Get That Engine Started!

Prime Your Engine
There are a couple of ways to prime your engine prior to starting.

The first way is to open the carb barrel to fully open, and then put your finger over the inlet. Next, turn the prop slowly anticlockwise (the usual way the prop turns). Watch the fuel come up the fuel pipe, and then, just before the fuel is sucked back down the pipe, release your finger. This will ensure that the fuel enters the carb and doesn't return to the fuel tank. Do this a couple or three times. Then start the engine in the usual manner. Make sure that you don't get a hydraulic lock.

The second way is to use a priming bottle. This is a small bottle with a little nozzle on the end. (Available at most model shops). Put some fuel in the bottle. Then as before, open up the carb barrel and squirt some fuel into the carb. Turn the engine over slowly, to ensure that you haven't got a hydraulic lock (due to too much fuel). Then give the engine a couple of good flicks with your finger, before engaging the glow clip. Then starting in the usual way.

If you do get too much fuel in the engine, turn the model so that the exhaust port is facing down and turn the engine over slowly by hand. The excess fuel will run out through the exhaust pipe. If the hydraulic lock is too severe and you can't turn the engine over at all, do not force it or put an electric starter on it. This will bend the con rod. You'll have to remove the glow plug to release the fuel from the top of the piston.

Engines vary in the amount of priming required. Some require more than others. You just have try it and see. Engine that have been laid up for a while sometimes need a good squirt of fuel in then just to loosen up all the congealed oil. A little bit of fuel will help in this case.

However, be warned that a hydraulic lock can occur quiet easily, so only put an electric starter on the engine when you are confident that the engine will turn over freely.