OMC Stringer Problem

Discussion in 'Sterndrives' started by CarbonFootprint, Nov 26, 2009.

  1. CarbonFootprint
    Joined: Nov 2009
    Posts: 60
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    Hello,

    I'm rather hoping somebody can offer some advice or words or wisdom here...

    About a year ago, I bought a Shetland 570 with an inboard OMC sterndrive setup. On the first trip out, the engine started billowing black smoke and everything stopped - it turned out it had overheated and seized.

    I had the engine rebuilt and, this week, finally finished rewiring it all and decided to test the electrics. I was fairly happy to find the battery still had enough charge to lower the drive leg, but not quite as happy to discover oil pouring out of the water intake just above the prop shaft...

    This is the first time I've lowered the leg since the stupid thing blew up, so I assume this is symptomatic of the reason why. I also assume that a seal has gone on the drive shaft and the oil had pooled around the impellor, waiting for the day I lowered the leg and it could all drain out...

    The sterdrive is a Stringer 400/800 model number 980701, serial number 120B 4290 - it is, indeed, the same sterndrive as Noah fitted to the Ark (I'm reliably informed). On the off-chance that somebody out there knows how these things work, I'd be very interested to know what they think has happened and, to the nearest power of ten, how much it's likely to cost to repair.

    Any thoughts, comments or sage stroking of beards will be much appreciated,

    Many thanks,

    Paul
     
  2. gonzo
    Joined: Aug 2002
    Posts: 15,818
    Likes: 1,222, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    First, that model was not fitted to the Ark as the myth has it, but to the Ark's tender. Second, If there is oil in the water pump, likely there is water in the oil. Take the drain plug off and see. Also, check out this site
    http://www.sterndrive.info/
     
  3. CarbonFootprint
    Joined: Nov 2009
    Posts: 60
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    :)

    Thanks for that - admittedly, I haven't yet checked the oil (or what's left of it) in the leg, as night had decended upon me by that point and I haven't built up the mental fortitude to go back yet...

    How would water get into the oil, other than by a failure in/near the impellor?

    Thanks for your help,

    Paul

    (I have posted this same Q to sterndrive.info but not much by way of conversation seems to happen on that site...)
     
  4. gonzo
    Joined: Aug 2002
    Posts: 15,818
    Likes: 1,222, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The impeller is on the top back of the drive and is driven by a shaft attached to the gear. There is a double seal that keeps the water out and the oil in. i am working in London now and can relate to the short daylight. You got it worse.
     
  5. CDK
    Joined: Aug 2007
    Posts: 3,324
    Likes: 148, Points: 63, Legacy Rep: 1819
    Location: Adriatic sea

    CDK retired engineer

    There is also an upper gearbox. When reassembling a drive, some people poke around with the drive shaft to get it into the hole and while doing so damage the upper seal.
    It could explain the oil flowing from the water intake.
    Water will have replaced the lost oil and may have done damage, but you may also be lucky and cure it with just a new seal and some fresh oil.
     
  6. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    The problem(s) will be obvious to an experienced mechanic. Pull the drive off, with luck you'll only need a new transom kit, which should be complete to prevent any additional issues in the future. If you don't know how long it's been since previous service, then just bite the bullet and get a new set of seals, bearing, grease the U joints, R & R the hoses and bellows, Check the shift cable and rod adjustments, make the upgrade to upgrade the shift cable if the recall wasn't preformed, etc., etc., etc. Maybe the distribution block and trim hoses too, because you can't change these without pulling the drive again. Of course new oil and impeller. All this would be very familiar to a person experienced with the OMC Stinger. It's not rocket science, but some familiarity is necessary. Buy the repair manual and have a go, though some of this is usually beyond the shade tree guy, because they just don't have the tools or experience.
     
  7. CarbonFootprint
    Joined: Nov 2009
    Posts: 60
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    Hello,

    thanks for your advice.

    A broken upper seal seems most likely to me considering what you say - the previous owner told me he'd recently replaced the impellor before I bought the boat, so it seems feasible that he made a mess of putting the shaft back in and damaged the seal as he did so.

    It's being able to identify the problem that makes me reticent about stripping the leg myself - I'd imagine, to my untrained eye, the inner workings of the leg are going to look fine, despite whatever damage has gone on within.

    I've actually managed to find somebody who's willing to strip the leg and repair it if possible, so all(!) I need to do now is remove it from the rest of the drive.

    Thanks for your help,

    Paul
     
  8. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 491, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    It may not be necessary to break down the upper and lower gear cases. In fact, I would strongly recommend you not do this or let a "buddy" do this. There are just too many special tools and precautions you need.

    Remove the drive and if things aren't obvious . . ., remove the pump if things aren't obvious . . . I'll bet they are obvious and new transom kit will solve the issue(s). Again while you're there, replace what you can't get at, when the drive is in place.
     
  9. gonzo
    Joined: Aug 2002
    Posts: 15,818
    Likes: 1,222, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    The easy way to test it is to put air pressure in it, about 10PSI. Submerge the drive in a water tank or close lake and look for the leaks.
     
  10. CarbonFootprint
    Joined: Nov 2009
    Posts: 60
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    That's what these chaps willing to have a look at it for me said they'd do.

    I started taking the leg off yesterday...in the rain...in the dark :(

    I managed to shear the heads of three end-cap bolts - I barely touched them! Having got the end-caps off, the next job is removing the pivot end-caps (helpful, having two things called end-caps in the manual - a bit confusing steps two and three both being "remove the four end-cap bolts"!) and then lifting the leg away from the rest of the drive.

    I've found barnacles which are practically fossilized in the pivot housings and encrusted salt like you wouldn't believe! I think I'm edging from "repair" to "restoration" here :)

    One thing I was wondering, though (probably becuase I haven't read the manual thoroughly enough) is why you have to remove the leg to detach the lower housing from the upper housing? It looks to me like there are four bolts that hold the two halves together and, if you removed them, you'd have direct access to the pump impellor. There's probably a very good reason - I just wondered if anybody knew what it was?

    Thanks,

    Paul
     
  11. gonzo
    Joined: Aug 2002
    Posts: 15,818
    Likes: 1,222, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    You don't need to remove the whole thing just to work on the impeller.
     
  12. CarbonFootprint
    Joined: Nov 2009
    Posts: 60
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    That's what it looks like to me, too, but the manual insists you take the leg off the drive...
     
  13. gonzo
    Joined: Aug 2002
    Posts: 15,818
    Likes: 1,222, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    It is a good idea to do a complete service anyway.
     
  14. CarbonFootprint
    Joined: Nov 2009
    Posts: 60
    Likes: 0, Points: 6, Legacy Rep: 10
    Location: Northern Scotland

    CarbonFootprint Ill-Advised Boat Modifier

    Considering the state the pivots etc are in, I'll go with that!
     

  15. powerabout
    Joined: Nov 2007
    Posts: 2,931
    Likes: 66, Points: 48, Legacy Rep: 719
    Location: Melbourne/Singapore/Italy

    powerabout Senior Member

    the 400/800water pump is under the top gear housing not on the back like the later models ( which are not called stringers as they transom mount like a Merc) so you only have to remove the lower unit.

    Some of the posts above are referring to later drives

    The OMC stringer in the ark was a v4 two stroke with electric shift

    PS You did mention 'oil leaking from the water intake above the prop'? Is yours electric shift?
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.