Search results

  1. B

    MR outdrive - no reverse after changing lower shift cable

    Replaced lower shift cable. Now can’t get into reverse. Any ideas of what to look for? I dread having to pull the drive again.
  2. B

    Mercruiser 140, MR outdrive - unidentified fastener

    I pulled the outdrive to replace bellows and this nut fell out. Any ideas what it is and where it goes?
  3. B

    1984 MCM 140 - one or two piece rear main seal?

    I have an oil leak from the rear main seal. Can anyone confirm whether I have a one or two piece seal? S/N 6853440
  4. B

    Fuel pressure loss on Mercruiser 140

    Mid-1980’s Mercruiser 140. Been having fuel starvation issues. Installed fuel pressure gauge to help diagnose. Have sufficient fuel pressure when first starting, but then it drops to zero after running a while. I’ve replaced the line from the pump to the tank and from what I can see the inside...
  5. B

    Mercruiser 140 - low fuel pressure when hot?

    1984 Mercruiser 140. Problems starting when engine is hot. Recently replaced cylinder head with complete tune up. Fuel system is in good shape. Replaced most everything. I installed a fuel pressure gauge. On start up, it runs 4-6 psi. All good. As the engine warms up, pressure star gas to fall...
  6. B

    Engine or outdrive serial number to select correct water pump kit

    I’m sure to be ridiculed for this question, but when selecting an outdrive water pump kit, do I use the engine serial number or the outdrive serial number. This is for a 1984 Mercruiser 140 with the MR drive unit.
  7. B

    3.0 cylinder heads interchangeable?

    Anyone know if cylinder heads for a MCM 140/3.0 with casting numbers 2777770 and 2778954 are interchangeable?
  8. B

    Catastrophic failure? Mercruiser 140

    1984 mercruiser 140. Last year the exhaust shutter failed and the engine overheated. Replaced the broken exhaust shutter and the impeller and it’s housing. Boat started fine on the muffs. Went to the lake today and it ran fine for a half hour then slowly lost power and died. Was running a little...
  9. B

    Mercruiser 140 MR outdrive whine

    Just replaced raw water pump lower and upper housing and impeller. Making a steady whining noise. Have done this job on this boat a half dozen times without an issue. Everything went back together smoothly. Should I worry too much about it?
  10. B

    Fuel pump failure?

    Mercruiser 140, Alpha MR, serial #6853440. Fuel pump is three years old. Gave no warning signs and just quit working. Is that normal? Any recommendations other than replacing with stock? Electric?
  11. B

    Shift interupt switch?? - Mercruiser 140

    1984 Mercruiser 140, serial no. 6873947, Alpha MR I think the shift interrupt switch may be failing and cause an interruption in ignition when the boat warms up. Is there a good way to test the switch? The boat runs well on the water for about an hour an then develops a miss that I cannot for...
  12. B

    Ignition coil overheating - Mercruiser 140

    1984 Mercruiser 140, Alpha MR drive, serial no. 6853440 - I have been chasing an electrical problem for about a year now and am at my wits end. It is not a fuel problem. Symptoms are as follows: Boat starts and runs great for 30-45 minutes, then develops a miss. Miss can be made worse by...
  13. B

    Mercruiser 140 ignition coil voltage

    What should the voltage be when taken on both sides of the coil? I have read until I am blue in the face, including the sticky, and I am still confused. Admittedly, I get my cookies from the low shelf on this stuff. I get readings of 10.5 on the + side and 6.5 on the - side.
  14. B

    MCM 140, Alpha MR, 1984 - unable to locate source of misfire

    Very frustrating. After about an hour of running great, boat develops a misfire, made worse by turning on any electrical source (e.g. blower) and especially by activating trim. I have examined and cleaned wiring including cannon plug and related connections. The miss goes away momentarily but...
  15. B

    Mercruiser 140, Alpha MR - can't locate electrical miss

    I'm at my wit's end. Boat runs great for about an hour, then develops a slight electrical miss which turns into a major misfire causing the engine to shut down. Will re-fire and idle fine but will not accelerate. After another half hour or so, it will begin running normally. I am confident it is...
  16. B

    Mercruiser 140 - how to separate the exhaust elbow assembly from exhaust manifold???

    I am trying to remove the exhaust elbow assembly from the exhaust manifold from a 1984 Mercruiser 140 to be able to more easily remove the exhaust manifold to replace the head gasket, and because it leaks. It seems to be almost welded in place. I have removed the 4 nuts securing it to the...
  17. B

    Mercruiser 140 - new carb - why won't it hold an idle???

    Replaced Mercarb 2bbl on Mercruiser 140. Replaced with Rochester. Starts with electric choke it with very high idle. When choke is off, it will not hold an idle. Have tinkered with idle mix screws to no avail. No apparent vacuum leak. Any ideas?
  18. B

    Burned points

    1984 mercruiser 140 alpha mr. Why did my points burn up. Less than a year old. Very little use. Set gap, dwell and timing within spec when installed. Now have occasional rough running and points are almost completely gone. Any thoughts?
  19. B

    Loss of power/surging at WOT

    1984 Regal Medallion, Mercruiser 140, Alpha M/R, 2bbl Mercarb. The following fuel system parts have been replaced or rebuilt: fuel tank filler hose; fuel tank vent tube; fuel tank pickup cleaned; anti-siphon valve replaced; fuel line from tank to fuel pump replaced; fuel pump and internal...
  20. B

    Merc 3.0 Alpha - What is under front motor mount?

    But more importantly, why did it cave in and can it be fixed? Boat is a 1984 Regal Medallion. Have worked all summer long on it. Runs great! Took it to the lake today. Enjoying the fruits of my labor. Then wham!!! Whatever holds the front motor mounts in place seemingly collapses. Can it be...
Top