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  1. jimmbo

    40hp Dead Top Cylinder

    "Very little Suction"... Was Fuel getting sprayed back on your Hand when you covered the Carb? Are the Oil Streaks on the Block, along the Crankcase Seam, or coming down from under the Flywheel?
  2. jimmbo

    Prop size and pitch

    If you are only getting 3200rpm at WOT, I don't think there a Prop with a low enough Pitch to to even 5000rpm. 1800rpm shy, means you would need an 8" or 9" Pitch, As mentioned, you need to verify the Tach My 78 90hp with a 17, turning 4800 was getting 38mph. WOT Range 4500-5000 My 84 115hp...
  3. jimmbo

    Motor turning to the left

    I assume your motor is a 4 stroke. If not a model# would be very helpful There should be a Friction Adjustment on the Swivel Bracket #23
  4. jimmbo

    40hp Dead Top Cylinder

    When you put your hand over the top Carb, did you feel any Suction? A bad Intake Manifold to Block Gasket can prevent Crankcase Inhalation/Compression, as can a bad/worn Upper Crankshaft Seal. Look on the outside of the Block. Is there any signs of Oil running down the Outside?
  5. jimmbo

    Any saving the engine? I’m devastated

    It wouldn't hurt if you unscrewed them, cleaned the area, hit them with some Deox. Of course there is the risk of Damaging the Wire and/or Connector Ends... The Motor is a 74 and thus 50 yrs old
  6. jimmbo

    What do these 2 rubber hoses go to?

    Maybe a Previous Owner needed an Extremely Stealthy Motor and the Idle Relief was giving him/her away... I have seen many Motors butchered over the Years, and can count on less than One Hand, an actual Improvement over Stock.
  7. jimmbo

    Any saving the engine? I’m devastated

    I guess if the OP is willing to buy a Starter in a yr or so, and looks forward to having to Rope Start the Motor, or Paddle home, he doesn't Need to take it apart, clean and lube it
  8. jimmbo

    Any saving the engine? I’m devastated

    The questioning about it running when it got wet, is because engines that are running can suffer very serious damage, as Water is not Compressible, and if enough were to get into the Cylinder, the Engine would literally stop Instantly, even at 5000 Rpm. Bent/Broken Con Rods, Crankshafts, Pistons...
  9. jimmbo

    4.3 Carb…What’s That Hose?

    You will likely find that the other end of that hose goes to the Fuel Pump, and is there to prevent any Fuel from a leaking Pump Diaphragm, spilling into the Bilge, by diverting it to the Carb. By now the Hose is likely stiff and inflexible, and should be replaced. Again, getting the Hose from...
  10. jimmbo

    Any saving the engine? I’m devastated

    Great to hear Did any water drain from the Carb Bowls, or spray out the Spark Plug Holes? You have to run it for quite a while, to make sure all the Water has either been thrown out of the Bearings, or has evaporated. The Lower Crank Shaft Bearing is the most Vulnerable as the Water can't drop...
  11. jimmbo

    Any saving the engine? I’m devastated

    And keep it running for at least an hour Spraying some Engine Cleaner(BRP) or PowerTune(Merc) into the Carbs when running, will help flush out Water from the Bearings,
  12. jimmbo

    Any saving the engine? I’m devastated

    #36 is the Drain Screw of the Carb Bowl
  13. jimmbo

    1977 merc 150 outboard bogs at WOT

    To get the revs up to 5800, a 17" is likely the Pitch that is going to be needed. The 150 runs great from 4000 to 5800, but below 4000, it can be an unhappy camper.
  14. jimmbo

    1977 merc 150 outboard bogs at WOT

    First thing is a Compression Test Next, does the Ignition System, provide a Spark strong enough to Jump a 3/8" Gap at all Plug Wires? Did you set the Floats correctly? After you replaced the Carbs, did you verify the Link and Sync between the Spark Advance and Carbs, and adjust to spec if...
  15. jimmbo

    video of my motor idling

    That is why the Correct Service Manual is Important. But the basis is, the timing is required to be at a Specific Point, where the Carb(s) are still closed, but the slightest advance of the Timing, will be the start of the Carb opening, ever so slightly. And the all Timing Advance will also be...
  16. jimmbo

    OK for the spark plug gap to be slightly off from recommended?

    The NGKs that came in my 84 115 when new, were still in it in 1998, with 700hrs on them, when I traded the Boat and Motor on a new one
  17. jimmbo

    blue -v- brown band

    That Cowl Decal was used1980 thru 1983
  18. jimmbo

    blue -v- brown band

    1983 and older 115s would have the Pump in the Boat TNT That is one of the Joys of Mercs for many yrs, as the variations of the Decals were often slight, over the years.
  19. jimmbo

    blue -v- brown band

    Brown was used in 1984 and 85. They dropped the Compression a bit after 83 1982 was the Year Mercury started Prop Rating all 6 cylinder engines However some late 81s might be Prop Rated Any 115 with a Serial Number up to and including 5050763 would be Crank Rated 5050764 and above would be Prop...
  20. jimmbo

    85hp 3 cylinder Force carburetor throttle plates.

    The Butterflies are to all be Fully Closed at Idle. Once the linkages between are tightened, they will all open the same amount, and there is an Stop to limit their opening. Idle Speed is set simply by adjusting how far the Timing is retarded Just out of Curiosity.... What Service Manual are you...
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