A lot of people do not check there carb settings, it is easy to overlook if the truck already runs enough to drive it.
First I would get your owners manual and a couple of screw drivers, I would tighten your mixture screw all the way in counting the turns as you go, then return it to what it was at- Remember the number of turns- then look in the owners manual and compare to the base setting the manual prescribes. Maybe write on a note pad the number of turns you counted and try setting your carb to the setting prescribed by the owners manual, see how it does then. If it does not work, try adjusting until it will work, If it just doesn't run right return it back to the setting you found first so it will run.
That and looking at the conditions of your spark plugs will be your best indicator of running rich.
My 3100 was set way rich when I got it, and it just seemed sluggish when I drove it first- I adjusted the carb mixture and then checked the idle speed wit a dwell meter and now it runs like a top.
good luck
edited
scratch that I did not see the injected part, maybe try a hotter plug?
Last edited by Yelostn78; 01/02/2009 4:38 PM.
