Spark Plug Question

Hello, all;
I just joined these forums so, please bear with my first post.
I have an older Simplicity snow blower with a Tecumseh (Model/Serial #) HS50 67201F SER 5168B
This blower was given to me by a friend like, 5 years ago with a bent auger blade, I repaired and worn-out height feet, I replaced.
My reason for this post, for whatever reason the primer isn't getting fuel to the carb when the engine is cold (I say when it's cold because, if I pump it while it's running, it causes the engine to slow down). SO, I have been removing the spark plug to put a few drops of gas in to get it running. It works for me. I'll get into it deeper in the spring. Anyway, I've noticed the tip and porcelain
of the plug are black, telling me it's running a bit rich. It runs fine, no matter how deep or thick the snow and it will sit and idle when I drop it down to idle.
My question is this, could I use a hotter plug or, is that asking for trouble? I am not sure of the plug in it now, I can provide that if needed.

Thanks for your reply, Scott. The plug currently in it is a Champion J8C but, who knows how old that is. Past experience tells me the "R" of the RJ8C denotes a Resister plug, which were used through the years to cut down ln radio interference. I did, however re-gap the plug to .030". It was a bit under. .025 was loose and .030 was too tight. This is assuming .030 is the correct gap. I am going to go to the Tecumseh site and see if specs for that engine are still available.

Well, I ended up having to get an NGK plug #B6S or, 93324. It crosses over to the J8C. My local supplier (Fleet Farm) didn't have either Champion plug. I can only hope it is as reliable as the old Champion has been.