Merc 9.9 ('89) Stalls at idle or low throttle

Motor has been in the shop 4 times for this problem. Is returned running fine. Within a month old problem surfaces. Engine starts fine and runs at mid to full throttle. After some time the engine will stall after running at idle. Choke and engine starts, but then stalls. Choke and engine starts, give it lots of gas and engine runs fine. Retune to idel, or low throttle, and engine stalls. Seems it is starved for gas.

Re: Merc 9.9 ('89) Stalls at idle or low throttle

What did the shop do? Did they rebuild the carb? Check timing advance? A little more info will help. Welcome and let us know some history on the problem...

Re: Merc 9.9 ('89) Stalls at idle or low throttle

Rick, what I recall is following:<br />1st - adjusted carb<br />2nd - cleaned jets<br />3rd - new spark plugs (ran great - adjustments)<br />4th - adjust carb<br />5th - disassembed carb. all clean and no varnish, did find very fine sand in needle valve. cleaned and ran for about a month. <br /><br />I called several companys about just buying a new carb. Spoke with a man in Idaho that said these carbs are nearly impossible to fix correctly. They do not rebuild, just replace.<br /><br />Seems to me the float might be the problem.<br />Each time the motor is hauled and checked it<br />seems to work ok for a while. Read several peoples comments about tapping the side of the carb with handle of screw driver to free up float. <br /><br />Thoughts???

Re: Merc 9.9 ('89) Stalls at idle or low throttle

Sounds like your strainers might be missing.<br /><br />Add an automotive inline fuel filter to your system.<br /><br />Yes, tapping the float bowl helps sometimes with a stuck float, but won't move debris under the needle.<br /><br />Also check your floats for fuel saturation. Take them out and float them in some fuel. They must all float at the same height.

Re: Merc 9.9 ('89) Stalls at idle or low throttle

Will try. Thank you for suggestions.