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MGB MGB fuel pump issue

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mmotors

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I have a 1964 MGB that had a original SU fuel pump that worked fine for years after I cleaned up the points. I did leak very slightly so I decided to replace the stiff diaphram and points with new parts. I set the points as per the manuel and unscrewed the diaphram until it just flipped over and then one more turn. Seemed to work fine at first, but stops at times and leaves me sit. Let the car sit for a half hour or so and it runs again. I tested with the pump out of the car and can get it to stop by placing my finger over the suction inlet. I can even remove my finger and it still wont pump until I shake or hit it. Any ideas why??? Thanks
 
:lol:

Dave will get ya up and running.

As a hint, just crank the diaphragm screw down another few turns.

...or just go with a ~better~ pump from Dave. :wink:
 
I have the same issues, and am looking to try something else in my car. Has anyone any experience with a Carter p60504 inline pump? I've a lot of bad stuff about Facet pumps, and I am not going for original appearance or sound, so would consider just about any affordable electric add-on that will provide reliable service.

Tim
 
The correct procedure is in the shop manual . Fit the rollers , screw in the armature in until the throwover ceases. Screw it back a sixth of a turn until "throwover " occurs . Then "two thirds of a turn" out. Make sure the points are centered. You haven't adjusted it properly. The Facet pump ( $45 at NAPA) works best mounted on an MGB rear gearbox mount Moss # 413-050 for noise, and pointed slightly uphill as it works best to push fuel. Its a good pump too and will run quietly with the gearbox mount and not produce too much pressure which can be a problem with aftermarket pumps. Kevin
 
I found that the diaphram rod was bent a bit and I straightened it. That may have caused the pump to stop? I also noticed that the new points were pitted a bit and suprised that it would have done that with only about 40 or so miles. I didn't replace the condenser- could that be bad? Or do they not work at all when the condenser goes bad?
Thanks, Shawn
 
Shawn - The capacitor (condenser) going bad will not stop the pump, but it will compromise the arc suppression circuit, which in turn will cause the points to burn prematurely. I agree with Kevin, it sounds like the adjustment are not set correctly, but you could also have other problems with a pump that old. It is hard to asses the problem without seeing the pump.
Cheers,
 
IMO the condensor was already tested... burnt points indicate it failed.

Tim_Creger said:
I have the same issues, and am looking to try something else in my car. Has anyone any experience with a Carter p60504 inline pump? I've a lot of bad stuff about Facet pumps, and I am not going for original appearance or sound, so would consider just about any affordable electric add-on that will provide reliable service.
Click to expand...

The low pressure Facet has been a great replacement in many cars here, the Carter P60504 as well. I've the Carter in my personal Alfa, supplying two 40 DCOE's and a Facet in the MGB (been there for YEARS) running SU's first and now a 40 DCOE. No problem with either.
 
So far so good. It has been running well since I straighten the diaphram rod, cleaned up the points with some sandpaper, and when I reassembled the pump I pulled the diaphram upward by holding it up with a screwdriver as a spacer (some suggest not to do this). I didn't do that the first time.
Weird thing is, now it ticks all the time (maybe one tick per second). It never seems to get to the pressured point where it stops. Any thoughts why (no it isn't pouring fuel on the floor)?


What is normal burning on the points?
 
"now it ticks all the time"
Could well be a bad check valve, either inlet or outlet valve. It could also be caused by an air leak on the inlet side of the pump (anywhere from the pickup tube in the tank, the fuel line from the tank to the pump, or in the pump itself). Disconnect the fuel line at the carburetor and direct the line into a jar, marked at the 1 pint level. Depending on what model of pump you have, you should get 1 pint of fuel in either slightly under 1 minute for the early pump, or 1 pint in just under 30 seconds for the later pump. The stream of fuel should not have any bubbles in it.
Cheers,
 
I'll have to check the valves. I noticed the valves have a smooth and rougher side- perhaps I switched them around? Which way should they go?
Ever put in a Transient Voltage Suppresser in place of the condenser? If so could it be purchased at Radio shack?
 
Shawn - The smooth side of the disk goes against the valve seat. You might want to lap the smooth side of the valve disks on some 600 grit sandpaper on a piece of smooth steel or glass to get any grove out of it.

It is doubtful that TVSs are available at Radio Shack, there are several hundred different voltage and power values for TVSs. You need on that has a maximum voltage cutoff of around 30 - 40 volts.
Cheers,
 
Thank you for all of your help. I will clean them up. The valve works as a check valve right? Allows fuel to go to the outlet line and keeps it from running back? So the smooth sides would both be facing the same direction inward toward the pump?
 
mmotors said:
Found this article: https://www.chesapeakechaptermgtclub.com/documents/FuelPumpTuneUp.htm

Can this diode be used in a MGB fuel pump? I see moss only sell a diode- could it be the same one?
Click to expand...

That diode listed in the Chesapeake MGT Club will work, although it will slow the pump down somewhat.

I see the diode shown in Moss but not listed in their price list and you could need a different end cover if you were to use that.

e-mail me at SUfuelpumps@donobi.net
Cheers,
 
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