Spark Plug Torque Specifications??

[willmann817]

I have a 2021 Mercury Pro XS 200 (V8) with serial number 3B103421.

The engine has 35.4 hours. I have a Vessel View Mobile installed.

Engine started running rough. I have a 2022 Tracker V18 Combo that I use for fishing.

I have read elsewhere in this forum that it seems if there is a lot of low RPM time that spark plugs could need changing well before the 100 hour mark. I get where I am going on a small lake (Hillsdale Lake in Kansas mostly and others of similar size) and spend most of the time trolling on the electric Minn Kota.

Engine started rattling a bit and didn't sound quite right but not getting any codes. I use Quick care fuel treatment from Walmart. Usually use regular gas from high volume stations.

I know it says 15 foot pounds for salt water (which I don't go in). I don't have a torque wrench on my ratchet.

How tight (how many turns after hand tight) would I turn after ensuring the gap is correct? Hopefully this resolves the issue. All help is appreciated.

Thank you -Will

[lpugh]

Must have a torque wrench, rattling? you better have this checked out before you run it again,

[mactlman]

10-20 ft lbs is usually torque on plugs with a tapered seat (about 1/8" movement after snug) -- gasketed plugs turn 1/2 to 3/4 turn after bottomed out on washer

[cottonpicker]

15 ft lbs

[willmann817]

This is the last time I ran it. Maybe rattling isn't the best word. Here are some short videos if it helps anyone make a guess or confirm it is the spark plugs or maybe fuel filter or bad fuel? https://photos.app.goo.gl/2PJSK6t24qXtmaQy6

[fly by night]

Buy yourself a good quality, accurate torque wrench.

[lpugh]

This is the last time I ran it. Maybe rattling isn't the best word. Here are some short videos if it helps anyone make a guess or confirm it is the spark plugs or maybe fuel filter or bad fuel? https://photos.app.goo.gl/2PJSK6t24qXtmaQy6

Get this motor checked by a Pro, not likely just a spark plug problem.

[willmann817]

Thanks Leon! I called Bass Pro and they are a couple weeks out. I have another Mercury approved shop I am about to call as well to see if they can get me in sooner.

[EuropeanAM]

This is the last time I ran it. Maybe rattling isn't the best word. Here are some short videos if it helps anyone make a guess or confirm it is the spark plugs or maybe fuel filter or bad fuel? https://photos.app.goo.gl/2PJSK6t24qXtmaQy6

Replace plugs, make CERTAIN you do not pull on the wires at all (use a spark plug plier to remove boots by grasping the square at the top of the plug boot).

If any wire doesn't snap to the plug properly and remain firmly attached, STOP and get a new set of wires.

GREAT idea to test your wires (need Service and Diagnostic Manuals for this).

TORQUE PLUGS TO <EDITED> 15 LBS/FT, or 180 lbs/in. THERE IS NO OTHER PROPER/ACCURATE INSTALLATION METHOD.

That engine sounds and appears to simply be misfiring in the videos. The sound I hear is idle relief/exhaust, could not perceive any real "knock" from monitor and speaker method.

Don't push your luck on it: If you're not 110% confident in changing, gapping, and properlly torquing spark plugs, STOP HERE and seek assistance. Much beyond the plugs and wires you'll likely need assistance, hands-on.

[Fishing Addict]

TORQUE PLUGS TO 15 LBS/IN, or 180 lbs/in. THERE IS NO OTHER PROPER/ACCURATE

Don, not to question your authority, but, did you possibly mean 15 lbs/ft or 180 lbs/in?

[willmann817]

I think he did make a mistake. Thank you both for the responses!

I took the engine to the mechanic at my local marina to diagnose. They tested the spark plugs with a tester and found no problems and reinstalled them to proper specifications. They checked wires and coils as well.

They also checked the fuel and oil and said it all looked good.

They used a computer to see if it was showing any codes that my VesselView was not showing.

It showed them 2 unknown codes and since they are not an Official Mercury Dealer or Partner they recommended to take it to Bass Pro (where I bought it) since it is still under warranty. I dropped it off yesterday and I am waiting for response. If Bass Pro says it is good. I will still install the new spark plugs I bought yesterday and see if that works.

Hopefully they can read the codes and get higher level mercury support if needed. The mechanic shop at the marina says they do not get any support from Mercury when they call, but that Mercury dealers have access to proprietary software to read the more in depth stuff. Kind of like the difference between a regular ODB II code reader vs an Autel full diagnostic tool that can read all the systems in a car (from air conditioning to electrical etc).

Thanks again and I will keep you all updated.

-Will

[cottonpicker]

Also like Don stated about removing plug wires only by square portion of plug wire is 100% true but still does not guarantee that the plug wires will snap back on your plugs after removal. Very poor design on the wires.

[EuropeanAM]

Don, not to question your authority, but, did you possibly mean 15 lbs/ft or 180 lbs/in?

Good catch! It is indeed 15 lbs/FT (or 180 lbs/in).

[willmann817]

@EuropeanAM and all others. I know the topic was originally the spark plug torque specs since I wanted to change the spark plugs based on the issue I was having and research I had done on here prior. First reputable mechanic I took it to was not a mercury partner and they said it was not the spark plugs and they had tested them. Then I took it to bass pro since I had "ruled out" the spark plugs (even though I bought 8 new ones from oreillys auto parts). Bass pro ended up telling me it was the spark plugs and had already replaced them and boat is running normal. Now I have 8 new spark plugs for next time. Very strange with low hours but apparently those low RPM hours take their toll and even if the spark plugs test well on a tester the engine just don't like 'em I guess.

Thanks again for the help and the torque specs!

-Will