank selector valve had an internal leak. The spare tank happened to be empty and the valve was leaking to that port when the other tank was selected. Kind of hard to find because all the connections, etc were good.<br />Thanks<br />Bill

 

[rodbolt]

Re: proper fuel pump vacuum - v6-200

that is where the clear plastic tubing on your vacum gauge is handy, you can watch the air bubbles come through the line.