How much to tighten spark plugs

[Ronnie]

I wouldn't use a torque wrench, unless you have a torque spec. The illustration is deceiving IMO. It doesn't even illustrate a 1/2-2/3 turn.

I’ve got the spec but the last time I used a torque wrench o had to turn the plug in a lot further than I would have by hand/per the illustration.

 

[HangOutdoors]

Well I can still feel and envision the moment that I snapped a plug in my car many years ago, every time I turn a spark plug in in the boat engines. The snap is unmistakable as well as the feeling. I don't remember how it felt when I got married, but I will never forget the feeling of snapping that plug....... Don't get me even started on when I cross threaded a plug in the same engine and tried to fix it with the wrong tapper so then the hole was too big for the spark plugs....

 

[Cobra Jet Steering LLC]

I use never seize on all my plugs, very light on the bottom threads so I use a different process I never use a torque wrench on plugs but I have many decades of experience, the usual position is get it snug and go 1/2 to 3/4 of a turn more and stop. Yamaha has a bad reputation of plugs being hard to remove or snapping off when removing them , I believe the end of the plugs go past the threads in the head and that part of the plug gets dirty from being in the combustion chamber thus creating issues when removing it, Then if someone puts a lot of pressure on the wrench they can snap off the end of the plug. I also use dielectric grease on the coil boots to prevent the boot from adhering to the top of the plug.

 

[RobbieO]

I’ve got the spec but the last time I used a torque wrench o had to turn the plug in a lot further than I would have by hand/per the illustration.

Remember you're seating the sealing ring. I've been a mechanic all my life. I just tighten them until I feel the ring collapse and seat. It's a feel thing.

 

[Ronnie]

Remember you're seating the sealing ring. I've been a mechanic all my life. I just tighten them until I feel the ring collapse and seat. It's a feel thing.

That’s what I do now, stop turning after I feel the washer collapse and the slightest indication that I’ve reached the limit. It just so happens that it’s about a half turn past hand tightened.

 

[1BadTundra]

Ugh... That moment when Righty Tighty turns into Righty Loosy!!!

 

[deubank1776]

Well I can still feel and envision the moment that I snapped a plug in my car many years ago, every time I turn a spark plug in in the boat engines. The snap is unmistakable as well as the feeling. I don't remember how it felt when I got married, but I will never forget the feeling of snapping that plug....... Don't get me even started on when I cross threaded a plug in the same engine and tried to fix it with the wrong tapper so then the hole was too big for the spark plugs....

My friend had an overgrown pontoon boat and they couldn't get it started. It had fuel, air, battery was good so i though hmm, maybe spark. When I took a look at the spark plugs the middle one was cross threaded to unholy hell. I said suggested they needed to get a tap and a collar. So I did it for them. I began to re tap the hole and I mean a lot of material was taken out. His dad insisted on using grease on the tap and I being a sixteen year-old kid was like "I know what I'm doing thanks tho." Man I could've gotten whooped. But I ended up fixing their outboard and it started right up. Cross thread is the worst. I had a 16' Jeep Wrangler and seemed like every bolt on that POS was cross-threaded or seized. Brand New too.
For spark-plugs its hand tight then a quarter turn and make a click with your tongue to simulate a torque wrench!