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Ultra 150 Plugs Fouling

This is a discussion on Ultra 150 Plugs Fouling within the Kawasaki forums, part of the Technical Support category; I have been having trouble recently with pulgs fouling on my 2001 Ultra 150. Had it in shop twice, both ...

  1. #1
    LuvToSki is offline On the 2nd tank
    Oct 2005

    Default Ultra 150 Plugs Fouling

    I have been having trouble recently with pulgs fouling on my 2001 Ultra 150. Had it in shop twice, both times, they replace the plugs and say can't find anything wrong, water test, runs fine. After 4 hrs, plug start fouling again. Always seems to be #1 plug, then #2. Appears to be gas starved and fouling from oil. I also notice the fuel filter is practically empty. Checked fuel lines, filters and check valve, all ok. Thinking the pulse fuel fitler is weak, given the order that the plugs foul (furtherest away first) and the fact that it can't seem to keep the filter full of fuel. If the pump is pumping correctly, shouldn't the filter be almost full?

  2. #2
    Luckyghost's Avatar
    Luckyghost is offline New skier
    Sep 2005
    So Cal - The Parker Strip

    Default Re: Ultra 150 Plugs Fouling

    shouldn't the filter be almost full?
    When I was running the stock carbs on my ultra the filter was always about empty. After I did change to Buckshot50s, got a new mukini fuel pump, an auto part standard paper filter and the pulse line going to the pump (Line seemed to be OK but I change it anyway) now the filter is almost completely full all the time. I'm not sure what was exactly responsible for the change of the amount of fuel at the filter.

    You may want to try the NGK Iridium spark plugs. They are expensive but lots of people say that they never get any fouling using them. Here is a link about them at NGK:
    Don't take life so seriously... You will never get out alive.

  3. #3
    LuvToSki is offline On the 2nd tank
    Oct 2005

    Default Re: Ultra 150 Plugs Fouling

    Thanks, but something is obviously wrong other than plugs. Ran same set for first three years, no problem, now been thru 4 sets with less than 15 hours. Appreciate the info on your fuel filter similarity though.

  4. #4
    John Kubiak's Avatar
    John Kubiak is offline PWC Pro
    Aug 2001
    Las Vegas, Nevada

    Default Re: Ultra 150 Plugs Fouling

    Many times, in the many years I have been working with many different types of vehicles and engines I have found a common installation mistake made by many people; novice and expert alike.


    The specs are 17 foot-pounds or 1/2 to 2/3 of a turn after the crush washer touches the cylinder head.

    This can and will have a direct effect on spark plug life, and the plug's ability to resist fouling.

    This is quoted directly from the NGK Spark Plug website:

    Athough this website does not specifically state "for PWC" the same data applies.

    "Torque is one of the most critical aspects of spark plug installation. Torque directly affects the spark plugs' ability to transfer heat out of the combustion chamber. A spark plug that is under-torqued will not be fully seated on the cylinder head, hence heat transfer will be slowed. This will tend to elevate combustion chamber temperatures to unsafe levels, and pre-ignition and detonation will usually follow. Serious engine damage is not far behind.

    An over-torqued spark plug can suffer from severe stress to the Metal Shell which in turn can distort the spark plug's inner gas seals or even cause a hairline fracture to the spark plug's either case, heat transfer can again be slowed and the above mentioned conditions can occur."

    Make sure to properly gap/install/torque your spark plugs.
    John Kubiak
    Powersports Technical Training Professional
    Las Vegas, Nevada
    Sea-Doo Tech 13736
    PWC Tech since 1988 (22 years)
    PowerSports since 1976 (34 years)
    Please do not use Private Messaging, use the forums.

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