84 kenworth bc350

I thought the pump timing was very critical ?
Or am I thinking of the pump on a Volkswagen tdi ?

How are you timing the pump when you install it ?

 

Big Cam Cummins doesn’t have a timed pump. Doesn’t matter what position the shaft is in when you install it…..

 

The old two strokes were a bugger to get primed. We had a primer pump off of a reefer engine that we would plumb into them to keep pushing fuel until they fired.

 

I always just filled the filter with automatic transmission fluid and restarted the engine , but I didn’t totally lose prime and have a system full of air

if your mechanic can’t get it running you need a more experienced mechanic to come look at it

 

You should be able to get it primed with nothing more than filling the filter unless there’s a vacuum leak or restriction in the supply side or possibly in the pump itself. The early pumps were bad about leaking air around the tach drive but wouldn’t leak fuel.
Did you try priming it like I suggested?
Just FYI 28psi will make that truck start and run especially with a little help from either.
It takes about 2-3 psi to make one run low idle with no load and maybe 5-7psi for high idle no load. 28 will make it run down the road but its going to be a pig
I would not expect to be able to stop the fuel with your finger. I don’t know about the small fountain thing.