Re: New member, setting off on a crazy adventure... PICS!!!

Posted by HH56 On 2017/11/22 12:56:02

A couple of other fuel considerations would be the state of the fuel tank. After sitting so many years it has probably got stale fuel which needs to be drained before even thinking of starting the engine. If the tank was sitting with water condensate it could also be very rusted inside and once you start messing around all those rust flakes will break free and start to come out and thoroughly clog the works. I would get the largest filter you can find and place it right at the tank outlet to catch any rust. Maybe carry a spare too. When draining the tank, the stock drain plug is steel and by now has most likely rusted to the tank bung. If you are going to try and remove it use a large vise grip, channel locks, or a pipe wrench to hold the bung as you work the plug. The bung is pressed into the tank sheetmetal and if you try to remove the plug and the bung breaks free and turns you have an almost impossible to repair leak in the tank.

As to the electrical pump, the mechanical pump has an output of 3.5-5 psi. The Airtex E 8902 has 2.5-4.5 psi out and would be suitable in totally replacing the original mechanical pump and being located in the engine compt.

Many permanently install an electric pump near the tank which can be turned on or off as desired. It is plumbed to push fuel thru the mechanical pump and filters to use in case of vapor lock or to prime after a long sit. For that application The E 8011 at 5-8 psi would be better due to the pressure loss resulting in pushing fuel thru the line and old mechanical pump..

In your proposed trip it is a quandary which pump to get to avoid wasting money and buying something not suitable down the road. With the old stock mechanical pump which due to age probably has old rubber, ethanol gas will most likely make short work of finding any weaknesses. Pushing gas thru the mechanical with damaged rubber would probably result in a crankcase full of gas if the diaphragm gave up during the trip. That is when you want to bypass the mechanical totally.

You could get the E8011 and mount it near the tank but if a failure happened and you needed to eliminate the mechanical pump, pushing that high a pressure directly into the carb could result in flooding due to high pressure pushing the float valve off its seat. That is where the E8902 would be better but mounting it at the rear for use long term, it may not have enough strength to push thru the mechanical should you ever want to have it as a backup only.

If you do contemplate a permanent arrangement of having fuel pushed thru the mechanical it is best to get a solenoid style pump such as the two Airtexes. The mechanical pumps can pull fuel thru them if they are off. Rotary pumps such as the Carter and some others usually do not permit sufficient fuel to flow thru if they are off and will require some special bypass plumbing to allow both pumps to coexist.