They won't open up unless the engine is under load. You won't be able to get the vacuum low enough without doing some damage to your engine. If you are suspecting that they aren't opening, you will need to do an on the water test with the engine cover open or off to see.
REBUILDING HOLLEY MARINE 4160 CARBURETORS - $199 DELIVERED
GENUINE MARINE HOLLEY KIT USED - INCLUDES POWER VALVE UPDATE
LED TRAILER LIGHTS, LUG NUTS SPARE TIRE CARRIERS, SAFETY CABLES....
Originally Posted by Bouyhead
Installed my carb that was rebuilt by thatsmrmastsercraft, Thanks Peter!! Hot or cold this boat starts and runs like it fuel injected.