The higher the nitro the colder the plug. The carb position with the barrel slightly open will be rich and as it opens more it will start to clean itself out until it screams, when going from idle to wide open, it should stumble a bit before it screams. If it goes from idle and sreams it will be too lean and can hurt the motor. Its better to be rich and get it launched then start to lean. Pipes and props also play a big part in this too. It use to be said long and lean or short and fat, it's all a trade off.
Brad
The medium heat range plugs will serve you well on 30, 40, 50, 60% and even 70% nitro. Novarossi #6 or McCoy #9 or K&B HP.
In the Buggy engine .024" head clearance is normal and works well. That won't work at all in the boat. About .010" will be a good starting point. Could go tighter for more power.
Once the low speed needle is removed from the carb, the carb opening will have to be set about 1/3 open for your IDLE position. You will want the engine to sound VERY rich with this setting. As Brad mentioned, it will get leaner as you open the throttle.
Do not try to snap the throttle open quickly or rev it up and down quickly while the boat is on the beach with no load on it. It won't take the fuel and could flame out. Just hold a steady throttle setting or slowly open the throttle to clear the engine. Once the boat is in the water and there is a load on the engine, the mixture will clean up in the low rpm range and throttle response will be great
There are plenty of prop gurus that will suggest the "latest greatest go fast" props. You just want to make successful laps around the lake to start with, so I would suggest an Octura X445 for the 40% nitro. I have seen the stock Octura X648 run very fast on the JAE with 60% nitro.They will hook up well on the JAE.
Keep your pipe on the long side to start with also. Maybe about 4" from the side/center of the cylinder to the high point. You can shorten it after you get consistent runs and begin to get more power from increased nitro.
