Algodoo

The principal is leverage, you are asking the engine to do something it has not got enough power for. It would be like putting a car's engine from standstill into gear 5. Your engine stalls, what you need is to do either one or both of these things:

1. You MUST use gears to reduce the power needed for the pump jack. Or get a more powerful engine by increasing the weight of the cylinders or something.

2. You could use the principal used in cars of having a clutch so the engine doesn't have to pull the pump when it's starting. This would help your engine pick up speed for when you engage it. But, without the gears to reduce the power required it will just keep stalling.

Okay thanks well ill try to find a motor

use the engine used in my Opel Astra
it has alot of power
and still very small

Use one of my rotary spawn engines theyre really simple and produce tons of power. My first rotary spawn engine can pull a 10^7 brake without even slowing down (but thats at 240 Hz frequency). All of my rotary spawn engines are actually MORE powerful under load, so let them run slow and they will do the job for you

Rhett07 i am making the entire machine with one of my engines