Yikes! Loose spark plugs!

Discussion in 'Boats, Motors, Trailers and Towing Rigs Forum' started by Fisherman Rob, Apr 19, 2015.

  1. Fisherman Rob

    Fisherman Rob Well-Known Member

    So I was poking around under the outboard cowling and I was shocked to discover that 3 of 4 spark plugs we LOOSE! So loose they were wobbling around in the socket. Last spring I had the local Yamaha service center check out the compression, which was all good. Since then I haven't really had a close inspection, but I thought it seemed recently a little slower to cold start. I had not notice any reduction in power, but I haven't had the boat that long. Is it possible that they didn't tighten them enough after checking the compression, or do plugs on outboard tend to work themselves loose?
     
  2. Nakoda boater

    Nakoda boater Member

    I highly doubt they worked themselves loose. They probably hand tightened them, walked away from the job then returned only to forget to tighten then and just reinstalled the wires. Once the wires are on the boots will hold the plugs in place... IMO
     
  3. spring fever

    spring fever Well-Known Member

    Yeah they forgot to tighten them!! I've had it happen before and usually at winterization!! Quality since Thursday!!!LOL
     
  4. gungadin

    gungadin Well-Known Member

    Have to agree, they were left loose. Good for you to catch it. Hopefully the threads are still ok in the head.
     
  5. Canso

    Canso Well-Known Member

    The crush washer on a spark plug acts as a gasket and lock washer, once it's been crushed it no longer acts as a lock washer.

    The crush washer should be replaced after every use, or second use if torqued properly.

    Re check your plugs after some use, they will probably come loose again...... Don't over tighten.
     
  6. gunnerlove

    gunnerlove Active Member

    Many people will say there is no need to use a torque wrench. Those people are the people with loose fittings and stripped threads.
     
  7. profisher

    profisher Well-Known Member

    I've never used a torque wrench on plugs, just rely on years of changing them and a feel for the right torque. Anyone index their plugs?
     
  8. KV1

    KV1 Active Member

    Always gap, antiseize, torque. Good sequence and good practice.
     
  9. Canso

    Canso Well-Known Member

    I have in high hp aplications, I've never noticed anything on 1/4 mile slips, but I still do it.
     
  10. gungadin

    gungadin Well-Known Member

    Always gap and torque. Have never indexed and don't use antisieze ( changes torque reading, affects heat range and could affect the ground circuit).
     
  11. bigdogeh

    bigdogeh Well-Known Member

    your right on this gungadin. unless the manufacturer of the plugs or engine calls for antiseize it may not be a good idea. I've never seen it called for though. and it will increase the "tightness " of the plug even at the same torque value with a torque wrench... which might not be good for the plug threads especially into an aluminum head.. may possibly stretch or even strip out the threads if done repeatedly over time... especially if the threads on the plug and head are fairly shallow.
    if you just have to use antiseize on the plug you should maybe find a sheet or guide that shows the value to reduce the torque when using a lubricated bolt (in this case a plug). but generally prob best just not to use it on a plug.
     
    Last edited by a moderator: Apr 20, 2015
  12. Fisherman Rob

    Fisherman Rob Well-Known Member

  13. bigdogeh

    bigdogeh Well-Known Member

    it's prob fine. you can prob find them a bit cheaper than that if you won't be using it alot. I'd also check out sears for a craftsman or even maybe someplace like princess auto and prob get one just as good for about half that price. just a thought... lordco, the tool place, etc... but prob nothing wrong with the one your link points to... 3/8" is good for spark plugs and smaller fasteners, but if you were going to use it for tire lugs or something a bit bigger you'd prob want to go to a 1/2" drive... but 3/8" will be fine for spark plugs and more suitable than a 1/2" wrench for that application.
     
  14. gungadin

    gungadin Well-Known Member

    It will work, but the spark plug required torque is at the high end of that wrenches capacity. Best accuracy for a torque wrench is about 60% of rated capacity. 3/8th drive is good for plugs as most spark plug sockets re in 3/8th drive.
     
  15. Fisherman Rob

    Fisherman Rob Well-Known Member

    Just had a look at one in a local auto supply store for $50. It was a 3/8" with 960 in-lb capacity. So the Can Tire one at 250 in-lb does look low.
     
  16. KV1

    KV1 Active Member

    There is Google and then there is reality. You don't globe it on and don't put any on the electrode. Heat transfer is a non issue and torque reading is negligible. If you would rather pull the threads out with the plug due to possible corrosion and or seizure be my guest but a little dab will do you. Any good mechanic will tell you the same;)
     
  17. profisher

    profisher Well-Known Member

    I have never used never seize on plugs but do on many other bolts that will have to come out to perform regular maintenance. It is good practice to put never seize on bolts that come in direct contact with saltwater and crystallized salt. Water jacket, exhaust, leg, zincs etc. The only exception is head bolts as proper torquing and staying torqued is important. I change the plugs every fall and have never had a stuck plug as they are not in long enough. Plug threads are not in contact with salt or saltwater. My motors are 18 year old Yamaha's
     
  18. Filletandrelease

    Filletandrelease Active Member

    I'm with you on this one KV1. I've seen and fought enough seized plugs in my day to wonder... Why didn't they use a bit of never seize or copper paste to avoid all this trouble
     

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