Thanks thats the plan. I only got to trying a new plug with the correct gap yesterday. I'm going to need to go back and check the whole ignition system and also go through carb again. It starts up right away but now it has no throttle response and just blubbers a while and then dies. I have checked to ensure the throttle is opening the slide correctly as well. 

Can you post a video? 

I will try to this afternoon

Here is how it is running currently with a new regapped spark plug. It goes without saying that I have some sorting of things to do. No responding to throttle at all and hardly running. It was running better the other day when I was able to get it to rev to 4000 rpm. As I said before going to go though the ignition system again and carb and see where that gets me.
youtube.com/shorts/3ReadoajVkY?si=CKDfKZ5Wd9S8SJhk

<iframe width="328" height="583" src="" title="August 31, 2023" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen>

Is that your condenser hanging by your spark plug if so it needs to be grounded 

Hmm, ok, doesn't sound like you're opening the throttle--or are you? & if so then limited by electrics-ignition.
If possible a good long vid of trying to rev it up would be great.
I withdraw my exhaust idea though at this stage.
What sort of open gap do you have on the points, are the way too wide at max gap.
In saying that, i've seen some points cam send them wider just before starting to close & not sure why or if the points cam wears unusually on some.
Theoreticaly points just breaking at 3.2mm btdc & should be good.
Sort of sounds like a bit of a misfire once during the short run, or its totally limited by the misfire.
I watched in for a while before realizing it just replays--learning curve for me haha thinking--hang about, its getting going--then its not, but its replaying.
Thanks for the video though.
Sorry keep editing hope it's readable.

Yes that is the condeser just hanging there. I haven't found its new home yet but it is grounded to the coils ground. Yes the throttle is being opened and closed while running. It is a short video because that is as long as it wanted to run yesterday. Definetely seems like it is misfiring. Points were opening at 3.2 btdc when I timed it the other day but I plan on checking that agian.

I felt sure HT1KID had solved it.
I hadn't noticed condenser hanging there.
Is the earth somehow attached to the body then to frame earth & the wire in to the coil wire in.
If it wasn't earthing i'd expect sparks to be visible jumping off the condenser body to any earth close by.
Playing it again & if for some reason the earth isn't earthing it looks like the nearest thing is the rubber plug cap so can't jump sparks.
Be good if you could look in at the points while someone keeps it running & see if they're arcing like a welder or just minor sparking.
Is there any chance you're lighting coil wire--one of them--has got involved with the black.
I did that once on purpose as a cheap fix as had a faulty source coil so used the lighting coil but put too much voltage into condenser & points so it arced & misfired very similar to yours.
So picked the lowest output & worked good--not sure for how long now as went back to the owner.
Had originally gone for the yellow highest output but was too much voltage & poor point just about welded together.
Source i think are wound to limit out on voltage where lighting voltage just keep climbing the higher the revs--i think!!.
That trick, good or bad was for someone with no money for a proper fix that i did on an AG100 which is just an LT2 based farm motor.

RT325 I didn’t see the body of the condenser grounded  he should ground the body and see I hope he will post some pictures of the wiring

Yeah he does say "I haven't found its new home yet but it is grounded to the coils ground." So should be ok. Mabe there's a mount around behind with a wire going to earth. Getting very interesting so hope a cure is found. Video makes all the difference doesn't it, & takes a lot of the guess work out of it.
Thanks for the video bhepp15.