Hi to all boaters.

Went to Natal Endurance this past weekend which was great fun with some exciting racing and variable conditions. Unfortunately had one of my engines break a carburetor shaft on me which most probably cost me a place in that class, but hey thats racing! The shaft snapped in the middle where the screw clamps the butterfly and in the process the screw got sucked into the engine. Luckily no damage to the engine besides a small nick on the piston skirt which is still repairable. My question to all, has anyone had a similar problem and if so why would that happen and what could one do to prevent it from happening again. Was thinking of eliminating the screw and making a brass rivet to replace it as well as silver soldering the rivet to the butterfly and the shaft. All input would be greatly appreciated...

Thanx

First off ... generally shafts breaking are from a servo end point error that bottoms out stop at WOT, yet servo wants rotation to go further which twists shaft causing it to break.

** A few way to fix/keep it from happening ......

Set servo end point so carb at WOT is JUST at stop or just shy.
REMOVE stop from cast cover and set WOT position via servo end point.
Or ... look up Ron Buck and get one of his SS ( Stainless Steel ) Carb shafts.
Ron can be contacted here: This email address is being protected from spambots. You need JavaScript enabled to view it.
If a member of JRCBD ? Posting on shafts here: www.jrcbd.com/showthread.php?t=40601

Thanks for the reply Scott. Everything you have said is 100% true and that is exactly what I do and look out for? Also there is no sign of wear on the carb casting telling me that my EPA at WOT was correct. Could the resonate frequency at 19K - 20K rpm have anything to do with the breakage?

Thanks

Ron Buck's shafts are great.

Just take your time when replacing the old one to get the butterfly set just right and make sure you use locktite on the screw.

I have 4 of Ron's shafts .. great investment