I am not shure

[7mJDM]

I am not a new welder but have not practiced much since high school I have a airconditioning shop and recently took on some welding jobs with my little crackerbox welder and enjoyed it and want to invest in a lincon sa 200, 250 or 300 and would like any advise or help I can get I have found one and am told it might be a little old maybe a 40 modle it is crank start and has a vacume run exciter my brother thinks we can take off and just fab a lever for like my dads little miller to weld or idle heelp