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  1. S

    Totally baffling !!! Impeller replaced !! And not pumping

    Make sure the tube going from lower to upper is clocked correctly. It’s in the service manual
  2. S

    5.7 Vortec Runs Great On Land but Bogs Under Load in Water

    The reason I suggested the engine builders Holley video is to UNDERSTAND how a carburetor functions. How the power valve interacts with other components, how jet sizes are determined. Once you understand how or the physics troubleshooting becomes efficient vs monkey see monkey try.
  3. S

    Minimum transom thickness tolerance of alpha mercruiser sterndrive?

    Sterndrive no issue. If you had outboard hanging off you be close. Your have no worries.
  4. S

    Flushing Muffs

    Dont do what my dumb ass did. I thought I would rotate the rectangular muffs 90 degrees to fit the vertical water intake grates better, boat temp skyrocketed when flushing so I shut it off. Thought wow I lucky got water pump just in time, changed it. It was perfect. When I rotated the muffs...
  5. S

    when do you know your flappers need to be replaced

    only reason I would replace flappers is if they rattle, rubbing coating wears off and they tap on the exhaust "pipe" at idle. Sounds like a can of marbles.
  6. S

    Mercruiser 5.0 MPI #3 cylinder ignition miss

    The AC 41-993 are Iridium not Platinum. Box indicated, AC deIco website indicated, rebate validated. I am 99% sure they are genuine since the amazon store was AC Delco. I checked gap very carefully and all had the little pad of alloy on the ground strap. The ngk IX did not have the alloy...
  7. S

    2002 Mercruiser 350 Mag MPI showing high temp and engaging guardian system

    What kind of outdrive or is it inboard. Don't forget to look at what could be blocking or impeding flow TOO the pump on the suction side. Kinked hose, air leak, etc.
  8. S

    5.7 Vortec Runs Great On Land but Bogs Under Load in Water

    Air mixture isn't set with timing light, it set with a vacuum gauge. Google or search engine masters, its a tv show. About a month ago they explained how a Holley Carburator worked, the theory and how to adjust. You set fuel mixture to highest rpm then readjust idle. What is your full...
  9. S

    Mercruiser 5.0 MPI #3 cylinder ignition miss

    Solved, My AC deco 41-993 spark plugs eliminated the #3 miss and eliminated the heavy gas smell in exhaust (I liked as it was bad for the environment) and it completely eliminated the flat spot at max load in the 3-4Krpm range. Again I purchased 8 off Amazon for $25 (now $30) and got a $24...
  10. S

    1978 5.7l pre-alpha with alpha gen 1 drive over heating

    I love the empty miller lite can in the bilge. At lease somebody had a good time.
  11. S

    2014 MPI fault codes 321 & 322

    I was thinking the same as nola mike. its failing both ways, lean and rich, common denominator is o2 sensor. O2 sensors cheap, either swap sides or buy a new one. Did someone flush the engine or throttle body and contaminate the sensor?
  12. S

    Engine to Outdrive Alignment Tool

    No, tolerance isn't "tight enough". In other words your driveshaft will slide in where the alignment tool won't.
  13. S

    2014 MPI fault codes 321 & 322

    Sorry manual all but useless. My suggestion buy PCM 555 and associated wiring harness. If an O2 sensor is weak or bad it will cause the codes to throw.
  14. S

    2014 MPI fault codes 321 & 322

    I had 321 after the boat sat all winter. Never came back. Make sure you clear the trouble codes and history or the codes will come back. So go into history and it will tell you exactly when the alarm hit and what all the parameters were, you need to clear that also. To rich sounds like...
  15. S

    Ever see a twisted drive shaft?

    Incredible. On my old boat I would hit crap and engine would stall multiple times. Splines always looked perfect
  16. S

    Mercruiser 260 weird misfire

    Gas tank vent, fuel hose delaminating inside and pinching off flow. I pretty sure you have coast guard approved fuel lines so they should be good but might want to check.
  17. S

    Engine Bogging Down When Cold

    when it bogs is it a "flat spot" or does it sputter
  18. S

    Mercruiser 5.0 MPI #3 cylinder ignition miss

    Just a quick update/confirm/*****. As I always knew certified mechanics/techs are idiots. In my 56 years of living I have only hired one contractor in my life to replace my roof. My boats, atv's, wave runners, cars, pluming, electrical I do myself, never a hostage to their schedules. Well I...
  19. S

    Light u-joint noise hard turn starboard

    You already wasted more time then it would have taken to pull the outdrive and replace the u-joint. On all my boats, friends boats over 30 years never had a bad u-joint, I suspect you found a symptom and the problem is a water leak contaminating you u-joint grease
  20. S

    Preferred method to fog a Cat equipped engine?

    DO NOTHING BUT STABILIZER IN GAS IF YOU WANT. Last you thing you want is fouled spark plugs, fouled 4 oxygen sensors, fouled catalyst. boat will rot out before you ever wear it out.
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