912 run rough on climb or heavy load

"Fuel Related

Anyway so to hopefully eliminate the fuel delivery options I ran new fuel lines and as a test ran a new fuel line from the suction side of the fuel pump into a jerry can of fresh high octane fuel. no change."

I am confused - To test for tank to carburettor (p[en hose) fuel delivery, I would expect that, each carburettor fuel line would be disconnected  (one at a time), pointed into a suitable receptacle, the Boost/Auxiliary electric pump  turned on and the time taken to deliver a significant quantity of fuel noted. Fuel quantity/time = flow rate

Where a fuel pressure gauge installed - the pressure noted (it should be nil or close to it).

If flow below expected :

 # And pressure above zero- possible partial blockage/restriction.

 # Pressure zero - pump problem.

"I ran a primer to the fittings on the bottom of the carb and tried that."

What is "a primer"  and is "the fitting on the bottom of the carb" the float bowl fuel inlet??

Perhaps you could rephrase and/or send a photo.

😈