90 hp yamaha stumbles and sputters after 10 to 20 sec

[arkboater79]

Just got a bass boat with a 90 hp yamaha prec. blend 2 stroke. Runs great for about 20 sec wide open then stumbles and runs rough, seems to run ok at low speed but as soon as you throttle up it starts cutting out. I changed plugs and put high test gas .If you let sit , it will open up but soon craps out. Thinking of changing fuel pump, but while it was acting up i pumped bubble with no change,slight choke no change. Any ideas?

 

[robert graham]

Re: 90 hp yamaha stumbles and sputters after 10 to 20 sec

Check fuel delivery from tank pick-up,tank vent, fittings, primer bulb, cowl quick disconnect, fuel pump, filter, lines, for air leaks, bad gaskets, seals, etc. Drain each carb onto clean white rag and look for signs of water, trash in carb float chambers. Then if all is well there you may need to have carbs cleaned.

 

[arkboater79]

Re: 90 hp yamaha stumbles and sputters after 10 to 20 sec

Thank you Mr. Graham. I will do just that. Much appreciation.