Gents, I need some help. I have a couple hours of seat time on my recently acquired '48 8N. My dad said it "misses" and has done so for years. He chased the problem with a carb rebuild kit in 2015 and a rebuild kit (3-8T-010?) performed by Norther KY tractor & equip in 1999. I'm not sure what kit that is but it looks like new dist wires were installed also.
I'm not sure that it's miss firing but I can describe the sound as an intermittent popping. Not loud like a backfire, but a soft puff at any RPM range. Could be a miss fire I suppose. The condition is worse when the choke is fully off. It runs smoother with the choke held out about 1/4 inch.
I was running a blade today and it started running worse than usual, sputtering and running really rough like it was going to stall. It would rev and sputter out repeatedly as the governor pulled and released on the carb linkage. It seemed to smooth out if I held the choke out even further! After trying to run it that way, it would run rough again so I'd push the choke back in to the original 1/4 inch out using clothing pins on the choke stem. I also screwed the final mixture screw out a little which seems to smooth things out, but not sure if that was the problem.
Strange thing is, it started running smooth again for reasons unknown. Smoother than I'd ever seen before without any of the popping or missing I previously described. Still with the choke held out 1/4 inch. HUH? How can it run like crap and then run perfect?
To top things off I parked it, shut if off, and then decided to park it elsewhere. DEAD BATTERY! In retrospect, I don't think the voltmeter increases/decreased with engine RPM. It only increases slightly when the ignition is switched on and stays there. Shouldn't it change with RPM's? Checked the belt, it's tight. The battery is a 2015. Connections all seem tight.
Another thing, there is no throttle response in the first 1/4 to 1/2 of the throttle quadrant. governor spring isn't really loose but isn't so stiff it can't be turned in the I also noticed it would pull back slightly from the end of the quadrant when running at wide open throttle. Any ideas? Thank you all in advance. I really want to get this thing purring like a kitten. I really like it and want to keep it alive for my grandpa, the original owner.