ORIGINAL: ob nut

The "crank" pressure is normally used on throttle exhaust motors only. Don't think altering this would effect the needed pressure. Other things to consider:

1: Bearings - smooth? top bearing or even the pto's could be leaking.
2: Cracks in the cases?
3: Fuel tank keeping pressure? brass lines ok....
4: Water temp? if cold, remove water pickup.. The lower will act like a heat sink.
5: Check the flex cable / output shaft for any concerns.
6: Is the needle assembly clean?
7: Richen the fuel up. Motors normally don't die when running rich. Open 1/8 to 1/4 turn each time out. Starting point, as already stated early in thread, would be around 4 turns out.

Toss on a 1oz hopper tank. See if the fuel feeding process needs to be relooked at. At times the K&B won't keep running because the fuel is not high enough for the carb to draw on. As you can tell, they are many areas to look at for this condition.

Last year my SS motor would only run 3/4 throttle while it was opened up over 5 1/2 turns. Nothing much I did to it worked.. After sending the motor to Rod G., he found a issue with the crank case. I didn't see a thing. Motor runs great now.