by loucrane » Tue Aug 26, 2014 11:32 am
Wills,
Welcome back!
I had a Johnson Stunt Supreme back in the 1950's. That's a lot of engine for the little SIG D-7!
Glow plugs are the same standard size as they were way back when. If you have a hobby shop nearby, one that isn't totally gone over to electric power, they'll have glow plugs. You don't need any super-fancy, high priced plug. Most plugs now have an "idle bar" across the end of the opening for the hot coil. Your option...
MECOA sells the old standard K&B glow plugs, and at a great price compared to what you'd find in a bricks-and-mortar shop.
I don't remember what the original Johnson NVA (needle valve assembly) was but you may be able to find a suitable one here at MECOA. If not some of the other direct order houses could supply ENYA or OS NVA's. Best fit puts the fuel hole at the middle of the throat. If it is one hole, aim it just off straight down along the airflow direction. In fact, just out of sight as you look in draws fuel well.
If the spraybar has two holes, they are likely drilled a bit off the center height of the spraybar tube. These should be turned so they aren't visible from the opening...
Remember - that's an iron and steel engine. Newer engines are made of different metals, and set up to run on less total oil, of which more % is synthetic instead of castor. I'd recommend trying to find a fuel with at least 25% oil, and at least half and half synthetic and castor. Or add castor to an RC fuel. About 5 oz castor to a gallon will raise an 18% total oil fuel to a bit over 23% total.
Best of luck!