Replacing fuel pump....stick w/ willys type w/ glass bowl or

davpet · Post by **davpet** » Wed Jul 05, 2006 9:08 pm

go modern. What would be a suitable replacement fuel pump for an L head 134 engine?? My 49 CJ3A must be leaking fuel through the diaphram directly into the oil pan. Will the new pump w/ glass bowl be able to withstand the new fuels w/o destroying the diaphram?? Anyone have a "modern fuel pump" that would still work on the old Go Devil engine??

thanks,

Dave Petrella

Post by **wesk** » Wed Jul 05, 2006 11:49 pm

The correct Willys # 647911 or AC # 1539353 when used after a modern overhaul is all you need. The correct spacer for this pump is WO# 647669, approx. 1/8" thick. If you elect to sub a different pump you must use the correct thickness spacer for it from it's original installation.

Review Harolds 3A page Fuel Pump Article:
http://www.cj-3a.com/Fuel%20Pumps.htm

Ryan · Post by **Ryan** » Thu Jul 06, 2006 11:30 am

When my original vacum pump failed I went to the local parts store and ordered a pump for the L134. (It is no longer a vacume pump.) Best I could tell I did not have to use the spacer from my old pump. If I held the new one up to the old one with the spacer installed on the old on the arms looked to be the same length. My pump does not have the glass bowl. The engine runs well I hope I havent messed anything up?

Post by **wesk** » Thu Jul 06, 2006 11:57 am

The primary purpose of the spacer is to adjust fuel pressure by changing the pump arm's position relative to the cam. If you are using a pump Part No so and so and it is being used on an engine model so and so and it was used with a specific thickness spacer then to keep the fuel pressure where it should be you have to match the parts.

When you take off on a tangent and use a diiferent pump then specified all you need to do is measure the pump's pressure output and if it's not in the ball park adjust with spacers.

Post by **Ryan_Miller** » Thu Jul 06, 2006 6:37 pm

I have seen people use aftermarket low pressure (high pressure being for fuel injection and not carbs) electric fuel pumps and bypass the older style pump.

Just a suggestion for someone who doesn't want to deal with a fuel pump that has diaphrams that the newer fuels may break down.

Post by **wesk** » Thu Jul 06, 2006 8:43 pm

An electric pump conversion is really not necessary in most cases. You will loose the necessary vacuum boost for the vacuum wipers when you switch to electric.

davpet · Post by **davpet** » Thu Jul 06, 2006 8:55 pm

Wes,
my CJ3A had no windshield or wipers when I bought it.....would it be possible for the fuel pump if it was the vacuum type, to be plugged to prevent any problems caused by vacuum pressure. (sorry this didn't even sound coherent when I was thinking it.) is there a problem having a vacuum assist fuel pump but nothing to use that vacuum pressure for??

Dave

Post by **wesk** » Thu Jul 06, 2006 9:15 pm

Yep it will work. Just don't plug the fitting holes up.

Cacti_Ken · Post by **Cacti_Ken** » Fri Oct 14, 2011 11:06 am

wesk wrote:The correct Willys # 647911 or AC # 1539353 when used after a modern overhaul is all you need. The correct spacer for this pump is WO# 647669, approx. 1/8" thick. If you elect to sub a different pump you must use the correct thickness spacer for it from it's original installation.

Review Harolds 3A page Fuel Pump Article:
http://www.cj-3a.com/Fuel%20Pumps.htm

I'm reviving this tread, beacuse I wanted to get a spare pump to use in a tight situation.
I ask NAPA to cross these numbers, but they failed to cross. And there info doesn't go back past the sixties.

Anone have any new numbers that will work?

Post by **wesk** » Fri Oct 14, 2011 12:10 pm

The 60's is far enough back. The 1960 thru 1968 CJ3B pump is a dual vac/fuel pump that will work and the only difference is it's plumbing uses nipples for the vacuum instead of threaded fittings.

The 1960 thru 1971 CJ5 with F134 fuel pumps will also work and will just be fuel only.

The 1960 thru 68 DJ2A pump is another candidate.

You need a counter person who can see past the keyboard!

Cacti_Ken · Post by **Cacti_Ken** » Fri Oct 14, 2011 4:28 pm

I made a call to Autozone they are more close to me than the others.
Their computer showed for a 67 CJ5 a duel action pump by Airtex_Master #4032
max pressure range 5.5psi...min 4psi.

It has two metal tubes coming out of the vacuum pump. Has upgraded seals and laminated diaphrams to ensure compatibility with modern multi-fuel blends. I think I've seen this model on ebay sometimes.

RimfireJim · Post by **RimfireJim** » Fri Oct 14, 2011 5:51 pm

NAPA on-line shows the same Airtex 4032 listed for the CJ-3B, but it's not actually available from them on-line. "Call store for availability." It looks somewhat like the AC fuel pump an ebayer in Greece has been touting as an M38 pump (but looks different than the pumps I've seen in pictures on this forum), but there are a number of differences.

Post by **wesk** » Fri Oct 14, 2011 9:29 pm

This is the pump as illustrated in the CJ3B parts manual. No real difference other then the tubes for the vacuum half and the filter on top. It is used with a different spacer PN 647669.

Replacing fuel pump....stick w/ willys type w/ glass bowl or

Replacing fuel pump....stick w/ willys type w/ glass bowl or

WesK did all 3A's have the vacuum fuel pump??