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NEED INPUT FAST on merc I/O

Discussion in 'Boats and Motors' started by FISHIN 2, Jul 23, 2007.

  1. Need some opinions on a I/O problem. When putting boat in gear, prop will push boat at LOW SPEED, when throttling up, as starting to push hard, seems like prop is slipping. We tightened prop nut as tight as feasable, put back in water and it still slips, just as power is coming up. We thought it might be the prop, pulled that prop, put on spare and the same thing, ok, thought maybe another bad prop. Took prop off a good boat, same thing. What's causing the slippage ? Ok at low rpm's, try to power up and seems to slip. Is their a gimble clutch or any type clutch to check out ? Need some input, anyone . Thanks in advance, Mike
     
  2. KaGee

    KaGee Monkeywrench Staff Member

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    There is only one other thing in the drive-line I can think of... your engine coupler. But I would think that would strip out very fast. Any burnt rubber smells in the doghouse?

    You should visit HERE
    There are a couple of Merc Pros that can steer you right.
     

  3. Didn't give it a chance to slip much. As soon as it slips, I shut the throttle down. Will push the boat ok with low rpm's, just slips when you power up. Actually, starts to power up, then motor rpm's will race as if prop spins. Never really gave it a chance to slip more that a couple secs. Mike

    ps. thanks for the site also!
     
  4. sounds like a prop hub to me...if you have a spare prop put it on and try it
     
  5. We tried 3 props and still had the same results. Seems to be a coupler issue, that's not what we wanted to hear. Mike
     
  6. KaGee

    KaGee Monkeywrench Staff Member

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    Sorry to hear that. It's a PITA to pull the engine, but that's about the only way to change the coupler out. Hopefully everything else in the drive-line is OK.

    Engine to drive alignment is crucial in all Mercruisers, Volvos and OMC Cobras. Mercruiser reccomended maintenance calls for the drive to be pulled every spring and the alignment checked along with a few other things in the driveline.
     
  7. Before i pulled a motor, I'd pull bearing cap on top of upper unit [3in. square 4 bolts] . You can see top gear , make sure there ok . Then I'd put unit in gear and move prop by hand, might learn something-or not.
     
  8. Wonder if I pulled that cap, would I need a new gasket ? Might be worth checking out before goin back to the water. Thanks, Mike;)
     
  9. A forum that has been very helpful for me when i have a boat repair problem is http://www.boatered.com. I list my problem under "Ask The Captain" or "Engines, Electric, Plumbing, etc." and I usually get quick and knowledgeable responses.
     
  10. KaGee

    KaGee Monkeywrench Staff Member

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    Note: Gears do not "slip". Drain the oil and inspect the plug for shavings if you are concerned about the drive internals. There will always a few and I mean very few, small shavings from normal wear. A bunch of shavings indicate a problem somewhere. But, like I said, gears do not slip... they clunk and grind to a stop.
     
  11. I agree about the gears. Everything sounds smooth, no grinding or clunking.
    Pulled motor and replaced coupler. Found out wrong prop was on boat, had 21, switched to a 19, no need for speed, power is more important. We'll give her a shot in a couple weekends. Just want to wait till the BIGGER perch turn on. Got our limit for 4 guys last time, just poundage was way down. Might try fishing more towards the central basin if we get some favorable reports. Never fished over that way for perch, hear they're bigger over that way, just no place to hide in rough weather. :eek: Mike
     
  12. KaGee

    KaGee Monkeywrench Staff Member

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    I hope you checked the drive alignment after re-installation of the motor.
     
  13. KaGee

    KaGee Monkeywrench Staff Member

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    I found Boater Ed to be a bunch snobish, yacht-clubber know it alls mostly from NY and NJ. And you now have to PAY $20 a year to get access to the mechanical "how to" information. (Spending nearly $800 at their sister site BOATFIX meant nothing to them :mad: )

    Iboatsdotcom is made up of regular guys just like here @ OGF. There are many Pros in the "HELP" forums as well as experienced backyard hackers that share their knowledge for FREE!

    Iboats has triple the members of boatered, nearly 100,000 now.