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Thread: Indexing Spark Plugs

  1. #1
    Member AKBassking's Avatar
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    Question Indexing Spark Plugs

    Hey everyone,

    Never heard this one. I have a 2005 Evinrude 250. It started to miss and was hard to start. I took it to the shop. The mechanic told me the plugs were shot! They were replaced last year and only have about 20 or so hours on them. (maybe a little more)

    Interesting thing, he told me the electrodes on the plugs have to be facing a certain way when installed in the cylinder. Has anyone heard this before?

    6 plugs, $250 later and I get my boat back.
    Last edited by AKBassking; 06-20-2007 at 16:58. Reason: Added stuff

    ALASKAN SEA-DUCTION
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    Blog: http://alaskanseaduction.blogspot.com/

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    Moderator Paul H's Avatar
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    Unless he used custom washers on the sparkplugs, how could they be indexed? When you torque down down a spark plug, where the electrode ends up depends on how the head was threaded, as well as where the thread starts on the plugs.

    The only thing I can think of is maybe the wrong heat range plugs were put in, only getting 20 hours on plugs sounds kinda fishy.

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    Indexing plugs is an old nascar thing. I have the washers to do that. How many fuel intakes ports are there in the cylinder? You are suppose to point the electrode right at the intake for a better burn of fuel If there is more then one intake then which one do you point it at? Like snowmobiles some cylinders have many fuel transfer ports so it really doesn't do a thing. If you really want them I'll send them to ya,

    GS

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    Cool Indexing

    Theoretically this works on 2 strokes because your intake/compression/combustion are all performed on one stroke and exhaust on another (hence 2 stroke). The side electrode should seat 180 degrees away from the intake side so the open area between the center electrode and side electrode faces the intake. Realistically, it doesn't make a difference and you will never see a performace gain on stock engines.
    On 4 strokes, it shouldn't matter cause the fuel/air mixture pre-combustion is volumetrically equal throughout the chamber.
    Your shop guy is full of BS and I would whip him with a wet noodle, then take your motor to a different shop. Oh, did he index the new plugs for you?

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    Next time you need new plugs I would like to make $250 for 6 plug install.

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    Member AKBighorn's Avatar
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    Quote Originally Posted by J-FRAME View Post
    Next time you need new plugs I would like to make $250 for 6 plug install.
    LOL, that's what I was thinking.

    Seriously though, on my 175hp sportjet I have had issues with performance the last couple of summers. I posted questions pertaining to it here and never figured it out until a couple weeks ago. It always started after fueling in Whittier, now that is just ironic. I had thought my problem was water. After fueling in Whittier yet again this year the problem reoccurred almost instantly. I changed the fuel/water separator filter and it help minimally. I didn't mention the initial problem was poor operation in mid RPM range. OK to start, idle and run 3/4-wot. So I changed the plugs, mine aren't typical plugs, just a plug with an electrode sticking straight out. It must arc on the piston or something. Anyway the plugs really didn't look bad, 1 or 2 didn't look as good as the rest but I never would have thought it would make that big of a difference. Now I have put many more than 20 hours on each set of plugs and these will clean up just fine but I am happy to finally put my finger on this and resolve it. The boat is 3 years old and it happened every year. I may or may not have gotten any water from the Whittier fuel dock but I honestly couldn't say either way despite my earlier suspicions.

  7. #7
    Member AKBassking's Avatar
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    He says he has indexed the plugs, but I am going to have him pull out the service manual and prove it to me before I pay the entire price.

    Will keep you posted.

    ALASKAN SEA-DUCTION
    1988 M/Y Camargue YachtFisher
    MMSI# 338131469
    Blog: http://alaskanseaduction.blogspot.com/

  8. #8

    Default Indexing Plugs

    I have seen it work on some engines, not all. Surface gap plugs will eliminate the need to do it at all. BUT.... The best spark plugs on the market, bar none are Irridium Spark Plugs. There is a distributor in Anch. Or you can go on line and get a cross reference chart for your boat. They work . Period. Go with the fine wire irridium and you will be pleased, Boats, Autos, Snowmachine, even your lawn mower. Check them out and I'll bet your problems get solved. As far as the gas in Whittier, I have heard the same thing numerous times. I was told by a friend that many of the coastal areas use a higher blend of water absorbing compounds in their fuel, due to the climatic conditions of the area. Hence they tend to burn hotter and sometimes eat plug faster and a large number of boat owners have to retard the timing a bit, to eliminate the pre-deadanation of spark, Knocking or rattling under a load is a sign of this happening. To test this, take a small Tobasco bottle and fill it half full with gas. Place a mark on the bottle. Finish filling it with water. Shake. If the gas level rises in the bottle, it has absorbed the water. The higher the level goes up is an indicator of how much additive has been added to the fuel.

  9. #9

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    Gas floats on water wouldn't the gas line go up because the water is on the bottom?

  10. #10

    Default Not Quite

    Quote Originally Posted by alaskamokaiman View Post
    Gas floats on water wouldn't the gas line go up because the water is on the bottom?
    The fuel additive is such that it absorbs a degree of water. The more additive, the more absorbtion, thus the higher level of gas will be noted from the original line. If there is no additive in the fuel, the level line of gas will not change.
    I should have mentioned earlier, my preferred brand of irridium plugs are DENSO. Many other manufacturers are beginning to produce them, but none have done as well as Denso, IMO.

