CG-DC

I recently purchased a Pawnee and it has a Magnum XL .91 fourstroke on it. I got it running and it has quite a few leaks on it so Ive decided to do a rebuild. Im new to the glow engines and airplanes so some advice/assistance would be greatly appreciated. Where can i find parts for the engine? Im wanting to clean it up and replace the valve springs, Ive removed valve springs in small gas engines so i understand the concept, but cant seem to get the retainer disc off the top. any help is appreciated!

flybyjohn

My Feedback: (2)

You will need to hold the valve up tight in the head against the seat and at the same time push down on the ring on top the spring. When you do this it will allow access to the valve spring retaining clips which look like a tapered sleeve cut in half. These will come out and then the spring holder will slip off the valve stem. if you are not carefull the spring and top will fly across the room. Sometimes the retainers get stuck to the ring on top of the spring and it takes a little work to free it up. Be carfull not to bend the valve stems. If I were rebuilding more than one four stroke every 2-3 years, I would make a tool to take them apart.

If you haven't run this engine yet, it might be a good idea to just clean it up and run it to see if you even need to take the head apart. The valves might seat and seal just fine the way it is now.

CG-DC

Thanks.  i know the engine runs. just leaks like a siv.    its dirty and ive had a problem with the screw that secures the rocker arm.  the springs have gotten stuck and kept the engine from building compression.