Boat seems held back and i smell exhaust?

Question

had the carb replaced and it had a gas leak and a vaccume leak. the boat idles better now that the carb was rebuilt, but the throttle still requires you to be heavy handed to get going and when you ease off the throttle too fast , it stalls out, and at low speed it smells like im sitting on the back of the bus with exhaust finding its way inside till i get bus sick and puke on my homework. i almost think the exhaust is pluged up, but the boat can go 50 mph which is right for a 18 foot stingray. the engine is a 96, 3.0 mercruiser with a stock 2barrel

Answer 1

i would check floats for sticking or check fuel/air mixtures

Answer 2

What do you mean by heavy handed?

Is the cable heavy to handle or the throttle link on the carb itselve?

Replace the cable!

Sounds like the idle mix is set to ritch at idle.

Turn the idle s***w complete in till it bottoms out, then back off 1.1/2 revolution.

Start the engine with the throttle cable removed from the carb-side.

Now first set the fast idle s***w (throttle linkage stop s***w) so that the engine keeps running @ idle.

Turn the idle s***w until you reach the point of highest rpm or (highest vacuum) , re-set the fast idle and set engine rpm @ 750/800 rpm and repeat the above.

Good luck,

Frank

Answer 3

rich exhaust means too much gas, not enough air. Is there an air filter and has it been replaced? Is the inlet blocked?

I am not sure if the carb was rebuilt or replaced. A new carb may need adjustment, a rebuilt may have been rebuilt wrong. I don't know your carb, but a sticking or mis adjusted float/needle valve would run rich. you might also check the choke is open all the way.

Answer 4

Hope you got a manual with the new carb, it needs to be calibrated with the engine.   ie the idle speed s***w and rich/lean s***w need to be adjusted.

Furthermore, are you using the correct oil to gas ratio for that engine?