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mercruiser 165


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I just figured I see if anyone has any 2 cents out there. engine block says to gap spark plugs at .35 but when I pulled them they were all set between .40-.50? Just seeing if I'm missing something there cause I thought that was kinda outta wack? The spark plugs looked bad anyways so I just replaced them and the plug wires and gapped back to .35. One thing I noticed is one of the spark plugs seemed gunky or wet (oil or gas, not sure). Could this be related to the offset gaps or should I be having the motor looked at for some type of leak? is this serious or am I just being overly concerned? thanks!

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i would run it with the plugs gapped at 35 and re-check the plugs. If the gap is "too open" it will not fire "hot enogh" and will not burn off all the fuel. Now if it is still there after the the new plugs and it is fuel not oil check all your plug wires, cap and rotor etc to make sure there are no issues. if you find out it is oil i would have it looked at

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I would set the gap at .030 and run the motor awhile then pull the plug and see what it looks like, if its still $hitty looking put the plug somewhere where you can see it when turning the motor over and observe the color of the spark should be bright blue, if yellow then maybe time to replace wires, or at least that one, could be rubbed through and grounding out elsewhere. To do an easy check take the motor cover off at night and fire her up if you see any arching time to change all the wires, try to keep them from lying against anything metal, use zip ties or a plug wire loom to keep them away from each other and lying against anything metal, if still finding a crappy plug you could do a compression check and see if that cylinder is down, all though if a oil ring collapsed it won't show up on a compression check, sometimes they get hung up in the piston, try some SeaFoam in the oil, follow the instructions on the bottle. This did the trick on a old 140hp mercruiser I had, with similar problems, I doubt it's a valve problem or you would have back firming through the carb. Hope this helps and keep us posted. PAP

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Yesterday I replaced plugs with some ac delcos and picked up a quicksilver wire kit. Seemed to fire up quite nicely. I'll take it out this weekend and hopefully things work out. If the plug garb up I'll have to try some seafoam in the oil

Sent from my iPhone using Lake Ontario United

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