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  1. K

    Mercruiser 3.7/470 Overheat Problem

    The head comes off pretty easy, however there are some bolts under the intake manifold going into the head which cannot be seen from the top. Also be sure to tell the machine shop to replace the air injection plugs in the front and rear of the head.
  2. K

    Mercruiser 3.7/470 Overheat Problem

    You still should pull the head. There are 2 types of 470 head gaskets, the ones that are leaking and the ones that haven’t started leaking yet.
  3. K

    5.0GXi Starter Replacement

    You may need new bolts for the PMGR. Well worth the effort as they also draw less current than the original heavy Delco.
  4. K

    1987 Merc 180 (“470” 3.7 litre) won’t idle

    That wire is being fed by the ignition switch in the “run” mode. After the engine starts the “bypass” circuit is no longer feeding 12 volts to the coil. The voltage at the coil is now provided by the ignition switch. Since the purple/yellow wire is connected to the + or Bat side of the coil...
  5. K

    1976 888 (MC-1) Trim/Tilt pump/line leak

    You can match up the “O” rings at any auto/hardware store. Be sure to put a straight edge across the mounting holes on the mating surface. You will see the plate is bowed, so just take a file or run it over a belt sander to flatten it out. Stick the “O” rings to the bottom of the pump with...
  6. K

    torque or angle torque

    All the big box auto stores have them.
  7. K

    Flywheel housing for 280 outdrive and newer 5.7

    If the hole is not drilled do not panic. I have drilled and tapped the extra inboard hole. With the engine on a stand flip it over, mount the 2 bolt starter using the outboard hole tightly so it will not move. Square up the starter lining it up with the rear block surface. With a piece of...
  8. K

    1987 Merc 180 (“470” 3.7 litre) won’t idle

    A compression test should be done on the engine in question.
  9. K

    Mercruiser 3.7/470 Overheat Problem

    There is 1 other thing you need to check. With the engine running on a flushout or in the water remove the hose from the drive pump and try to stop the flow with your hand. You should not be able to, If you can stop it then the plastic water pocket cover in the upper section of the drive shaft...
  10. K

    Mercruiser 3.7/470 Overheat Problem

    You have a head gasket leak. What you are describing is a common problem. Have a valve job done and get the head resurfaced. You will never see where the gasket is leaking. The cylinders have no lateral support and over time they tend to “walk” from side to side. I guaranty changing the head...
  11. K

    Mercruiser 165 6cyl inline dies when boat is in the water

    In that case try the 6 gallon outboard method. This is a tried and true way to locate fuel problems, or rule it out.
  12. K

    Timing mod: running or not running engine

    For me to keep from having to turn on & off the water & jumping in and out the boat I also set the dwell like SD. I then attach the spark plugs to the wires and leave them grounded on the manifold, spin the engine to set the timing.
  13. K

    Mercruiser 165 6cyl inline dies when boat is in the water

    In post#4 you said that with an electric fuel pump the engine runs. Am I wrong the way I am interpreting that? Have you ever tried by passing the tank by using an outboard tank directly to the fuel pump with the primer bulb? If your engine is running out of fuel you may have a crack in the...
  14. K

    Mercruiser 3.0 won't "lock in"

    If the splines completely went away there has to be a alignment problem. sierra #18-2321 looks like the coupler that you need Mercruiser # 12632A6 sierra#18-4442 alinement tool. Every Mercruiser owner needs this.
  15. K

    Mercruiser 3.0 won't "lock in"

    A very good chance the vertical shaft is the problem.
  16. K

    Alignment adjustment, witness marks

    If you have a small bottle jack or an overhead hoist loosen the mounts and either under the harmonic balancer with the jack or with the hoist raise and lower the front of the engine. This makes getting alignment easy and fast. Then set the mounts, quite often the stringers are never the same...
  17. K

    How would a compromised bellows sink the boat?

    The 2 “O “ rings on the driveshaft are there to grip the gimbal bearing. There is usually a 1/4” breather hole at the 12 o clock position above the driveshaft. With a torn bellows water can really get into the bilge.
  18. K

    Mercruiser 3.0 won't "lock in"

    There is a tutorial on this site on how to adjust the shift cable.
  19. K

    Mercruiser 409 engine severe vibration issue

    It has to be a flywheel problem. And maybe the wrong harmonic balancer.
  20. K

    1996 OMC Cobra (Ford 302 / VolvoSX collaboration) sometimes runs hot

    Remove the hose from the drive to the raw water pump. Try reverse flowing that hose into the drive with the drive up, look at the plastic through transom fitting, it could be cracked. Was this happening before the rebuild? The other problem could be a leaking head gasket which builds enough...
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