O.S. RG .21 Nitro Engine Install in BMT 984 Onroad, super tight pinch

My Picco has issues staying running without the glow plug igniter. I got this in an ebay lot about a year ago. The guy said it was new and it looks new. The. The pinch is crazy tight. I'm going to run a couple of half tank heat cycles through it first.
Fuel I'm using for break in
https://www.amazon.com/gp/product/B096SJWC6L/ref=as_li_tl?ie=UTF8&tag=fintechcomm0f-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B096SJWC6L&linkId=5ba35b3ac2a6e4811cf43a92cdc8f3d1