This is a wonderful site, I love it !
A couple of questions for you. I just got a Poulan, 36cc chainsaw, model 2150 and a Roybi 31cc weedeater, model 720r. Both turn over easily and have good compression. Looking into the exhaust port the pistons look smooth and clean, no scoreing.
Are either of these worth converting ? What kind of performance numbers are you getting from these ?

Both will make nice, and fairly easy to do conversions. The Ryobi will turn an 18 x 6 prop at around 7500 if you put a little larger carb on it and gut the muffler and provide a bigger outlet. The Poulan will be more powerful, but is a touch heavy. It uses the same basic block as the Poulan 42cc, and weighs about the same. But it is stll worth converting.

AV8TOR

P.S. Here is a pic of my Poulan 42cc when I was putting it on my Giant Stik. I forgot to mention that the Ryobi can be run either with the magneto or with electronic igntion, but the Poulan can only be run converted to electronic ignition because the magneto coil mounts to the saw, not to the engine.

Hello and welcome to RCU and especially the engine conversion forum.
Youll find all of us in here are a great help to one another and theres a lot of resources and hands on experience here as well.
Youve got a good start with those 2 engines.Do a little search and you find lots of info.
After you start youll find out 2 engines arnt enough,trust me on this.
After your first is running,youll need more.
Then youll need more tools,a lathe,drill press,ect...
Then youll need a work place or shop.
Then youll need more planes for your engines!
And it will go on,and on,and on,ect...
This is normal behavior for people in this forum.
Always pick up free engines and dont turn down any.
If you ever need an answer,where here or PM me.