Fuel consumption and flow rate

[Phil Waterman]

Hi

Been reading this thread with interest as the increasing levels of ethanol in gas is a problem. In the USA they are looking at going from 10% to 15% which I fear will lead to a new round of problems.

In the US they had to change the Marine Primer Bulb composition a couple of years ago as at that time marine gas didn't have ethanol and vehicle gas did. There was a round of problems caused by people filling their boat tanks at the local gas station. So if you are going to add a primer bulb be sure to check that it is rated for ethanol.

I have discovered one other problem with marine primer bulb connected in line with electric fuel pump. Testing engines on the test stand I discovered that if the bulb doesn't get completely purged of air that the electric fuel pumps may not be able to suck the fuel through because of the cushion effect of the air and the rubber bulb is just enough to absorb the individual strokes of the electric fuel pump. Once the bulb is purged of air this problem seems to go away. Found the problem by putting a combination fuel pressure and vacuum gauge on either side of the bulb to note the difference.

A higher flow electric or mechanical probably would not have this problem.

Wasn't there an electric fuel pump that was used in some of the Ford CMPs to help cure some fuel supply and vapor lock problems?

Cheers Phil