Has no power and uses alot of fuel

The best suspect would be a jumped timing chain, especially if the engine is also hard to start. The only model I found that is close is a 720. That one with a gas engine uses guide shoes and a spring-loaded tensioning device, so there's all kinds of things that can allow the chain to become loose. Even if it didn't jump a tooth, a loose chain will cause late valve timing. That will cause real good low-end torque to tear away from a stop sign, but reduced high-end torque that will make it hard to pull out and pass people when necessary. A good clue, if you haven't adjusted ignition timing, is it will be considerably retarded from specs. If you did adjust it and had to go quite a ways with the distributor to advance it back to specs, also suspect a stretched or loose timing chain.