"richard" wrote in message
...
454 7.4 mercruiser when running or idling it's getting gas in exhaust
behind boat
changed carburetor and still the same. Any comments will be appreciated

Gas in the exhaust means one or more cylinders is not burning or is/are
running rich. Since you changed the carb you might assume it's not a carb
problem.

I'd run a compression check (wet and dry) to see if a cylinder is low on
compression and not firing.

I'd give it a tuneup (check the timing and ensure that carb is properly
adjusted) since this will give a good place to start. Make sure the choke
opens properly. When you check the timing, ensure all the plugs are firing
properly. Check the wires, plugs, cap, rotor, etc.

You did not say whether the motor runs smooth or rough.

Bring back the results.