Spark Plug Help

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Feb 16, 2005
Scituate MA
After 3 seasons on the mower and 4 on the trimmer I decided to pull the plugs. They were easy enough to take out.

1. I just google it "spark plug 796112" but they had a letter 's' after the numbers, is that the same? Is that the way to find them just line up the numbers on the plugs?

2. (Sorry...this is awful) Do I clean the socket area out with anything? Do I put some grease on the threads before reinstall? (Sorry...haven't done it before).

Appreciate advice/recommendations.
The 796112s replaces the 796112, no problem.

Do clean around the spark plug hole, you don't want junk getting into the cylinder. Ideally you'd clean it before you remove it, usually with compressed air.

Wipe around with a clean rag and you'll be fine.

No grease on the spark plug, just put it in dry. You could use some anti-seize but just a literally a drop.
I usually put just a dab of 'anti-seize' on the plug threads, careful to not get any near the electrode.

Besides the web, most any 'Auto-Zone' type store would help you cross reference for plug type. I usually do it on my own though.

Plugs are cheap, depending on the small engine they should be changed out once in a while. Plug deterioration can vary a fair amount between engines and amount of use. As a ball park I may change a plug every 1-4 years, condition upon inspection is key.

I may also get a better quality plug when I do replace one.
Oh..I was all proud of plug in the mower, started on first pull.

I looked in the cylinder area of the trimmer, looked awfully dirty. Go with the new plug or should I spray something in there. I don't want to get in to a mess of taking the whole thing apart.
You looked in through the spark plug hole?

Leave it. It's going to be dirty with carbon. Don't spray anything into it. Too much can hydrolock the engine. You might also knock some carbon off where it gets picked up by the rings and scratches the cylinder.
Briggs & Stratton 796112 spark plus is a Champion RJ19LM. I just run the Champion RJ19LM in that application. They sell for less than $2 at Wal-Mart.

As far as the trimmer, if it came with an NGK plug be sure to put a NGK plug back in. They are notorious for running terribly and at lower RPM/power when running a different brand spark plug. If this is a lower end trimmer, then this probably doesn't apply to you.
Originally Posted By: Audioquest
If it came with a Champion RJ19LM, replace it with an NGK BR2LM. Much better spark plug.

Or at least the higher-end Champ RJ19. There is the plain-Jane Mexican-made Champ, and the $1 more expensive fine-wire US-made Champ. Bought the latter for $3.30, and it works fine in the snowblower it was put into. The comparable NGK was special-order for $7. Not sure if the NGK is worth 2x the cost here.
Originally Posted By: Audioquest
If it came with a Champion RJ19LM, replace it with an NGK BR2LM. Much better spark plug.

They are both resistor plugs. Both are excellent quality, about on par with each other. I wouldn't say the NGK plug is "much better" than the champion. In other applications, sure, but not THIS application. The Champion is made in the USA, while the NGK is made in Japan. I've used hundreds of the RJ19LM and never had a problem. Well I have also used a few dozen of the BR2LM as well and have never had a problem.
I have never understood the hate for Champions. If they make a plug for my applications, I would use them. For years they were about the only small engine plug. B+S used J8s, same as my Willys.
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