Agreed more info would be good. Your carb is old enough to have had the power valve ruptured from a backfire. Holley part #125-500 is an update for 1989 and older carbs. To test your power valve, while holding the large end, try to turn the small end. If it will turn, the valve is shot. If it won't turn, the valve still works. A blown power valve goes to full rich and the boat is barely drive-able, and will be leaving some black smoke.
Another possibility for running rich is a choke set too rich. Your choke should open fully within one minute of start-up.
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.