Thread: Oil cap leaking

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  1. #1
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    Oil cap leaking

    2017 Z18

    Hey guys,

    The oil cap on my tank is leaking. The smaller cap that connects to my remote oil fill. It’s not cross threaded and I have it on as tight as it will go. I don’t want to strip the cap. After being out on the water I can wipe oil off the cap with a rag. My pro xs is running rough on starts because I am losing my vacuum. Anyone have this issue?

    Thanks

  2. Member
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    #2
    My 2019 did the same thing. Dealer replaced the entire tank under warranty.

  3. Moderator Fishysam's Avatar
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    #3
    Could try some pipe tape, just make sure you put it on the the way that as you tighten the cap it's going with the tape. Start at the bottom of the threads and go 3 times around with a taper towards the top

    but I'm guessing that the starting rough is more likely a cause of the battery getting weak (what battery do you have?) and have spark plugs been changed?
    Mercury 250 proxs 2B115089

  4. Member
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    #4
    Just did new plugs, fuel filter and have all new blue top optimas . Not sure if it’s a fuel system issue or I’m losing my vacuum with my oil tank. Getting a better merc tech on it today.

  5. Member
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    #5
    The oil system is not under vacuum. It is under pressure. And it is unlikely to be the reason for rough starts.
    Is the reserve reservoir on engine staying full?
    Last edited by moetorola; 11-06-2019 at 09:20 AM.

  6. Moderator Fishysam's Avatar
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    #6
    Quote Originally Posted by moetorola View Post
    The oil system is not under vacuum. It is under pressure. And it is unlikely to be the reason for rough starts.
    Is the reserve reservoir on engine staying full?
    Agree, the blue top optimas are now made in Mexico to a lower standard from what I have read. Also read the optima blue top does not have the cranking power for a proxs
    Mercury 250 proxs 2B115089

  7. Member
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    #7
    Originally Posted by moetorola
    The oil system is not under vacuum. It is under pressure. And it is unlikely to be the reason for rough starts.
    Is the reserve reservoir on engine staying full?



    Agree, the blue top optimas are now made in Mexico to a lower standard from what I have read. Also read the optima blue top does not have the cranking power for a proxs



    My head just exploded from confusion.
    2017 Nitro Z21
    2017 250 Pro XS T2 (SN 2B401909)
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  8. Moderator Fishysam's Avatar
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    #8
    Your motor will not start rough from lack of oil, the crank case after it is running makes pressure that has a vent into the tank to pressurize it so oil will flow into the small bottle. So no motor ever gets oil from that tank during starting.

    the blue tops are made cheeper and are over rated on cranking power. Get a new real battery like a batteries plus x2 agm 31 and your problem will be fixed.
    Mercury 250 proxs 2B115089

  9. Member
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    #9
    Update:

    brought my boat to another mercury tech who was great..he hooked it up to the computer and looked through everything in front of me. He noticed my main belt was jumping all over the place. We took it off and it was bent out of shape. Also alternator was jumping all over the place. The bushings and bracket that held the alternator in place were pretty badly damaged and was digging in to the bracket. I have pictures but can’t figure out how to post them here. Also, apparently who ever worked on the motor last (bass pro who sucks) forgot to put back a small piece of the covering underneath the cowl. He said that could have caused grease to get on the belt and also cause it damage/Jump around while running. One thing he will be checking also is the tracker valve. All those parts are on order so I’m hoping this fixes my issue. I also showed him where I was getting my leak from at the oil tank, although he didn’t think that was my issue, he is going to look into it.