Cat C-12

Discussion in 'Downeast Engine Room' started by Derek brown, Jul 11, 2019 at 3:03 PM.

  1. Derek brown

    Derek brown Member

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    So I have a single in my charter boat with 16k hours that now won't start without ether. Once it gets going with ether she runs like a top. No smoke and good power. We just sea trialed with the mechanic and the blow by showed 3000 when he said it should read max 1000. They are recommending over haul. I'd rather wait until the season is over and keep using the ether until then. How silly is my thinking?
     
  2. GLA

    GLA Senior Member

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    my only concern is that it could run away
    then you need a good air shut off to stop it, or boom
     
    GLA,
  3. Derek brown

    Derek brown Member

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    I have an external fuel shutoff valve..We didn't do a compression test. Ran out of time. 14hr charter tomorrow.
     
  4. Gurryman

    Gurryman Captain

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    shutting off the fuel wont stop a runaway. It will run until it sucks and burns all the oil out of the crankcase. Only way to stop it is to block the air intake.
     
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  5. Derek brown

    Derek brown Member

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    ok thanks. I'll bring hearing protection to damn the air intake
     
  6. Toolate

    Toolate Captain

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    Curious what are the units for that 3000 reading? Not cfm (!!!) lol.
     
  7. ARC

    ARC Senior Member

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    I understand you wanting to wait for the season to be over. but if I chartered you and your boat I would expect a safe boat. A boat that needs to start on a can of ether does not meet that requirement.
     
    ARC,
  8. WoundUpMarine

    WoundUpMarine Captain

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    Are you burning any oil? How much ether are you talking about, a small quick shot or a decent amount of ether? I know a lot of skidders had ether "buttons" on them stock, so even though ether isn't recommended at all, it isnt the end of the world. Are you using it just for the first start of the day or every time you have to start it? An engine "running away" from broken or worn rings is rare and personally wouldn't be a concern of mine.
     
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  9. Derek brown

    Derek brown Member

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    It will start with two sprays onto the air filter. The blow by is 481ft3/hr at 75% load. CAT specs is 240ft/3hr at that load. I have been using the ether for 2 weeks fishing daily now while waiting on the mechanic. We thought it had something to do with a sensor or electrical something.
    I leave the engine running during the entire charter. It uses some oil, but not a disturbing amount. I'd say one gallon per 100gallons of fuel. I'd be concerned if amounts of smoke was coming out of the back, but it runs clean.
     
  10. Joshbel02

    Joshbel02 Senior Member

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    Run it and tell us what happens...maybe it will get u by or you will some sort of story time for us...I’d personally give her what she wants
     
  11. Toolate

    Toolate Captain

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    Interesting. Blow by specs are hard to find as far as I can tell anyway. Would love to see them for my 3116.

    The “run away” concept is an interesting one to contemplate. Imagining asphyxiating either of my engines running at WOT (or more) doesn’t sound fun so good to have a plan anyway! Personally I would prob run it. Summer is short. Make money and enjoy.
     
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  12. Genius

    Genius Captain

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    What Hp C12 do you have? What WOT can you achieve? What RPM do you cruise at?

    We have two of these engines rated at 450 hp in one of our boats that we run.
     
  13. traditions

    traditions Captain

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    The only engines I remember running on base oil were GM 2 strokes. They had air dams built into the blower housing with spring tension. Where does your crank vent go? Run it out the top of the house, with no low spots so it has positive flow back to the valve cover. I have seen 300 deeres running enough base pressure to fill a gallon jug with oil, and they keep on going. 16,000 hours isn't a real lot of hours,seen many diesels with 30,000. Does it puff vapor out the oil fill, or is it a steady flow of pressure? Steady flow would be best, as if its puffing its probably a cracked piston or ring. Some say run 30 weight for a cycle, reseat the rings, not sure if it works or not. Some diesels get glazed cylinders from a lot of idleing, causing ring blow by.
     
  14. Derek brown

    Derek brown Member

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    14 hr charter yesterday. All is well. Back on a 10hr today. This motor is set at 705hp, but we have a 2.5/1 gear where we need a 1.5/1. Can't swing big enough wheel. So we typically cruise at 2000rpm which is a 55% engine load.At 2390 its about 78% engine load. I've been running this motor for 15 years now. I normally shut down at each fish spot and never really idle. Now we have to let her idle all day. I don't want customers seeing the ether trick. It has a crank case ventilator at the top of the engine.
     

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