1969 Chrysler 5 hp starts.. then sputters while running

Ive cleaned the carb twice, just put a new fuel pump kit on. I can get the motor to start but if I run it at low RPMs it will kick/sputter and then when I give it gas it hesitates/sputters until it reaches a higher RPM. Then it seems to run okay at the higher RPM. Also noticed the top cylinder where the spark plug goes in is very hot when running whereas the bottom is only warm..?? Not sure if that means anything but Im not sure what else to do.. any suggestions??? Ive also tried adjusting the idle screw.. it has a Tillotson MD carb which only has one adjusting screw.. as far as I know anyways.. still wont stop sputtering/hesitating..
?????
thanks

The carb: main jet has small holes in it.They control the low speed idle.They must be clear.The air screw:turn it out 1 and 1/8th turn,maybe more then start.Turn in till it starts to cough and sputter.Then out 1/2 turn.
Change the impeller if your worried about the temp.Just to be sure.
And run it in a BIG/DEEP bucket with LOTS of water.J

Thanks Jerry Ill try that adjustment..
I have another Q - would the motor run rough if I had the oil-fuel mixture to rich??.. I have been researching a bit and Ive read that Stihl 2 stroke oil is not a good oil to use and if you do use it you should use half the amount you would normally use of a regular marine 2 stroke oil. This is the oil that I'm using and I mixed it 50:1 so Im wondering if this is true?? has anyone else heard of this? Im going to change the oil and gas Im using and try another brand of marine 2 stroke oil to see if this works..

Update - I figured out I had a couple problems.. The 2 stroke oil I was using to mix with my gas was actually for air cooled motors not water cooled (which uses a different formula for cooling) and as soon as I switched to marine 2 stroke oil the motor ran better instantly. BUT it was still sputtering/hesitating at low RPM's and also when it was running the the top cylinder head was hot and the bottom head was cold which could only mean one thing. It wasnt firing/getting enough spark on the bottom cylinder. I decided to adjust the points (set the gap to .020) and try it. The motor started right away and was a totally different motor! Now revs with no hesitation or any sputtering.. it runs like its brand new!