Painting both mechanical fuel pumps today from my BBCs and noticed one has a spring under the pump lever and one does not. I thought they all had the spring. Looked high and low but could not find a spring that had fallen out of the pump. Looking closely at the pump I can see a reciever for a spring, just no spring there. Actuated the pump by hand and it returned and seemed to work fine. Is this spring missing a problem?

BT

Could be.
I believe that spring keeps the arm in contact with the cam at RPM so it doesn't float like a valve with a weak spring. If I remember right that spring puts a lot of upward force. Very hard to move the arm by hand.
Have you had any trouble with that engine, fuel wise?
I'd be looking for another pump if I was you.

Both engines were running fine Iggy. Don't have pressure guages, so not sure if it was holding at WOT. Did have an exhaust valve failure on Memorial Day last year that I never did totally understand. I was at 4500rpm when it let go. Wonder if maybe fuel pressure was low and caused a lean condition up high.

BT

What'd you do, burn a valve?
Is that the motor the pump is off of?
It's a possibility that it's the cause.
At least you have the winter to find another one.

Yes it was from that engine. Valve stem really didn't show much in the way of heat and the rest of the valves looked fine. I better make it right now so I can rest easy. Makes me wonder where the little bugger (spring) got to though.

BT

the spring really has no where to go so my bet is it was not in place before it was installed on the engine.