Tiller bucks back and forth when lifted - King Kutter Ii Gear Driven Rotary Tiller 4ft

David try this there should be a piece of flat metal that is horizontal by the carb. bowl that you can push back and forth, it should have a hole in it. The end of that wire should go into that hole and you need to crimp that wire so that it stays in the hole attached to that piece I described that moves horizontally. Based by the picture of your tiller this wire is going control your throttle so that your tines turn.

Sounds like the tiller arm has a Kill switch in the end to shut the motor off. If it does there are two black and yellow wires in there and they are shorting to ground or to each other when the arm is lifted. This would shut the motor off when the are is lifted. The black and yellow wire is the kill wire on most outboards. If it grounds out and the engine will not run.

Yes, it is needed to set the depth of tilling, longer the bar is set the higher the tiller rides. The lower the bar is then the deeper the tiller tries to till.
The bar also helps you manoeuvre the tiller left and right. If you look at the owners manual you can see what it looks like and get one made if it is lost. It will work without the bar but it adds control when rotovating.
an example would be if the ground is hard or it finds some stones the tiller can buck about until breaks through the soil or it removes the stone from its path.
pushing down on the handlebars presses the bar into the soil, the bar lifts the tiller blades from the ground and it will settle down. Without the bar it wil buck until you pull it back away from the stones or into some softer ground and it can start munching into the soil again.

auto parts stores have a soaking tank for about 20 bucks

you need grease on your power shaft that has the forward/reverse this is where the power goes to the wheels slids back and forth A round wheel one side forward the other side reverse

try rolling it a bit. Sometimes the gear doesn't fully mesh correctly. As you try to shift push or pull the tiller juuuust a bit back and forth and try to shift as you do that see what happens. Or go into neutral and rock it then try again.

There are several possibilities:
1. the belt is old and over stretched and needs to be replaced.
2. you have a bent shaft that causes the pulley to speen crooked.
3. The pulleys are not lined up. You should be able to adjust them by loosening them and sliding them back and forth on the shaft.

The tines pull the tiller as you hold back. This is the way it supposed to be. 1973 model, It is not self propelled.

see if the motor turns over pull the spark plug put some lubricant inhole other wise pull off pull cord assembly try turning crank becarfull not tobreak rings moveback and forth little bit at atime if it turns over check pull cord out