stalling merc

[bones]

1971 merc 400/40hp starts and idles but when you give more throttle starts to run rough then shut off

 

[Walter]

Re: stalling merc

Most likely a fuel related problem. Check all the basics...make sure the fuel is new/clean/no water in it ect. Make certain fuel supply hose is clear...not pinched or restricted. Check any/all fuel filters...Geez, the list goes on. Have you tried pumping the primer bulb when the engine begins to hesitate and stall under a load? Try it...see if it helps it run. If so, then you know you aren't getting enough fuel. The problem might be with the carbs...or the fuel pump. 12 footer will say it might even be a ski rope wrapped around the prop! Hey, it could happen!<br /><br />Try these things...let us know what happens.<br /><br />Walt

 

[bones]

Re: stalling merc

tried new fuel, cleaned carb,rebuilt fuel pump. seems to run better if i keep constant pressure on fuel bulb <br /><br /> Thanks alot <br /> Nelson

 

[kevlar3000]

Re: stalling merc

Any air leaks in the fuel line? I would replace the bulb and the line if you did not do this the first time. Is it set to lean? They can stall out if that is the case. And finally did you replace the floats in the carbs, or just clean the carbs? Maybe one is sticking...<br /><br />Good luck