I have a couple of older units in the garage.
My snow blower calls for a RJ8C plug. All I could find was a J8C Plug. All they the same plug? Did Champion just drop the "R" id?
The manuals I'm using are from the early 80's.

 

It's basically the same plug and using one is fine where the other is called for. The R just designates it as a resistor plug.

 

Thanks Cheese.
I just wanted to be sure of that.

 

Square Head,, can you recheck the plug number?? The "J8C" sounds like a pretty cold plug for a snowblower.... Any I see have an "RJ19" or an "RJ19LM" in them (most L-head brigs & tech) which is a hotter operating plug than the "J8C" for the cold temps a snowblower runs in... What engine are you running??? Roger

 

It's a Tecumseh HM 80 8hp.
My manual claims it's this plug. You think it's to cold of a plug?

 

The correct plug for your engine is a RJ17LM

Engine manual:
http://www.cpdonline.com/692509.pdf

See page 5 for plugs:
http://www.tecumsehpower.com/CustomerService/BSI.pdf

 

Airman has the right info in the link he posted(( Thanks Airman)) In Northeastern Ontario,, we may have different spec engines I'm thinking,, 'cus I see lots of snowblowers & even push type lawnmowers from the factory with the "RJ19LM" plug in them.... I just kinda thought that was the one to use.... Nice & hot to burn the carbon off,,,,Right?? Square Head, Use the RJ17LM as Airman has suggested & you can't go wrong.... Roger

 

I use the J19LM in snowblowers even if it calls for J17LM. The J19LM is hotter and runs a little better in cold weather. Also seems to start easier.

 

Thanks for the BSI Manual. My Haynes manual is wrong then. My lawn mower takes the RJ19LM as well so this works great.
Thanks guys.

 

I ran into this before.I have na old champion spark plug cross reference book(haven't seen it since I moved) and some models do call for that plug.The heat range is important.It is ok to go 1 heat range hotter or colder than the plug called for but a plugtoo hot can cause the engine to fire at the wrong time because it stays red hot and this (red hot electrode) can ignite the fuel too soon.Additionally the plug could melt and break off.If too cold it will probably just foul the plug.IE,in racing bikes where engines are run at constant high speed,a colder plug might be ideal .One other thing,be careful that the plug is the same reach;too long will hit the piston or valve.G'luck