I am making my rider mower into a go kart, Not switching the engine to a frame, but using the mower frame itself.

I plan on making my throttle the gas petal. But I want to elminate the tranmission. On go karts they are always in drive, press gas, you go, and press brake you stop. Can I take out the bars pulling on the tranmission and just use the throttle. Or when I turn on the engine will it start to move without me on it. If my throttle is all the way down, will the mower move if the tranmission is all the way up. Is there a way to make my engine be in drive when it gets turned on.

PLEASE HELP!!

If you remove the transmission you will have a direct drive which means that the wheels and the engine are locked together. When a small gas engine is running the output shaft is ALWAYS turning because it is actually part of the crankshaft. The only difference being the more throttle used the faster it turns. What this means is that you have to push it to start it and kill it to stop because even idling the output shaft is turning which means you are moving, albeit slowly, but you are moving.

What you need is a thing called a centrificul clutch. This is a device that bolts on the output shaft and has shoes on it similar to what drum brakes look like if you were to pull off the hub of a car. These shoes are held in place with springs. It also has a cover that covers it and has a sprocket on it. This sprocket connects to the wheel sprocket with a chain similar to the setup on a bicycle with the exception being the engine is driving the wheel not your legs. As you give the mower/cart the gas the clutch spins and centrifical force causes the shoes outward until they contact the cover. Once the shoes contact the cover it locks the 2 pieces together and then the whole assembly turns as one unit making the mower/cart move. When it is at idle there is not enough centrifical force to hold the shoes against the cover so it release it and you can stop with the engine running. This is of course "assuming" the small gas engine has the output shaft coming out of the side not the bottom. A centrifical clutch will run you about $30.

Couple things you may want to take note of though. Most riding mowers have the output shaft coming out of the bottom of the engine not the side (i.e. horizontal) whereas the axle shaft with the wheels and sprocket are vertical. The purpose of this transmission other then eliminating the clutch is to change the horizontal drive of the engine to vertical vertical drive of the wheels. Without the transmission then you would have to fabricate up sometype of a worm or pinion gear setup to change from horizontal to vertical which would not only be costly it would be unpractical.

Plus the frame of a riding mower is very heavy and the transmission is geared very low so even doing that would not make much of a go cart (as in slow and would handle so poorly that if it was going fast it would be extremely unsafe and scary). I did the same thing as a kid and wasted many days on this project only to find out that it in fact was a waste of time. I would save my allowance and look around for a used cart or cart frame and then invest the needed $50 or so for a used side shaft small gas engine that way although you will not have a race class go cart you will in fact have a go cart.

Youtube.com
How to convert vertical shaft engine to run horizontaly by kougsohv9, and
Vertical to horizontal 3-1/2 briggs by ChargerMiles007
I would leave the transmission on it and change pulleys for higher speed.
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