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    Default Indexing plugs on ficht motors

    I can't speak for the newest e-tech motors, or for other brands of DFI 2-stroke motors (merc, yamaha, tohatsu/nissan), but for any johnson/evinrude ficht motor through the years, the plugs have to be indexed. Check this procedure:

    http://www.boatsetup.com/PlgIndex.pdf

    No shims - it's the luck of the draw, and a range of allowable torque which swings the plug into its correct position.

    It's not too ridiculous. I've changed plugs on a 175 three times now. At any given time, one hole might be a bit stubborn, but I've found that if I have 8 or 9 new plugs on hand, I'll get the six holes indexed pretty well. The extras I save for the next swap, and try them in different holes. You'll figure it out. It's way cheaper to order spark plugs online, but it only pays if you order a bunch at a time (shipping, etc.). Count on replacing plugs at least every 100 hours. For me that's once a season. That justifies a bulk order of plugs (20-30).

  12. #12
    Member AKBassking's Avatar
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    Quote Originally Posted by Vek View Post
    I can't speak for the newest e-tech motors, or for other brands of DFI 2-stroke motors (merc, yamaha, tohatsu/nissan), but for any johnson/evinrude ficht motor through the years, the plugs have to be indexed. Check this procedure:

    http://www.boatsetup.com/PlgIndex.pdf

    No shims - it's the luck of the draw, and a range of allowable torque which swings the plug into its correct position.

    It's not too ridiculous. I've changed plugs on a 175 three times now. At any given time, one hole might be a bit stubborn, but I've found that if I have 8 or 9 new plugs on hand, I'll get the six holes indexed pretty well. The extras I save for the next swap, and try them in different holes. You'll figure it out. It's way cheaper to order spark plugs online, but it only pays if you order a bunch at a time (shipping, etc.). Count on replacing plugs at least every 100 hours. For me that's once a season. That justifies a bulk order of plugs (20-30).
    I'll be dang. I thought maybe the mechanic was BSing me. I am still going to have him show me the shop manual. Thanks for the info!
    Last edited by AKBassking; 06-21-2007 at 16:23. Reason: add

    ALASKAN SEA-DUCTION
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    Blog: http://alaskanseaduction.blogspot.com/

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    Moderator Paul H's Avatar
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    Well, I'll be.

    If it's any consolation, they charged me over $400 to change the plugs in my wife's mercedes. I was going to do it myself, but they said you need special tools to remove the plug wires, and I believe it has 2 plugs per cylinder, so 12 plugs. I ended up begrudgingly coffing up the booty. The upside is you only have to change them every 100k miles, and I'm thinking we'll sell it before then. Her next one will be a diesel, no plugs

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    Cool Indexing-take 2

    There's a reason they call the DFI Evinrudes injection system "*****t" instead of Ficht. Changing 6 plugs every hundred hours with random threading, thus the need for bulk plug purchases is completely "*****t". Trade up and out of the Evinrude, you can do much better for less bling and actually be out on the water enjoying yourself.

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    When indexing the plugs it really is the luck of the draw, so to speak. You can try them in different holes but if they do not index correctly they have to be tossed. Before you spend any more of your hard earned cash try here:
    http://www.sparkplugs.com/
    I believe the Etecs and the newer Mercury Optimax's have to have the plugs indexed but the newer Yamaha HPDI's do not.
    Tennessee

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    You can order indexing washers from www.hiperf.com.

    I have never iondexed the plugs on any of the outboards I've owned. The 2005 Johnson 90, 115, 150, 175 hp. Service Manual says nothing whatsoever about sparkplugs except what kind recommended, and the gap.

  17. #17
    Member Magnum Man's Avatar
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    Smile spark plugs

    just an idea here

    Its not an outboard motor but on my big block ford I dont use anything but bosch platin plus 4 spark plugs. They have 4 prongs and you dont gap them. And they have the silver pltinum coating. Also you can get them in two prong version too. My good friend who has worked at the parts store for 8 years said they are desinged to to create a spark even when sumbmerged in oil.

    I threw a distributor drive gear last year and totally flooded my engine so bad it had pools fuel in the intake. After changing plugs twice and not getting started he sugg. those so I bought em a 6bucks a peice. they got the motor going. Sry bout the sales pitch but you cant beat these plugs with anything.

  18. #18
    Member AKBassking's Avatar
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    Default Update

    Well,

    I went to pick my boat up and asked about indexing. I was told that with the E-tec and DFIs they have to be indexed to prevent cylinder damage. I was shown the shop manual. So I guess it is just part of that black hole by which I throw my money down. Next year, I am ordering my own plugs and doing it myself.

    Snowwolfe, thanks for the website.

    Nitroman, The book specifically stated NO indexing washers/shims.

    I wish I had known that before dumping 16K into a new motor.

    Thanks for all the help!! PWS this weekend to burn them expensive plugs!!!!

    ALASKAN SEA-DUCTION
    1988 M/Y Camargue YachtFisher
    MMSI# 338131469
    Blog: http://alaskanseaduction.blogspot.com/

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