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Recent content by makomark

  1. makomark

    1968 omc 120hp dual carbs

    I don't have a definitive (independent) source but can tell you the stern drive community got rid of the "top plate" manifolds on the GM inline engines because they were prone to warping...and that would lean to a lean mixture...which leads to engine rebuild/replacement....the replacements were...
  2. makomark

    Replacing coolant - Can't open bleed valve

    as long as the fill neck on the HX is the highest point in the system, then yes, the air will eventually make it to the HX... you can also tell that the air is gone when the coolant level stays constant after a run...in other words, check it cold, run the engine and let it sit until cold again...
  3. makomark

    Replacing coolant - Can't open bleed valve

    I'd suggest filling the HX, running the engine until the T-stat opens and then shutting it off...and then cool until the T-stat closes...run thru a few cycles and the vast majority of the air in the cooling system should be purged. If you have the overflow (degas) bottle and the cap is in good...
  4. makomark

    no start after rebuild (x2)

    sounds like you have pulled the heads already - what did you find?
  5. makomark

    1968 omc 120hp dual carbs

    The MERCARBs are younger cousins to the Rochester 2G's...the smallest 2G will flow ~ 275CFM so that would the preferred configuration. The left side works like the right side when everything is correct...in either.
  6. makomark

    Gauge HELP

    Never dealt with that brand; the OEM should have installation details readily available. that said, its common to use one mold for the housing so have 'extras' in very possible (on the voltmeter). I - switched IGNITION (the +12VDC to make the gauge work) S - SENDER for pressure and...
  7. makomark

    Gauge HELP

    ok...what's the question(s)???
  8. makomark

    no start after rebuild (x2)

    Probably be a good idea to identify what engines you have...assumptions can lead to disastrous results... The improvement after adding the oil really isn't definitive as you have a zero hour rebuild...ie the rings likely have not seated. Very likely the bulk of the 'leak is due to the valves -...
  9. makomark

    no start after rebuild (x2)

    On the engine w/ 150PSI of compression, if it has plenty of spark and fuel in the carb, I'd start by making sure the fuel is good...no joy w/ ether suggests the timing is way out...I'd be inclined to check the initial timing before doing anything else. on the engine with 60PSI of compression...
  10. makomark

    Crusader 454 xli no fuel pump power - looking for some diagnostic help

    its a SPDT switch...the common terminal feeds the fuel pump, the red/yel supplies current to the fuel pump when cranking(N.C. terminal) and the purple wire supplies current with the engine running (N.O terminal)...
  11. makomark

    Mysterious Milky Oil - Not Risers...

    towards the end of the first video, it looks pretty clear that the water is flowing out of the head just behind the valve guide...that suggests the head is cracked and needs to be replaced.... As Kghost suggests, pressure testing the block with show most of the issues
  12. makomark

    Alpha One Lower Unit

    the casting breaks as it isn't thick enough to handle the load the 'fin' puts on it when the boat is moving...
  13. makomark

    Transom Rebuild Question.

    Judging by the generous bead of silicone around the transom housing, I'd say there has been an ongoing leak for a while. It is hard to tell exactly what you have from the pictures. Why do you feel the need to rebuild the transom? Typically, the smaller I/O hulls have a plywood transom with an...
  14. makomark

    How to edit post? Or even contact admins?

    you get about five minutes once you hit the POST button and then its locked... If its a major foobar, you can ask one of the admins to change it for you...
  15. makomark

    Om636 does not start

    sounds like it is slow cranking over...I'd be inclined to start with a good cleaning of the battery cables and a load test on the battery...I've seen cases where, while cranking, the fuel control will close inhibiting starting....so check the voltage at the solenoid while cranking....
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