Re: electric fuel pumps

Posted by HH56 On 2016/7/29 21:17:51

Most of us just use the electric pump for priming after a long sit or the occasional "vapor lock" situation. It should not be needed for routine running so I would wonder if the mechanical pump or other parts of your system are up to par. Perhaps something is restricting flow and the extra boost of the electric pump is overcoming some other issue.

If the mechanical pump has old rubber and you use ethanol fuel that could be a problem. There is also a screen in the bottom bowl of the mechanical pump which could be clogged. There is another screen in the carb under a large brass plug just behind the fuel inlet.

Some possibilities others have run into is the rubber hose between the steel line on the frame and pump might be old, internally cracked or has flattened due to a bend and has less flow capacity. If you have the optional ceramic filter next to the carb, if gas was allowed to dry out in the glass bowl varnish could have deposited within the filter element. The usual symptom there is reduced flow and the feeling of inadequate or running out of gas. Diagnosis is a bit hit or miss because air can pass easily leading to belief the element is clean but fuel flow is actually restricted. Frequently the glass bowl never fills up and car runs with a good portion of the element exposed.