[ROVERNET - UK] Fuel Pump woes

geffandjulie geffandjulie at comcast.net
Wed Aug 3 06:21:43 BST 2005

US 3500S all have an electric pump mounted alongside the fuel tank, covered 
by a foam insulator.  The mechanical pump is not there and is blanked out by 
a triangular plate.  The reason is said to be fuel starvation from boiling 
in the lines in hot temperatures. The mechanical pump could not overcome it. 
The hood louvers were added simultaneously for the same reason. Racy...but 
really to keep it turning over in summer.
----- Original Message ----- 
From: "S Manwell" <smanwell at sprintmail.com>
To: <lacpsyd at earthlink.net>; <rovernet at lyris.ccdata.com>
Sent: Tuesday, August 02, 2005 4:14 AM
Subject: Re: [ROVERNET - UK] Fuel Pump woes

> Lance,
> I'm not too familiar with 3500S specifics, but I think the Federal 3500S 
> may have had a US-made Facet electric fuel pump.  I think you might be 
> able to get the same pump at a NAPA autoparts store or similar.  Also, I 
> wonder if there is any restriction in the straw that the pump is sucking 
> from...
> --Steve
> Lance La Certe wrote:
>>Hi Gang,
>>Need help with fuel pump and discovered some info that may be helpful to
>>others on the list.
>>1) 1970 3500S ----I'm in need of a new fuel pump.  Any suggestions for a
>>state-side source (I will be contacting Ruth Burgess in Canada)
>>2) I need to know if anyone can give me the specs on the OEM fuel
>>pump----specifically what are the upper and lower pressure limits (e.g.,
>>2.5 psi to 4.5 psi, etc).
>>3) For several months I have struggled with the car not being able to idle
>>once the engine was at normal operating temperatures (especially in the
>>summer when it has become especially hot).  After many helpful suggestions
>>from the listers (e.g. blow out the return fuel lines; check the
>>circulating coolant line which runs directly into the intake manifold;
>>check your timing, etc)-----I discovered that when cold and just starting
>>that my fuel pump was putting out only about 3 psi-----this was adequate 
>>keep things running smoothly, but after several minutes of running, as the
>>fuel pump becomes warm it actually becomes less efficient (apparently most
>>all fuel pumps operate this way----hence the listed range on the specs). 
>>As it turns out, when warm (and this has nothing to do with the engine
>>temperature, but the pump temperature), it was only putting out 1 psi.  At
>>this pressure there is not enough flow into the carb bowls to overcome the
>>tendency for the gas to vaporize, especially when the engine is warm/hot. 
>>With a properly operating pump which is keeping the pressure up, it should
>>overcome the tendency to vaporize and allow the engine to continue to 
>>4) My mechanic is suggesting that I find a pump that will put out about 7
>>psi when cold, so that when it heats up it will still be putting out about
>>3 psi to overcome the vaporizing problems.
>>Any help with this would be appreciated.
>>Lance La Certe,  Denver, CO
>>Lance La Certe
>>lacpsyd at earthlink.net
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>>rovernet at lyris.ccdata.com
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