motor idling back then surging while throttled-up

[joeken]

I have a 1996 60 hp mercury outboard and it has begun to back down to an idle for about ten seconds while at full throttle then will go back to full throttle for about ten seconds and it continues to idle/surge, idle/surge as long as you have it at full throttle. Anyone have or had this problem and what is the solution?

 

[Georgesalmon]

Re: motor idling back then surging while throttled-up

Could be a dirty gas filter at the fuel pump or carbs. Try running while pumping the bulb abd see if you can keep it at full speed.

 

[joeken]

Re: motor idling back then surging while throttled-up

Could be a dirty gas filter at the fuel pump or carbs. Try running while pumping the bulb abd see if you can keep it at full speed.

tried this and does not help

 

[Texasmark]

Re: motor idling back then surging while throttled-up

Since you responded as you did, and your problem is at high rpms meaning that the high speed jets are supplying most of the fuel, I am going to bet you have a clogged/clogging high speed jet as I had. I would think that a clogged fuel filter would produce a constant power reduction as would a weak fuel pump.

Pull the bowl off the carbs and check for varnish. If you find some then clean the carbs with carb cleaner and compressed air.

If no varnish and if your carb is the same model as mine (VME-XX), looking in the bottom of the bowl is a cast alum cylinder that sticks straight up and mates to a gasket on the bottom of the carb proper. Embedded in the side of this cylinder is the high speed jet. Stick your compressed air nozzle in the cylinder and blast it thus forcing any foreign mater backwards out of the jet. If yours is like mine was you will dislodge a blob of crud and your problem should go away. I didn't have any new gaskets when I did mine so I ensured that I returned the bowl to it's respective carb hoping to match up the gasket deformation with the mating parts. It worked and I didn't need a new set of gaskets.

HTH,
Mark

 

[joeken]

Re: motor idling back then surging while throttled-up

Since you responded as you did, and your problem is at high rpms meaning that the high speed jets are supplying most of the fuel, I am going to bet you have a clogged/clogging high speed jet as I had. I would think that a clogged fuel filter would produce a constant power reduction as would a weak fuel pump.

Pull the bowl off the carbs and check for varnish. If you find some then clean the carbs with carb cleaner and compressed air.

If no varnish and if your carb is the same model as mine (VME-XX), looking in the bottom of the bowl is a cast alum cylinder that sticks straight up and mates to a gasket on the bottom of the carb proper. Embedded in the side of this cylinder is the high speed jet. Stick your compressed air nozzle in the cylinder and blast it thus forcing any foreign mater backwards out of the jet. If yours is like mine was you will dislodge a blob of crud and your problem should go away. I didn't have any new gaskets when I did mine so I ensured that I returned the bowl to it's respective carb hoping to match up the gasket deformation with the mating parts. It worked and I didn't need a new set of gaskets.

HTH,
Mark

thanks i will try this