1969 25 hp Sportster dies after running WOT

[69 Alumacraft]

So I ran it with bad gas and then drained the carb and got her going again except after I run it WOT and then slow down to idle it dies. It will start back up when I pull out the choke and runs fine and it runs well at WOT but always seems to die when I slow down to idle speed. I have been using this motor for 4 years and have rebuilt carb, new fuel pump, rebuilt ignition. My gut tells me it is related to the watery gas I put in her. I am thinking of draining the carb again. Any thoughts appreciated.

 

[Noltz]

Re: 1969 25 hp Sportster dies after running WOT

It's very likely due to water in the fuel system. Water won't atomize like gasoline. It's surface tension is higher. If this were a four stroke I'd say use a little gas line 'antifreeze', which is just alcohol. It will mix with gasoline and thin it out to let it get through the engine. I don't know what alcohol will do to a two stroke, so if it were me I'd pull the carb down and blow it out. If anyone else has had any luck with alcohol & two strokes I hope they'll post up.

In any event, bring the fuel to a garage and ask them to dispose of it. Start with fresh.

 

[69 Alumacraft]

Re: 1969 25 hp Sportster dies after running WOT

Yep. Drained the carb, fuel line and tank. Started with fresh gas and problem is gone. Engines don't run on water.