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Need Help! Fuel Prime Problem

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  • Need Help! Fuel Prime Problem

    Merc. '94-225 3.0L Carb. recently began to loose prime right after cranking up. The bulb get soft and slowly dies out at forward idle unless I pump the bulb. If I get up to speed on her then fuel pump picks up and everything is fine. But just looses prime at forward idle.

    Thanx, any help is appreciated in advance.
    Justus[br]\'93-211 Classic [br]Baton Rouge

  • #2
    .... uummmmmm .... uuummmmm .... Did you put a new fuel filter in by any chance? Ya know, it makes a differnce which side you plumb the tank and engine to. How do I know this? I just do, ok.... and I don't want to talk about it. [(#)][]

    Seriously, I replaced the Racor seperators and mounts to the new SS ones (Warthog posted the site a while back). I put the hoses back on the same way the old mounts were run. NOPE. The IN and OUT are different on those and this created an airlock inside the filter. Had the same symptoms you describe, and if not for Dave and his Michigan tractor cranking bulb action, I never would have gotten prime again. The IN/OUT were run correctly and now everything is fine.
    Artie Sutherland[br]Rude Attitude -\'76 Mako 25 CC. - SOLD[br]1976 Mako 21[br]2002 Yellowfin 31 - 300 hp Suzukis[br]Gulf Coast, Mississippi[br]


    • #3
      Rude, I didn't change out the separator, but did recently just replace fuel line from the separator to engine and also replaced the bulb. All quality material. Premium USCG app. fuel line and Sierra bulb. None of that Walmart cr**. Hose clamps all tight. I'm wondering if i have a diaphram problem? I did change those out as a matter of precaution about three years ago, you know that rubber material gets brittle. What about the new fuel bulb. Maybe the check valve isn't working properly. What a dillema [:-(][?]
      Justus[br]\'93-211 Classic [br]Baton Rouge


      • #4
        I know the tempo bulb's are a POS. Not sure about the one you bought. I tell people to get the factory one that their motor is.


        • #5
          Wart, thanks for chiming in. Do you think it's the bulb? I would hope so, that would be the least of my worries. I got the Sierra bulb from the Merc. dealer here in B.R. Didn't think twice to ask them whether it was OEM.
          Justus[br]\'93-211 Classic [br]Baton Rouge


          • #6
            Here is a very good article on primers and how to install and troubleshoot.

            [br]1994 Mako 215 Dual console Optimax 225[br]1978 Mako 19 with 90hp johnson[br]1996 Mako 22[br]1982 Mako 171 Angler 135 Black Max Mercury[br]1987 21b 225 Yamaha[br]1974 23 inboard Gusto gone.[br]1979m21 225johnson \"blue dolphin\" bought off this board and restored [br]with everyone\'s help!!Gone but not Forgotten....[br]1979 20 Mako 115 Suzuki gone[br]1977 19 Mako 115 Johnson gone[br]1976 23 Mako twin 140 Johnsons gone[br]1983 224 with closed transom and bracket[br]And 162 SOB (some other boats)[br]Venice Florida, Traverse city Mi.


            • #7
              The bulb has a check valve in it and at low speed, if the check valve is faulty, you can loose prime.

              Sometime ago there must have been quite a number of bad bulbs on the market since Merc recalled the ones they shipped with my motors in 2001. Both mine were bad and had to be replaced immediatly.

              New bulbs solved my problem.

              [br]***[br]\'82 Ski Nautique - Lake Martin, AL[br]\'80 236IB - Lake Martin, AL[br]\'03 Pursuit 2670 - Destin, FL


              • #8
                Yes, I'd say bulb, too. There's not alot to go wrong with hoses as long as they're not crimped, crushed, or melted. The only other hose precaution is not to run them too high in the boat (that liquid lifting thing). Anyway, I've seen a bulb do this before. I know it's a stupid question, but do you have the bulb pointing in the right direction on the hose?

                18ft MonArk tri-hull: 140HP Mercruiser Alpha One - still in be continued[br](I know it\'s not a Mako, but hey, its mine!)[br] Time\'s fun when you\'re having flies![br]president/hostmaster:[br]P.Ring Technologies[br]Cornerstone IT, LLC[br]LOUISIANA WEB HOST, LLC.[br]CompTIA Certified Professional A+/Network+ // Microsoft Registered Partner


                • #9
                  How old is the tank? I had the same problem and it was the bulb. I was told that the new additives they put in fuel today actually break down the components in the older primer bulbs. Now I have that problem again, and bypassed everything and think i have a blockage in the tank[:-(] there's a check valve in the pick up fitting at the tank, so it's either that or debris in the pick up, uggggghhhh
                  [br]Michael R. Delgado[br]1972 Mako 22[br][br]1976 Mako 25[br],25[br]


                  • #10
                    Allright, looks like the general consensus seems to be a bad primer bulb. Simple enough. I'll r/r and see if this solves the problem.

                    Thanks to all who offered their advice. [)]
                    Justus[br]\'93-211 Classic [br]Baton Rouge