CKRC Forums

I've noticed in the last couple of test and tune sessions that I have an engine misfire or hesitation coming out of several corners. Could I be needing to make a float adjustment or needle adjustment? Could the mixture be a little too lean? Or rich? Any pointers would be appreciated. Thanks Ernie.

Are you hitting the rev-limiter (~6100 RPM) ?

If so, that's supposed to happen. If it's just for a second or so at a couple of spots right before you nail the binders, you're geared perfectly. Just feather the throttle a tad when you hit the limiter.

Otherwise, drop a tooth on your rear sprocket and you'll lose a few hundred RPM and come off the limiter.

Yes I am hitting the rev-limiter but only on the longest straight way. ( At about the start line, cw direction).

The sputter and hesitation is occurring coming out of corner 7 and 11 as I'm accelerating into the climb up to corners 8 and 12.

Of course I do acknowledge that weighing in well over the Briggs Sr. Heavy weight minimum does come with it's disadvantages!

Thanks for the tips!

Hi Ernie,

The floats do go out of adjustment over time. 22mm is the optimum float height from the deck to the top of the float with the carb upside down. You also want to make sure that the little pilot jets are also not plugged with a speck of dirt. Always run a fuel filter and replace it once a season.

Here is the tuning guide pdf. http://www.briggsandstratton.com/engine ... .pdf?la=en

Here is another guide: http://www.blastkarting.com/4-stroke-carb-tuning/

John K

Thanks John. I will check it out.

I had set my float, or so I though. But, as soon as I fired it up, it spit fuel out the overflow. There was a single grain of sand in the float needle slide bore. Have always been told, all it takes is a single grain of sand, but have never actually seen it happen.