Took the motor out of my chainsaw today. Is it worth messing with? The carb is on the bottom. Are there any mods for this? Not sure on how to hook the carb up to it.

These are great old engines.
They start and run very well.
If it ran good as a saw then it will run well as a conversion engine.
Saw motors to me make the best conversions anyway.
I have a Echo CS-300 that is of simular design I'm putting on an 120 ultra stick.

As with any conversion it depends on what your going to put it on.

You need to find the weight on the engine then look for a plane that calls for an engine of simular weight.
WWI and WWII planes need a lot of weight up front. Those stacked radial engines were vry heavy.
That's why the short even stubby noses on the planes.

What is the engine weight? And what was the bar size of the saw?

I'm not sure on the weight of it yet. I'll have to weigh it. It was on a 16" bar. Do you have any recomidations on how i should mount the carb on it?

I was given a small Homelite saw...like in new condition. I cut everything off that was not needed. I run the little devil and it screams!! The only thing it does not seem to have ball bearings on crank and the end play shows up when running. The business end seems to float around a lot. That one may go bye bye...real cheap! Capt.,[X(]

There are a couple of different materials that are used to make manifolds with.

The easiest one to find is the white cutting board material.

It's not real clear in the pictures how the rubber manifold is hooked to the case.

The reed valve must be under the rubber manifold.
And there apears to be a couple of screws holding it in place.

You will need to make a manifold that attaches to those screws that will hold the reed in place and
allow you to mount the carb while lineing up with your throttle linkage.

I did one of these 330's and put it in my sons BT-13. It turns a 22x10 prop 6800 rpm, lots of power. Making the intake manifold was a bear though. I used a piece of phenolic and kept carving till I got it right. That and alot of engine crankcase to cut off. Hope you have access to a good metal cutting vertical bandsaw! Heres some pics below:

Looks good.

A picture is worth a 1000 words .... maybe more.

Well i kind of figured that i was going to have to make my own intake. Thanks a lot for the pics. They definatly help.

One thing i did notice is 2 breather vents on the crank. Do i need to plug those? Also the carb has 2 inlets for fuel line?

It you probably be better if you used an external pulse for the Carb.
They work better and you won't have to worry about the pulse hole manifold for the Carb.
Then just block off the other one.

You probably had a bulb on your saw; the other "inlet" is a fuel return line.

The big fat yellow line is fuel in
Amber line is the pulse line. It simply runs into the manifold between the Carb. and the engine.
The blue line hooks to the bellows on the other side of the Carb, and goes into the dead air space.
This is so that air rushing by will not affect the Carb.