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  1. #1
    Join Date
    Sep 2021
    Posts
    5

    Default After filling up with 87 octane it wonít stay running

    2014 Moomba Mondo with Indmar 330. Just got it 2 weeks ago, 3rd time on the water with it. First issue.

    So at the pumps this weekend my buddy offered to fill it up and he put 87 in it. I forgot to tell him to put 89. Not sure if thatís what has caused this but after about 15 minutes on the water we were going about 40mph and engine started bogging/misfiring(?) and I cut the throttle down and it smoothed out around 3k RPMs. I opened it back up and it started sputtering so I backed it back down and turned back for the dock. It stayed at 3k all the way back with no issues. No fault codes or warning lights. When I got to the dock and put it in idle it stalled. Wouldnít restart. Today it will start but itís a very rough idle and stalls shortly after. Iím thinking itís bad gas or that the 87 octane is causing it. I plan on draining the tank which is 3/4 full and putting 93 in it and seeing what it does. Any other suggestions on what it might be and does anyone think 87 octane would cause this issue?

    Thanks!

  2. #2

    Default

    You have water in your gas.

  3. #3
    Join Date
    Sep 2021
    Posts
    5

    Default

    Thanks. Water in the gas was also something I was considering would cause this. Now to get it all drained and the water out 🤦🏻*♂️

  4. #4
    Join Date
    Sep 2005
    Location
    Claytor Lake, VA
    Posts
    573

    Default

    Might want to check your spark plugs.
    2005 Mobius LSV
    325 EFI

  5. #5
    Join Date
    Jan 2021
    Location
    Columbus, Ohio
    Posts
    641

    Default

    After you drain the tank, I would add a fuel treatment emulsifier to capture any water/fuel that you could not drain. It will also add some octane in the process and help clean the system out.

    I would also find the fuel rail test ports (look like tire valves) and drain fuel out of those. Water can foul out spark plugs, and damage injectors.
    2015 Moomba Mojo Surf Edition
    4,000lbs
    Manual Flow

  6. #6
    Join Date
    Sep 2021
    Posts
    5

    Default

    So after draining the tank, I did find water in the bottom of it. Not a lot but enough as there were puddles of water on both sides near the front of the tank. I was able to gain access thru the front vent with a rag to absorb the remaining fuel and water that I couldnít get out with my with the siphon hose. Also, somehow on the bottom of the front vent it was not sitting flush on the cylinder part of it. It had a little piece of plastic broken off on the white plastic cylinder piece and the middle piece of it was off center where the spring is. I was able to center it back up before putting it back on but I didnít see the broken piece inside the tank so who knows how long that had been like that. Should have it back together and filled up with new gas soon and will update if itís fixed. Thanks for the help!

  7. #7
    Join Date
    Mar 2021
    Location
    South Georgia
    Posts
    716

    Default

    Quote Originally Posted by Mondo14 View Post
    So after draining the tank, I did find water in the bottom of it. Not a lot but enough as there were puddles of water on both sides near the front of the tank. I was able to gain access thru the front vent with a rag to absorb the remaining fuel and water that I couldnít get out with my with the siphon hose. Also, somehow on the bottom of the front vent it was not sitting flush on the cylinder part of it. It had a little piece of plastic broken off on the white plastic cylinder piece and the middle piece of it was off center where the spring is. I was able to center it back up before putting it back on but I didnít see the broken piece inside the tank so who knows how long that had been like that. Should have it back together and filled up with new gas soon and will update if itís fixed. Thanks for the help!
    Sux that you had an issue with it, but great that you found all that. Probably answers your running issues!

    Sent from my SM-G781V using Tapatalk
    2021 Moomba Makai
    Black Cherry Metal Flake & Fire Red
    Nibral OJ 15.5x15 Altitude/Wake prop w/1.76 trans v-drive
    Wet Sounds Rev 8's, 10's, & sub

  8. #8
    Join Date
    Sep 2021
    Posts
    5

    Default

    Well after draining and drying and filling back up and putting 360 Sta-bil in it to remove any water left in the system and replacing the plugs it still idled rough. So I checked the spark on cylinders and I am not getting spark on cylinders 1,2 and 4. Those spark plugs were soaked with gas when I pulled them and I checked by cranking it with them all out and those 3 had no spark. Now to troubleshoot them.

  9. #9
    Join Date
    Jan 2021
    Location
    Columbus, Ohio
    Posts
    641

    Default

    Distributor cap and rotor cheap and easy to change.
    Mark and then remove....so many people mess up firing order during this job and such a pain to troubleshoot.
    2015 Moomba Mojo Surf Edition
    4,000lbs
    Manual Flow

  10. #10
    Join Date
    Sep 2021
    Posts
    5

    Default

    Changed the cap and rotor, made sure too mark and put wires in their right spots. All have spark now but back to a rough idle that sounds like it’s got a cam and runs smooth at around 3k rpms. All plugs are dry and look good after running it. Gonna put a timing light on it tomorrow and if it skipped time some how.

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