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  1. Lou C

    OMC Cobra 4.3?

  2. Lou C

    OMC Cobra 4.3?

    I always used at least 89 in mine and the gas docks local to me sell only 93 octane. With the dog clutch Cobra drive you want your idle to be not more than 600 in the water. In order for the drive to shift to neutral you need it to idle that low so the ESA system can lower it down to 450 rpm...
  3. Lou C

    OMC Cobra 4.3?

    In the pic I had just installed a pair of remanufactured cyl heads since I had a bad overheat a few years before that and the head gaskets blew necessitating the repair. When I had the old heads checked there were cracks so replacement made more sense. In boats you must use the marine version of...
  4. Lou C

    Gas vapor out the secondaries at WOT

    Break out your impact gun for the head bolts and those intake manifolds can get really stuck on. I was able to get the head bolts out easily but the baked on old intake gaskets were like kryptonite
  5. Lou C

    Stickies on Winterizing 3.0 cobra

  6. Lou C

    Stickies on Winterizing 3.0 cobra

    OMC used a brass drain valve that you should be able to find. In addition to the drain on the exhaust manifold and on the engine you have to disconnect the bottom end of the big hose connecting the front water pump to the thermostat housing. There are 3 plugs on the pivot housing you have to...
  7. Lou C

    Gas vapor out the secondaries at WOT

    You can do a cyl leak down test before taking anything apart. If the leakage is from the valves you can pull the heads with the engine in the boat but if it’s rings then the motor is coming out.
  8. Lou C

    Penta 4.3 Overheating

    Great tip! also if you can find it, see if you can find and print out a document called "volvo penta overheat diagnosis" it covers this and other points you want to make sure to check out. One other thing, a poster on here had the water tube rot out that allows water to flow from the lower...
  9. Lou C

    OMC Cobra 4.3?

    You're actually lucky you have electronic ignition because the way that boat is set up the distributor is UNDER the area where the sun pad hinge is. I'd don't know how you'd access it even! The GM V6 distributor is at the rear of the engine like every other Chevy small block V8 or V6. On my boat...
  10. Lou C

    Exhaust corrosion

    Prob wondering if Yamaha ever fixed the corrosion issue. You’ll find many threads on this on the hull truth boating forum.
  11. Lou C

    OMC Cobra 4.3?

    You don’t have bat wings so yours must be a 1991 or newer. The bat wing was a one piece manifold/elbow unit used from 1985-1990. And it probably had the OMC electronic ignition which may have been converted to a Petronix due to a lack of parts.
  12. Lou C

    Exhaust corrosion

    If you look over at the Hull Truth there are reports of this on F150s as new as 2014. I’m not sure they actually solved it. Probably varies by model.
  13. Lou C

    Penta 4.3 Overheating

    you want your temp to look like this....
  14. Lou C

    Penta 4.3 Overheating

    If your impeller was shredded the bits probably are in the thermostat housing, because that's the next place along the water flow route. You'll have to pull the housing (get a new gasket), dig out the rubber ring that holds the stat in the housing, test the stat in a pot of hot water (should...
  15. Lou C

    If you need to replace your Cobra power steering actuator here are a few tips…

    Finished up today, bled the air out, just kept running it stopping every couple of min to check the fluid level, took about 15-20 min of running to get it all out, stopped when the level in the reservoir stabilized. This is one job I really hope to only have to do ONCE!
  16. Lou C

    Antifreeze circulation through engine

    PS west marine -100 has corrosion inhibitors Sierra PG antifreeze is good enough to use as a coolant. Probably the best of all, for corrosion protection. It is not easy to find though.
  17. Lou C

    Antifreeze circulation through engine

    1) freezing water ONLY causes damage when it can't expand, so if there is a little water left there will be no harm done. 2) If you read Mercruiser's shop manual they say to: a)drain to prevent freeze damage b)back fill with AF to reduce corrosion if you drain the AF out, after doing step b you...
  18. Lou C

    What are these holes?

    Correct and if you DON’T see water coming out rod em out with a thin wire
  19. Lou C

    OMC 5.7 Questions

    I would tell you to avoid ANY old boat with a I/O power train they are very high maintenance regardless of whether it’s Merc, Volvo or OMC. You’re best off buying newer and 4 stroke outboard powered. For the record I have had beyond excellent service from my 1988 OMC 4.3 Cobra. The first couple...
  20. Lou C

    If you need to replace your Cobra power steering actuator here are a few tips…

    Got the new unit in today made sure to grease all the cotter pins if I ever have to remove it in the future.
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