I have a 98 magnum425 2x4 with a bad staling problem.

If you give it the gas past 1/4 throttle it stales, it
will eventually clear out but very frustrating. At full
thottle it will only go about 39 mph, should go at least
50mph. If I try to climb a hill with 30 degree encline
it just almost dies. When it is cold or cooled down
it runs pretty good until it warms up

I have had the carb apart and cleaned twice and can't
find any problems. The sparks plug looks like its running
a little on the side.

Any suggestions.

Thanks

 

I don't know much about carbs, but did you check to see if any of your jets are clogged or damaged?