Mercruiser 5.0 Excessive Fuel Consumption

[RabbleRouser]

I have a 1992 Mercruiser 305 Alpha One, Gen II installed in a 22 foot Glasstream boat that apparently has a carbueration problem. I mean this thing eats gas varaciously,(i.e. uses 20-25 gallons of gas in a 2-2 1/2 hour cruise time at 3000 rpm). The engine seems to flood during the first start of the day but eventually will start and will continue to start uneventfully the rest of the day and has plenty of power. Is this normal fuel consumption for this type of engine?? Its a V-8 with a 2 barrel Mercarb carbureator installed on it. If its not normal fuel consumption is there anything I can check externally on the carbureator such a the fuel/air mixture adjustment or maybe the choke? If not I'm open for any suggestions including a Carb rebuild. Thanks.

 

[corm]

Re: Mercruiser 5.0 Excessive Fuel Consumption

Hi RR,<br />At WOT (4400 RPM) you will burn around 20-22<br />Gal/Hr. At 3000 RPM it should be about 7.5-<br />10 Gal/Hr. <br />Things to do to maybe help; check plugs, ing<br />timming, use a good grade of fuel. Your carb<br />may need to be rebuilt,but 1st make sure the<br />choke is wide open as soon as the motor is warm. Only adjust the carb when motor is warm<br />and in F gear.(idle speed in gear 550-650RPM)<br />I like it towards the high side.<br />Every rig runs different depending on weight<br />and where it is placed,how clean the hull is, is it waxed (eek),where the trim is set,<br />also how much the hull weighs. I would do some tweaking on it cause of gas prices.

<br />If the stearn of the boat rides low in the water at 3000 RPM some trim tabs put on the transom would help lift it more to the top of the water and should help fuel usage.<br />...have fun...corm