IS 14psi NORMAL FOR A STOCK FUEL PUMP ?

no, because I haven't done anything on the car worth keeping track of since the last entry

I'm getting very close to starting on it again, I've been working on everything but my car and have had some motivational issues

also my garage was a disaster, and I couldn't find my tools or the car, but I got that mess all cleaned up now

I hope to have something worth posting in next few days


Register now (free) or login to remove ads

The hole in the fuel pump case is not a vent per say. It just vents teh back of the diaphragm.
If the vent to the tank was plugged it would have the opposite effect, low pressure on the gauge as it would not be able to draw fuel from the tank which could actually cause a vacuum in the tank. I have seen this before and have seen partially collapsed tanks due to this.
I would be willing to bet that the little regulator valve in the pump is stuck or the spring failed.
Mechanical fuel pumps are pretty simple.

__________________
Artificial Intelligence is no match for Natural Stupidity



Chet

That's what I figured. OK Chet, permission to roll eyes!

High temp/heat soak can cause the fuel pressure to increase between the pump and carb. You might try isolating the fuel line from the engine heat, but the line doesn't look to be too close to the engine to begin with.

Yesterday was beautiful here, 64 degrees. So I put about 50 miles on the T-bucket. The new fuel pump is installed. While I was at it, I replaced the neoprene/rubber fuel line inside the stainless braid. The 3/8" fuel hose that was inside the braid was thinwall, and a good quality 3/8" hose wouldn't fit, so I used 5/16" which worked fine. Even though the fuel inlet needle and seat have less than 5,000 miles on them, they don't always seat. Every once in a while I can watch the fuel pressure bleed down to zero after I shut off the engine. I was very careful when installing the new fuel hose to make sure that it does not contact the engine anywhere. It has at least a 1/2" clearance to anything.
The fuel pressure with the new pump pulsates from 5.25 to 7 psi.. So far so good, no flooding idling. And the times that the fuel inlet needle seals, there is no hot start problems. Here's a few photos of the new install, and a running fuel pressure (just over 7 psi), and an engine shutoff fuel pressure (5.25 psi) when the needle held. It could be that the old fuel pump running 14 psi damaged the viton seat in the needle. Thoughts ? Big Al

Attached Thumbnails

       

Thoughts?

I got a thought for you mister!!!!!










































Thats one good looking engine compartment!
Glad you got it worked out

Big, have you closely inspected the needle and especially down inside the seat for any roughness/burrs/defects that could cause the needle to hang in the seat? Is the inlet hole at the bottom free of any burrs or defects that might allow fuel leakage past it? This takes good light and (for me, anyways) magnification to really see.

Does the float fit the "D"-clip (that acts as the pivot for the float) tightly?

There were several different D-clips used. Does yours fit the entire slot that's provided for it, or is there excess room (something like 0.150"-0.200") at the end that will allow it to move laterally?

Does the curved top of the D-clip extend above the plane of the carb body w/the gasket in place so the boss cast inside the air horn compresses the D-clip slightly to hold the clip in position so it can't move or rock?

Is the float straight and level w/the D-clip in place (not crooked because the float arms were bent a little?

All these things are to be sure the float is in no way binding.

If all else fails, you know that tiny spring clip that snaps onto the needle and hangs onto the float cross bar? If you are using it, take it off. If you're NOT using it, put it on. I know that sounds stupid- but I've had problems that were solved both ways.

BTW, there's virtually no way having the fuel pressure high should have damaged the needle. I'm sure Ruggles would replace the needle and seat if there's a problem w/it.

Good luck.

Thanks for the suggestions Mark. I will pop the top on the carb. and check it all out with magnifying glass tomorrow. Supposed to be high 50's a couple of days this week, so I should be able to get out and ride some . BTW FWIW ... I went into the garage yesterday afternoon just to look, and the fuel pressure was on zero. IMHO The fuel pressure should have still been at the 5.25 psi that it had when I shut it off Friday. Big Al

Don't assume it is leaking into the carb, it could be slowly leaking back past the pump. S long as it isnt leaking into the carb it is not really a concern

__________________
Artificial Intelligence is no match for Natural Stupidity



Chet

Agreed, Personally have never come across a fuel system that will hold pressure from mechanical pump to carb for more than a couple hours with engine off, not saying it cant happen but nothing to worry about.

Don't assume it is leaking into the carb, it could be slowly leaking back past the pump. S long as it isnt leaking into the carb it is not really a concern. [/QUOTE]

Thanks guys. Keeping that in mind. I will just give it a chance to prove itself, and see what happens before I tear into anything.