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  1. #1

    Some random thoughts about oil pump block off

    kay so this could just be totally wrong (I am by no means a mechanic or a mechanical engineer......) So I bought a ski with oil block off but 2 lines running to the balance bearings and I premix the ski at 50:1........

    So cycl 1 and 3 in a stock motor get fuel and oil from the pump and from the balance bearing oil...cycl 2 just strictly from the pump...

    So with my setup all 3 cycl will be getting 50:1 (yes at idle there is a little bit of smoke) but 1 and 3 will be getting extra oil lets say this knocks ratio down to 40:1.

    Cycl 1 40:1
    Cycl 2 50:1
    Cycl 3 40:1

    The 40:1 value it completely arbitrary (I am working on an actual value); but for conversation purposes lets say its accurate. I have seen people run 40:1, 50:1; and our manual says the ski runs 60:1 at full throttle with the pump hooked up.

    So the question is am I being totally stupid and should I shut up? Or is it bad to run different mixtures in diff cyclinders?
    I understand a 40:1 mix is not optimal for performance but reliability stand point?

    Im just trying to learn more about this hobby and my machine.

    Thanks in advance!!!

  2. #2
    Anyone know the fuel flow rate for the carbs I cant seem to find it in the manual? I want to see if I can get some numbers together...

    --And i know some of people running stock injection also run about 100:1 in the tank for safe measure (these skis are modified of course) but just to add to my own mental dilemma this would net about a 36:1 gas to fuel (using the 100:1 from the tank and the 60:1 that manual states the ski runs at at full throttle)

    Ok here goes nothing im not a mathematician either.....

    ski burns 13.3 gal per hour (full throttle)= 4.428 gal per cyclinder per hour
    Oil pump should yeild a difference (from the manual) of 2.66ml from cylinder 1 and 3 compared to cylinder 2 at 400ml; this difference equals 1.34ml per 3 minutes.
    1.34/3 equals .446ml which equals .015 oz per minute times by 60min= .9 fl oz. per hour

    So at cylinder 1 and 3 we have 4.428 gal per hour gas and .9 fl oz. per hour which equals a rough estimate of of 625:1 ratio per hour of extra oil coming in.

    Taking the 625:1 ratio and adding it to the 50:1 from the tank we come up with

    Cyl 1: 625:1 +50:1
    Cyl 2: 50:1
    Cyl 3: 625:1 +50:1

    Let me know if my bordem has gotten the best of me and if I over looked anything or am completely off base with this thinking.... if this is true 625:1 can seem like it could alter performance that much.

  3. #3
    The numbers for the oil im getting is the difference between what the oil pump puts out to cyl 2 as compared to what is compensates for at cyl 1 and 3 for the oil that cyl 1 and 3 consume from the balance bearings if anyone is confused....I know I was when I re-read my post haha

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