A friend of mine recently gave me a Piper Cub. It was given to him some years back and he never flew it. I know it has just been sitting for at least 5 years. I would like to inspect and clean the motor before I try to start it. How do I know what size motor this is? It is an OS Max FX motor. The wing span is about 76" if that helps. I have only been flying electric for the past couple years.

Thanks
Tom

A 76" wing suggests a 40 to 46 engine.

DaveB

I would agree with Dave it is likely a .46FX. If you have never operated a glow engine get experianced help.

Do not get to carried away on the cleaning the engine bit either. Is the engine frozen? is the carburator throttle barrel locked up?

John

If it turns smoothly just pull the needles and carb and install new o rings, then put some fuel in and turn the crank back and forth to work it into the bearings. Then start it and fly it. It may need a new glow plug, but there's no reason to replace it before you see.

It sounds like a Goldberg Anniversary Edition Cub. If this is the case, the 46FX is the likely engine, and a great match for the airframe. Run a few tanks through it before flying it. If it has been sitting around for a while, there may be dirt, etc, inside. A good starting point for cleaning would be the carb. If it is open, and you can visibly see dirt inside, chances are that there is dirt inside the engine as well. Don't turn the prop over, as it may grind dirt along the cylinder liner. I always find the hardest part is re-assembling everything, so photos can be helpful! <div>
</div><div>Graeme</div>

Thanks for the info guys,
John: The motor turns over freely and the carb opens and close's freely. The carb looks like it is clean.
Tom

Look directly below where the exhaust exits the engine block. There should be a number on that side of the engine case that will tell you the size of the engine. It is very common for people to put larger engines in those cubs as there is plenty of room for them. And pictures typically get quick answers.