Sparkplug will not tighten - Craftsman 675 Torque 190cc 21" Briggs Stratton RearBag Push Lawn Mower (CA) ()

it is a process However here is a Youtube video that provides step by step. https://www.youtube.com/watch?v=HrhY-x5z8EU

Hi, try taking sparkplug out and get a screwdriver and put it in the sparkplug hole then gently move the stater round with a spanner untill the screwdriver moves up when it is as high as it can go tdc then take the screwdriver out, then put the sparkplug back in the ht lead and put the electrode part of the sparkplug on the side of the head then undo the stater and turn the ignition on,then turn untill sparkplug sparks,tighten stater,put plug back in it should start,then you will need to put a timing light on for fine ajustment.
good luck I hope this was helfull,PH.

try tightening a hair and then loosening,but be careful not to snap the plug,make sure you have a tight snug fit on it

Make sure the oil level is right. Check for spark by removing sparkplug and reattach the plug wire on it and ground the nut part of the sparkplug on metal on the engine. Whith the switch switch to on you should see a spark between the gap of the sparkplug when you pull the cord. If not get a new plug and make sure it is gapped to 30 thousands. If you are getting spark put the plug back in and tighten and reconnect the wire. Take the air cleaner off and put a spoon full of gasoline in the carburetor and pull the cord. If it fires for a second the carburetor has to be taken apart and cleaned.

Those are as easy as they come these days. Mark each spark plug wire with a piece of tape with the cylinder # written on it, so as not to mix up the wires. Remove each spark plug wire by firmly grasping the wire by the boot (do not pull on the wire) and twist it back and forth a few times while pulling slowly. It should pop off without a great deal of effort. If it is seized and it breaks, you will have to replace the wire, or at the very least replace the terminals (if you can get some). Use an air hose and blow around the base of each spark plug to dislodge any loose dirt that could fall into the cylinders (not absolutely necessary, but a good idea). Remove each spark plug with a spark plug socket and extension and ratchet (I forget which size socket, it's either 5/8 or 13/16). Check the gaps of each new spark plug (typically around 0.035 in). re-install each new spark plug by hand (do not cross-thread them) and once you have ensured that the plug is threaded in properly, tighten the plug until it seats, and then tighten an additional 1/16 of a turn. Repeat this for the remaining plugs. Re-install wires to the corresponding spark plugs. You're done!

Open the hood to access the engine compartment. Locate the sparkplugs sitting to the side of the motor. Six wires run to the motor, three on each side.

Twist the rubber boot and pull away from the sparkplugs. This will expose the sparkplug.

Unbolt the sparkplug with a socket wrench. Use a 5/8-inch deep-well socket attached to the socket wrench.

Pull the sparkplug away from the motor. Discard the sparkplug.

Screw the sparkplug into the motor by hand. Make sure it is hand-tight.

Tighten the sparkplug with the socket wrench, using the deep-well sparkplug socket.

Click the wire to the sparkplug wire to the end of the sparkplug. Gently pull the wire to ensure it clicks into place.

Repeat the procedure for the remaining five sparkplugs. Change each sparkplug one at a time.

In regard to the spark plug.Tighten it up untill it touches with the washer at the bottom of the plug.Now,go about 3/4 further in the turning of the sparkplug.This is correct.In regard to the milage,cant help without all the things you do with the m/bike.Hope this helps

the plugs you need are ac delco you can find the replacement proceedure on autozone.com vehicle repair guides

Classic valve train issues. Sounds like the valves are tight. One thing that concerns me is the "sudden onset". Valves usually tighten over time.
Make sure you also tighten the cam chain as well.