Well Richard, there are certainly less expensive ways of trouble shooting
than replacing the carb to see what happens.

Problems with gasoline engines seem to be either of three basic things:

Air flow,

Fuel flow, or

Ignition problems.

Insufficient air flow is rare on boats but can happen. Check your spark
arrestor and clean it while you're at it.

Make sure your choke is fully opening once the engine is warm. Before doing
this check test your thermostat to ensure it allows the engine to warm
properly.

Have no idea what kind of ignition system you are using. Ensure it is
operating properly and that timing is correct. If it has been a while
change your plugs. Make sure your plug wires are in good condition.

Good luck.

Butch
"richard" wrote in message
...
454 mercruiser when running or idling it's getting gas in exhaust behind
boat
changed carburetor and still the same. Any comments will be appreciated