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  1. #1

    Default 3116 taking longer to start

    I have a single CAT 3116 with approximately 1600 hours on it over twelve years. Up until recently the engine would fire up and run fine the instant I pressed the START button. Even the first start after winter layup. Recently, however, the engine takes a few seconds of cranking before it fires up. Once started, it runs beautifully as it always has, but this need to crank a few seconds is a totally new development. The Racor element has been replaced and the filter bowl drained. The CAT filter on the engine has less than 125 hours on it. What could be causing this harder starting, and what is to be done about it?
    Jim B.
    Last edited by Jim B 3116; 09-15-2012 at 10:26 AM. Reason: Added more info

  2. #2
    Join Date
    Sep 2010
    Jersey Shore

    Default Re: 3116 taking longer to start

    Change all the filters. Make sure you are not getting air in the fuel system.
    Dockside Marine Services
    Jersey Shore.
    Mercruiser/Mercury Certified
    Let the insanity begin.

  3. #3
    Join Date
    Jun 2008

    Default Re: 3116 taking longer to start

    Air leak in the fuel system, really dirty air filter, low compressions. Not that many other options really in an engine that is otherwise running well. Don't know on a 3116, but we had a similar issue on a Volvo recently that was traced back to a pin hole in the lift pump diaphragm letting air in.

  4. #4

    Default Re: 3116 taking longer to start

    We run 3126's and the starters need a good set of leads to the battery or they turn the engine weakly. Similar symptoms traced to the main Ground wire (thick as your thumb) which had broken inside and less than 20% of the conductor was intact. Crimp, Solder and then Heatshrink if you make a new set up. Can also be a bad cell on a battery.

    I put a set of industrial jumper leads onto the Starter Terminals and a known good battery and the motor fired instantly (on the key) - proving starter strong and fault in leads or battery.
    Repeated with leads to original battery (in parallel) and starter and also instant so battery good. Replaced both Main Leads and problem gone. Cut insulation off old leads and found internally burned and frayed near terminals

    If you need a new starter and don't fancy the grand that CAT original cost, I go to Maako - they also deal with a lot of air-starter stuff and knew it was a CAT Marine engine as soon as I said CounterClockwise MT42

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