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  1. Lou C

    4.3 Valve seals

    I can't imagine they are marine specific. The heads are just plain old Chevy V6 heads. Take the casting # off the head and go to a GM dealer! Merc loves to charge an absurd surcharge for a part GM made and is available in the aftermarket as well. Do not buy any GM engine parts from either Merc...
  2. Lou C

    Servicing my trailer bearings

    That's a good deal for brand new!
  3. Lou C

    5.0 Merc Compression Readings

    that's higher than normal, was there any sign of water in the cylinders? that's a cause of high compression test results. other causes of high compression test results on what's not a high compression engine: faulty gauge carbon build up in the combustion chambers normal is about 150-170 or...
  4. Lou C

    Starting engines with jump box & dead house batteries

    I think it’s alway safer for your alternator to discuss nnect the battery and put it on a charger to see if it comes back up to at least 75%. If it won’t, buy a new battery!
  5. Lou C

    2018 Mercury 40 EFI – rhythmic RPM surging at WOT after 5 minutes – video

    Another possible cause might be a clogged screen (if it has one) on the fuel tank pick up tube. Also look in the stickies, there is a nice section on troubleshooting your boat's fuel system that goes through all the pressure tests, vacuum tests, clear hose test, etc. All good to check and rule...
  6. Lou C

    Milky oil

    People who do that haven’t had the experience of doing the same dang job twice with their own hands lol!
  7. Lou C

    Milky oil

    Those will come apart when you disassemble but my experience is they rarely leak. But I guess you gotta do what he wants but with the disclaimer that’s only one of several possible leak points
  8. Lou C

    Starting engines with jump box & dead house batteries

    No but it means that it has to be sized in terms of amp capacity for what loads will be put on it, or else the batteries will never be fully charged. Standard old school alternators for inboards are like only rated @ 55 Amps! Later models are rated for more but you need to take the whole...
  9. Lou C

    Milky oil

    They actually look pretty good. Are the fire rings totally intact? If so it makes it even more important to have the heads checked because I don’t see a smoking gun yet.
  10. Lou C

    Milky oil

    water got in somehow, do you still have the old HGs, post up a pic. Given the labor to R+R and have to do it twice, explain to him it's smart to have the heads at least checked for cracks. They don't have to mill them as long as they are flat and level to no more than .003" variation. A minor...
  11. Lou C

    Milky oil

    hard to say, but that could also just be the HG leaking a bit in that spot. That is where they crack though, in the cam valley. isn't there some kind of dye you can paint on to check for cracks? check the block deck very carefully after cleaning off the remnants of the HGs. looking at your pix...
  12. Lou C

    Milky oil

    I was thinking the same thing, no pressurized air from the cooling system should wind up in the intake.
  13. Lou C

    Milky oil

    You made a lot of progress there, report back after you find out from the machine shop if they are good or not. Did the head gaskets show any signs of burning or separation? Mine definitely did. After a few run/check for water/drain cycles I figured out what was happening. I would run it on...
  14. Lou C

    Starting engines with jump box & dead house batteries

    ARCO has some good tech info on their site about alternators, one thing I recall from reading it is that alternators are more of a battery maintainer than a battery charger and as Scott said, they don't charge much at idle. In fact, even with a healthy battery, if it's even just at about 50%...
  15. Lou C

    Adding antifreeze

    it is really surprising the extent that mercruiser went to just to avoid installing a half closed cooling system. When my brother had a late model merc, (2020 4.5 V6 in a Chapparal) I told him about this, as the boat ages and is used more sooner or later someone (not I that's for sure) is going...
  16. Lou C

    Servicing my trailer bearings

    stainless steel isn't rust proof it just stains-less! I think if you changed your brake fluid every 3-5 years (some trailer manufacturers advise this) and actuate the brakes at least once or 2x a month when it's in storage, I think your calipers can last longer.
  17. Lou C

    Milky oil

    Looks like a Pre-Vortec 12 bolt intake, those don't tend to leak as much as the Vortecs, which needed the updated improved intake gaskets.
  18. Lou C

    Milky oil

    When I had my water in the oil problem, I figured out a way to run the engine on the water hose briefly to check for combustion gas getting into the cooling water. At first I didn't see anything but after running it enough to warm up sure enough I saw bubbles, a sure sign of a blown head gasket...
  19. Lou C

    Servicing my trailer bearings

    The piston might be aluminum, if so, keep in mind you have dissimilar metals, and brake fluid absorbs water. I would replace it. I use 12" drum brakes on my trailer, and I keep a set or 2 of wheel cylinders in the garage in case one seizes up. I also have a pair of complete backing plates as...
  20. Lou C

    starter concern

    Anytime a marine engine gives problems with cranking the two things to check first are battery/terminals & spark plugs for water.
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