I usually use RJ19LM on most briggs engines. I think I have had 7 this year, and all of them used that plug with that gap.

Were you able to get on John Deere's site and look up the manual for that mower? That should tell you what you will need for sure.

 

-Yes I did, and it shows that the RJ19LM is the plug. But.... Here's a copy of part of the specs from JD. AS you can see, it shows that the engine is a 6HP, side valve Briggs. This mower has a 6.75HP overhead valve Briggs.

Engine

Manufacturer Briggs & Stratton

Model 12H802

Horsepower 4.5 kW (6.0 hp)

Cycle 4

Valve Type Side

Displacement 190 cc (11.6 cu in)

Choke Primer Bulb

Starter Recoil

Throttle Control Fixed Speed

Lubrication Splash

CARB/EPA Yes

Spark Plug Champion RJ19LM

Spark Plug Gap 0.76 mm (.030 in)

Spark Plug Torque 20 N·m (15 lb-ft)

Wheel Size 222x57 mm (8.75x2.25 in)

L8R,
Matt

 

ok found some more info just on Goggling briggs intek spark plug

Tune up kit Contains Briggs plug 491055S which crosses too
http://www.outdoordistributors.com/Briggs_And_Stratton/bsmaint.html

which crosses too Champion Spark Plug - RC12YC, Champion RC12YC, NGK BKR5E-11
http://www.hyperparts.com/wc.dll?ctwp~getxref~1001~1003~1~probrand~1~Briggs & Stratton~491055

Sorry I missed the fact that it was an OHV. This would make sense that it is a RC12YC plug.

Hope that helps.

Some additional info:
http://www.manddsmallengine.com/briggs/info/plug2.html

Edit button is back!!

 

Requardless which plug you install, gapped at .30 or .20 did it start better? Perhaps your problem has nothing to do with the sparkplug at all. I normlly use the RJ19LM plug gapped at .30 in most engines. here is the list of parts for your model of lawn mower:

Home Maintenance Kit For Models With Engines Marked 12H802 Includes paper air filter, spark plug, engine oil, fuel stabilizer and an oil change sticker. LG232 $13.25
Home Maintenance Kit For Models With Engines Marked 121602 Includes foam precleaner, paper air filter, spark plug, engine oil, fuel stabilizer and an oil change sticker. LG236 $25.50
Flat Paper Air Filter For Models Equipped With 6 Horsepower Engines LG491588JD $5.51
Oval Paper Air Filter Used On 6.5 AND 6.75 HP Engines Marked 121602 M147431 $10.24
Foam Precleaner Used With M147431 On Models With 6.5 and 6.75 HP Engines Marked 121602 M143275 $3.57
Quart 10W30 Turf-Gard Engine Oil TY22029 $3.99
Spark Plug For Models Equipped With 6 HP Engines Marked 12H802 Spark Plug Gap 0.030 Champion RJ19LM TY6129 $2.45
Spark Plug For Models Equipped With Engines Marked 121602-0112-E1 MIU11193 $5.21
Spark Plug For Models With 6.5 and 6.75 HP Engines Marked 121602-0280-E1, -0370-E1, -0528-E1, -0529-E1 M143270 $5.00
Transmission Drive Belt GC00073 $8.25
Standard Mower Blade GC00344 $12.75
High Lift Blade GC00175 $20.02

 

-Thanks guys. I haven't been able to get back down to my Brother-in-law's yet. Probably not til Tuesday. I picked up an RC12YC plug today on my way home from work though. I cleaned the carb when I was there last Tuesday just to make sure. Everything looked good inside when I pulled it apart, but ran a piece of copper wire through the orifices just to make sure. Also double checked the gap on the coil and the play in the valves. It still wouldn't start without pulling it 5-7 times. My Brother-in-law is in quite a bit of pain from having a couple ruptured discs in his back, so I'm trying to get his mower as easy to start as I can. Funny. his newer JD mower is a major pain to start, and my 20 year old Craftsman II with a little 3.5hp Tecumseh STILL starts on the first pull!

L8R,
Matt

 

-Well, that didn't work either. Still takes at least 10-12 pulls for it to even catch, then it stalls immediately. Maybe another 10 pulls or so with some stalls mixed in then it will start running. Once it's up and running, it runs great. Any other clues as to what it might be? This is a major irritation to both of us.

L8R,
Matt

 

The last one I had was a hard starter after a couple seasons because the carb gasget split where it bolts to the block.

 

-The gasket between the carb and head, and the carb and air cleaner are newer gaskets. When I pulled the carb off last week, the gasket didn't have any cracks or splits in it that I saw. This mower is a major pain in the keister! Once it starts and stays running, it runs perfect. I can restart it after shutting it off too. But if I leave it sit for more than 30 minutes or so, it's back to the pulling contest with the rope....

L8R,
Matt

 

i have had issues with intek in hard starting too. check valve adjustments and flywheel key . i had one i could never get to starteasy and just gave up on it and parted it out-never could find anything wrong with it. got tired or repairing the pull starter as i had to pul and pull to get it to start-once started -it ran flawless too

 

-I checked the valves, and they both ran at .005" clearance. What would the flywheel key have to do with hard starting if it runs fine once you get it going? Not too sure about what you're getting at. It may be that he just has a lemon lawnmower. I know the first few years he had it, it ran great and started with one or two pulls. I'm about ready to put a .38 slug in it and call it dead! At least I should only have to mow his yard a couple more times before the grass quits growing. At least then I can take my time and figure out what's going on with it. Maybe bring it home instead of checking it one day a week....

L8R,
Matt

 

Honestly what I would do is get on Craigslist and get him a nice 2 stroke lawnboy, that doesn't run. Clean the carb and it will run for a long long time.
Then sell that mower

 

-Well I "might" have found the issue. I clipped the electrode from an extra spark plug I had to make a spark tester. When I pulled the other plug and ground the tester plug, I could barely see a spark. And it didn't spark every time I pulled the rope. But when it did spark, it was a pretty weak looking one. So I guess that means the coil is on it's way out. I must have checked the spark the last time when the coil was behaving. Time to look up a new one...

L8R,
Matt