2 + 2

[taz]

1989 100 hp, oil injector removed. Motor will start and idle. It will spool up to about 4000 rpm then die. while running at any rpm setting closing either throat of the upper two carbs kills the engine. Closing the throat of either or both of the bottom two carbs does nothing. The motor seems to be running on two cylinders. Any help would be appreciated.

The following has been done:
carbs rebuilt
fuel pump rebuilt
compression 120-125 all cylinders
new filters (GLASS full during operation)
new hoses
bulb (pumps up hard)

Can anyone explain how the 2+2 deal works and could this be causing the problem???

[boats.net]

Check that have spark on all cylinders.