Occasional stumble, every few months or so

[Amskeptic]

Update?
Did we talk about fuel pump guides freezing the pushrod when the engine gets hot?
Colin

We did not. But I'll take that into account if/when the problem recurs.

It is a "thing." With engine oil, push rod should slip through a removed fuel pump spacer. Do a cross-hatch on the push rod to help hold oil. Good VW bakelite/phenolic seems to do a better job of not expanding and grabbing the pushrod enough to limit the re-stroke of the pump diaphragm. The ony indicator here is that it is a "soft" fuel failure type of lurch, not an ignition "pow-dead-oh-we're-back" sort of jolt.
Colin

[JLT]

It is a "thing." With engine oil, push rod should slip through a removed fuel pump spacer. Do a cross-hatch on the push rod to help hold oil.

Not sure what you mean by "do a cross-hatch." Does this mean cutting grooves with a file, or using sandpaper to score the surface?

I'll be going to Buses By the Bridge, and the 600 mile road test will give me a good test of the new/old distributor-carburetor match-up. If the problem recurs, I'll do the push-rod thing and see if that helps.

Thanks for still paying attention to this.

[Amskeptic]

It is a "thing." With engine oil, push rod should slip through a removed fuel pump spacer. Do a cross-hatch on the push rod to help hold oil.

Not sure what you mean by "do a cross-hatch." Does this mean cutting grooves with a file, or using sandpaper to score the surface?

I'll be going to Buses By the Bridge, and the 600 mile road test will give me a good test of the new/old distributor-carburetor match-up. If the problem recurs, I'll do the push-rod thing and see if that helps.

Thanks for still paying attention to this.

Cross-hatch as in the 220 grit sandpaper with directional sanding. Do it before you are on the road. It is a half-hour job, stick on some fresh gaskets, check pushrod protrusion and stroke as per Bentley. Is your pump German Pierburg or Brazilian? A long journey can expand the Brazilian pumps without circlips holding the pivot pin. They sometimes like to drill themselves out of the pump body and leave you stranded ... like my customer in Jacksonville Fl on his wedding day.