That reminds me of a friend that recently helped his brother with a no start issue.  It turned out to be the ignition switch.  Not sure about an intermittent problem like this, but it certainly has been the cause of many mystery issues. 

Eric Caron 

> On Dec 15, 2024, at 12:05 PM, Mark McCulley <mark@MARKMCCULLEY.COM> wrote:
> 
> The tach going to zero is a good clue that the problem is electrical. Problem could be the ignition switch of the hall sensor on the distributor.
> 
> -Mark
> 
>> On Dec 14, 2024, at 8:45 PM, Markus Benne <mbenne@m-bass.com> wrote:
>> 
>> It is possible, but it is a syncro and I cleaned the tank and filter about 2yrs ago, and replaced the fuel filter at the same time.
>>  It does actually feel like fuel starvation, or water in the tank.   Doubt it is water across so many fill-ups tho.
>> 
>> On Sat, Dec 14, 2024 at 11:17 p.m., Richard Koerner<rjkinpb@sbcglobal.net> wrote:   Most probable issue is clogged outlet from Fuel Tank.  Oh yes, it will eventually happen.  Most often seen at higher elevations or hot ambient temperatures, but summertime is just right.  This is a very common problem, after 40 years.  There is no cure, but is a cheap fix to replace gas tank.  You will need to do it sooner or later anyhow.  Of course at same time, replace the crossover tube, and every gasket and hose in the general vicinity.  Dennis was very instrumental on pointing out this problem area, and he was exactly correct.  Ken at VanAgain and GoWesty have some instructive videos about the whole situation.
>> 
>> 
>>