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Why is porting necessary?

Discussion in 'Chainsaws and Power Equipment' started by bushpilot, Jun 28, 2015.

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  1. MasterMech

    MasterMech The Mechanical Moderator

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    Marine 2-stroke oil ratios are most certainly driven leaner by environmental factors, much more so than outdoor power equipment. Those engines exhaust in direct proximity to aquatic environments and public water supplies.

    I'm no expert in that particular area but I'm pretty sure at least some the new outboards running extremely lean oil ratios are lubing the bearings and other bottom end components directly instead of relying on the pre-mix to do it. Also the more sophisticated motors can vary the oil injection systems based on engine rpms and load.

    I do agree that modern oil is a big reason we can run 40:1 and 50:1 (or even leaner) reliably in stock equipment. Ratios like 12:1 or 16:1 are from the days of mixing straight 30wt automotive engine oil in the fuel. 32:1 on modern day synthetic oils is more than enough to lube your favorite saw from decades past.
     
    MasterMech, Jul 16, 2015
    #121 Top
    pantelis and Fifelaker like this.
  2. clemsonfor

    clemsonfor

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    I wear muffs. Weather on a quiet saw or a hogged out ms650
     
    clemsonfor, Jul 20, 2015
    #122 Top
  3. clemsonfor

    clemsonfor

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    And a lot of those late 90s and early 00s motors (OMC...which is what I run) have a VRO delete pump. Thats why they made the special motors in those early years like the 28,48,88 special...no oil injection for those of us who dont want it. I run 40:1 premix in my older ones. Still want to put the vro delete pump on my 91 javelin. I dont Thursday the early premix.

    Remember at a certain era OMC event to recommending 50:1 in ALL their out boards. Then for a period of time certain motors were recommended do run 100:1... to many burned up and they went back to 50:1. I run the walmart two stroke oil in mine which tons of guys run in their older OMC motors and everyone is happy with it that I have read over the years. I run older stuff but I also mix it at 40:1
     
    clemsonfor, Jul 20, 2015
    #123 Top
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