[Kartbuilding] Fwd: Kart building questions...

[Stephen Burke]

Hi Al,

There are two options to quiet down an engine:
#1 Fit a better exhaust of a different exhaust. You must make sure
however to have a proper gasket, otherwise it will be useless. You
could adapt an exhaust of a similar engine or motorbike.

#2 You can have a go at fixing the "Governor" which is mostly likely
the problem with your engine.
In typical engines, there are cooling fins attached to the rotor on
the crankshaft and also contains the magnets for the magneto. Use is
made of these cooling fins to operate a Fan Lever. When the engine is
going slow, there is little wind generated and as a result there is
less pressure on this Fan Lever. When the engine speeds up there is
more wind generated and as a result there is more force acting on this
Fan Lever.
Using this principle, a governor is usually obtained. A spring
connects this Fan Lever to the throttle/ butterfly valve on the
carburattor. When the engine is going slow, there is little pressure
on the Fan Lever and the throttle/ butterfly valve has little or no
pressure keeping closed.
When the engine speeds up and perhaps too excessively, there is more
wind generated, more pressure on the Fan Lever, and this pulls back on
the spring governing the throttle of the carburattor.

I hope you get the idea somewhat. If you look at the carburattor on a
similar engine or even a basic lawnmower engine, you may see this
principle. On modern engines and on generator engines, the governor is
built into the engine. Basically, if the engine goes too fast and
noisy, the throttle is cut back.

In relation to speeding up the tractor lawnmower here is what you must do:
Keep the 6 speed gearbox or current setup as on the tractor lawnmower.
It is best to leave this well enough alone.
What you must do is either to gear up before the power gets to this 6
speed gearbox or afterwards.

So:
#1 Connect up the 14 hp engine using the ribbed pulley wheels to the 6
speed gearbox. Use correct ratio pulleys to gear up the speed. I.e. a
large pulley wheel on the engine and a smaller one on the gearbox.

#2 After the transmission/ output shaft comes out of the gearbox,
using pulley wheels here, gear up the speed before reaching the
differential/ rear axle. Again a large pulley wheel on the output
shaft of the gearbox and a smaller one on the differential/ rear axle.

I hope this answers your questions.
Best of Luck
-steve

> TUE JAN 11th
>
> Stephen;
>
> I just found your Website and e-mail address on the Internet while looking
> for helpful information on how I can accomplish two things;
> 1) Quite down a Briggs & Stratton 14HP OHV engine and exhaust system, and
> 2) How I can change the speed (pulleys) from that of a 6-speed lawn tractor
> to that of an off-road vehicle? I would also like to go to ribbed pulleys
> and a wide belt.
>
> I have taken two old lawn tractors I have discarded and am building a little
> work and play vehicle for my hunting lease/camp and a utility trailer. It
> will consist of a converted lawn tractor with a 14HP Briggs and Stratton OHV
> gas engine and the front axle assembly from the older lawn tractor will be
> used to construct a 36" wide utility trailer for hauling feed to our food
> plots and deer to our hunt camp.
>
> Any suggestions?
>
> Thanks,
> Al Barrs