(Non Simp.-A/C) Mystery Plug Query

[JayM 0]

It's got me beat. . . .I have a project that's always parked behind the Landlord in the garage (so no one sees it!). It's a Bolens G14 with a Tecumseh HH140 (14 h.p.) engine. I need a new spark plug and can't find one. Here's the deal. The original manual for the tractor does not give a plug number. All the reference books I've looked at give plug numbers for this engine that are plugs with a different thread size than needed. The old plug in the engine is an AC R46S. From AC/Delco's web site, I understand that that's a resistor plug with a 14 mm thread, heat range 5, and extended tip. However, they don't list the plug as being in existence. Reference books give Champion, Autolite, and NGK equivalents, but none of the parts stores I've been to have any of the equivalents. So. . .I really have two mysteries: why do all the reference books list a plug for the Tecumseh HH140 that clearly is the wrong size? And, is there any place to get an AC R46S or its equivalent in another brand? There are still lots of those old engines around and running, so someone has a source for plugs. Any ideas?? Jay M.

[thedaddycat 153]

Is it possible that your engine has had the head replaced (with one that fits but uses a different plug) at one time or another, or that the plug hole had to be bored out and re-tapped? Just loose thoughts......to be valued in direct proportion to the price.

[JayM 0]

I was afraid someone was going to suggest that! Actually, both of those thoughts occurred to me, but I just didn't want to think about the possibilities. Unfortunately, I only know the history back through the pervious owner - which is about 1/5 of the life of the tractor.

[Dutch 4]

The AC R46S is a 14mm plug. Jack's Small Engines lists a Champion L82C as the correct plug for the Tecumseh HH-140. The Champion L82C is also a 14mm plug. Plug manufacturers frequently upgrade, consolidate, and supercede spark plugs. Just because the R46S may no longer be available, it has a replacement. Who says the R46S that you took out is the correct plug for the HH-140? Try the Champion L82C or the NGK equivilent B6HS, and take it from there. The NGK repalcement for the R46S is BPR4S. All are 14mm.