B&S spark plug torque?

[y_p_w]

Here's the deal. 22" Craftsman mower with a 4.5 HP B&S "Reliable Starting" engine. I can't match up the label to any engine number in B&S's online owner's manuals. Also - I can't find any plug installation torque specs on the B&S website.

I pulled off the factory OE spark plug to have a look. It was a tiny bit oily, as I'm using Mobil Drive Clean Blend 10W-30. The OE spark plug was a slightly relabelled Champion RJ19LM; It says Champion/RJ19LM with the Champion logo on one side, and has the B&S logo on the other side. It also says "BS" on the hex edge. It also looks the the plug was installed before the engine was painted. There's a little bit of excess paint on the body and ceramic. I bought a replacement plug, but I'm not going to install it until next season. I was also looking for the NGK equivalent (BR2LM) but a power equipment shop didn't have it, and an auto parts store couldn't order one (they had Champions).

Anyone know what installation torque for the plug? I found an independent FAQ that says 15-30 ft-lbs, but I'd like something a little more precise than that.

 

[oilyriser]

Maybe they meant 30 inch-pounds? 30 ft-lbs will probably strip the threads.

30 or 15w40 should solve the oil contamination problem.

 

[Hokiefyd]

Typically, a spark plug is about 14 lb*ft. Just tighten it until it won't reasonably go any more with a spark plug wrench. Don't lean on it by any means.

Another method is to thread it until it seats, then add 1/4 turn for a non-gasket type, or 1/2 turn for a gasket type.

 

[Matt_S]

IMHO, using a torque wrench on a spark plug is going overboard. I don't think they even publish a standard, and I've just looked at 4 different manuals on the B&S web site. None even mentions a guideline as to how tight. The only thing mentioned is the gap and replacement interval. Good and snug is the standard I use. I've never had a plug come loose, even on the most vibration-riddled two strokes.

 

[y_p_w]

quote:

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Originally posted by Matt_S:
IMHO, using a torque wrench on a spark plug is going overboard. I don't think they even publish a standard, and I've just looked at 4 different manuals on the B&S web site. None even mentions a guideline as to how tight. The only thing mentioned is the gap and replacement interval. Good and snug is the standard I use. I've never had a plug come loose, even on the most vibration-riddled two strokes.

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I was used to checking long life spark plugs on my cars. I pretty much had to use a torque wrench since the gaskets were already compressed.

B&S publishes tightening torque specs for its go-kart engines. I saw one guide that said "180 in.lbs". However - that was for a 5/8" drive plug. The RJ19LM is 13/16".

http://www.briggsracing.com/model20engine3.html

I'm still not that sure that I should keep on using a Champion plug. It's been drilled into me that they now make crap. I can't readily find any alternatives though.

 

[y_p_w]

I ended up tightening it with my beam-type torque wrench up to 180 in-lbs (15 ft-lbs). Seemed a little tight, but it didn't strip the threads. I removed it and the threads were fine. I was worried that the plug might shoot off if it was too loose. The gasket method wasn't going to work with the used plug.

I realize the 10W-30 oil is probably the cause of the excessive oil blowby. One morning I started it and there was excessive smoke and oil spraying out of the exhaust. I'll probably just drain and replace it with the starter bottle of lawnmower oil and get some cheap SAE 30 next season.

 

[Matt_S]

I've never had a problem with Champion small engine plugs. I wouldn't use them in my car, given that there are much better products available, but engines for power equipment are, as a rule, pretty old technology. Most still use a flathead, side-valve design and very low compression. This puts very little stress on the ignition system. As long as you get a plug that fires reliably and with a half decent spark, you'll be fine.

 

[DaveJ]

I have built a few 12 and 13 to one compression engines and we have pulled the plugs to "read" them then reinstalled at the "Hand tight plus 1/4 turn" with the used gaskets. Never blown one out of a head yet. Champion is and always has been the Spec plug from Chyrsler. I dont use ther standard replacement plugs but I do use the "TRUCK" plugs as the electrode is thicker and will not cause a miss-fire from the side electrode glowing like a thiner one. A Splitfire type plug side tip does glow red and dis-color from heat and at 13:1 CR and 7000 RPM thats not a good thing. I think 180 In/Lbs (15Ft/Lbs)is the MAX I would try but IMHO is way too much. I am not wanting to start a sparkplug "WAR", just my 2 bits worth. DaveJ

 

[BUBBA0420]

Forget the Champions. You can order the NGK
BR2LM from www.sparkplugs.com. I put one in my
Rototiller with a 5HP B&S and it starts first
pull every time