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  1. Brentathon

    Alpha One Stalls in Reverse only when giving gas

    I have an 5.7 Alpha One ("Gen 1"); and it shifts fine in forward and into reverse. But if/when I go to give it throttle in Reverse, it stalls. I can see the Lever Assy (13051A4) actuate the cut-out switch on the shift bracket. Would that be a sign of the lower shift cable being bad?.... even...
  2. Brentathon

    5.7L Vortec vs Pre-Vortec Height Dimension?

    Yes.... that’s exactly what I’m looking for.... the difference going from my Rochester Quadrajet 4-barrel to the Vortec (higher intake manifold?) and I believe they use a 2-barrel..?
  3. Brentathon

    Exhaust Bellows

    It’s louder.... I hated it... it was worth the extra effort for me, to install the bellows.
  4. Brentathon

    5.7L Vortec vs Pre-Vortec Height Dimension?

    Does anyone know how much higher the Vortec 5.7L is versus the pre-vortec GM 5.7 1988-1995 (s/n 0F_____ thru 0F_____)? I’m looking to replace my pre-Vortec, and would consider a Vortec if it would fit (under the deck engine cover).
  5. Brentathon

    Alpha 'Gen I' Trim Cylinder Continuity

    Every year, I always check continuity with ALL sections of my sterndrive. This year, I've noticed that one of my cylinders does not have continuity with the rest of the drive (I usually touch the probe on an exposed surface of the rod). Are the cylinders only connected (electrically) to the...
  6. Brentathon

    Impressed by Sierra warranty

    Sent back a defective impeller for my Alpha One (rubber loosened around brass hub), and they reimbursed me for parts, haul-out, and mechanic fees. Nice to finally "catch a break" in this industry.
  7. Brentathon

    5.7 Thunderbolt IV Timing

    I want to check timing. Was there a revision to the timing advance curve in the Service Manual #15? That curve shows the advance starting as slow as the 400-600 rpm range (see attached)....:confused: If the "base timing" is 8 deg BTDC, the curve shows I should add 5 degrees to that (i.e. 13...
  8. Brentathon

    5.7 Alpha High-RPM Overheat - Can't Solve

    I think this high-rpm overheating has been plaguing me for seasons, now. I believe I’m getting just barely enough water in from the drive, to not overheat up to my normal cruising rpm’s (3600rpm). While trying out a new prop (WOT runs), I now confirmed I overheat. Plus, bay water is now in...
  9. Brentathon

    Max Prop Diameter for Alpha One

    What's the maximum prop diameter that you can run on an Alpha One? I was thinking of buying a 16"D x 16"P prop. I expect I'll have to use the flat trim tab anode.
  10. Brentathon

    Fogging Engine - Beware

    I was fogging my engine yesterday by spraying the fogging oil into the carburetor while at fast idle. I fogged until the engine stalled (approx 10 sec), and then sprayed some more into the carb so I could crank it over with some additional oil......when.....PUFF!.......the carb puffed-out a...
  11. Brentathon

    Darn Waffle Zinc!

    :mad: Again this season, my waffle zinc (Alpha) must not have had a good electrical bonding, as it didn't corrode much at all. This is quite frustrating. All the other zincs are approx 50% smaller, and my trim tab zinc on the anti-ventilation plate was even missing half way through the season...
  12. Brentathon

    Alpha One Trim Tab Anode

    This is the second or third time I've lost my trim tab anode (the one that bolts onto the anti-ventilation plate). Very annoying....I use a large adjustable wrench on the allen key, and really tighten them, too! And, 2 weeks prior, I checked and it wasn't corroded too much, and still...
  13. Brentathon

    Dashboard Clock

    I was wondering what others have done to add a dashboard clock. I was tired of having LCD clocks get fried by the sun/heat. After a long search, I simply settled on buying a cheap ($8) analog (with hands) Casio watch, removing the band, and sticking it on with double-sided tape. Is there really...
  14. Brentathon

    Water Heater Life

    I have a 6 gal Seaward water heater, that uses either shore power or engine coolant water to heat water. My engine is raw water (saltwater) cooled, and I was wondering how long these types of water heaters last. Has anyone had the heat exchanger (raw water) portion of this type of heater...
  15. Brentathon

    Shaft slipping within Gimbal Bearing

    Can the coupling end of the outdrive's shaft ("yoke assembly") spin/slip within the gimbal bearing? Because I hear a strange sound at high rpm's (+3800), and I noticed that my O/D's shaft was rusty directly aft of both O-rings (right up against the yoke), I'm not sure why. The gimbal bearing...
  16. Brentathon

    Power/RPM Loss Getting on Plane

    '91 Merc 5.7 Alpha w/ 4-barrel Rochester Quadrajet: I had passengers toward the stern (heavily loaded), and was attempting to get up on plane, when after approx 10 or 15 sec of not accelerating (rpm's stuck aro 3100), the rpm's started decreasing. I backed off throttle, and heard some back...
  17. Brentathon

    Alternator application for 5.7 Mercruiser

    I have a 1990 5.7 Alpha, and they seem to call out a 55 amp alternator 817119A4 (Sierra p/n 18-5966). Is there any problem using a 65 Amp alternator (sierra p/n 18-5965) instead? It looks like Sierra also claims their 65 amp replaces the 817119A4, too.
  18. Brentathon

    Example of Crevice Corrosion

    Here's a good example of how stainless steel can corrode (significantly) in an environment where there's a lack of oxygen. This is a screw that was in my transom, for my swim platform supports. This is why I HATE fasteners used below waterline. Note how the head of the screw (which is submerged...
  19. Brentathon

    "Home Made" Temp Alarm

    Not sure if anyone has an issue with the way I did this, but since my 1991 boat didn't come with the Temp & Oil alarm system, I bought the Merc temp switch (p/n 48952), and simply wired-up a 12 Volt source from my ignition switch. I would have to jump the wire to ground to test the alarm, and if...
  20. Brentathon

    Upper Swivel Shaft Seal is FIXED!!!

    (1991 Merc 5.7 Alpha) I launched the boat this past weekend, and was VERY happy not to see a leak from my Upper Swivel Shaft Seal....due to the replacement. I'll try to post some pics of the old parts. The non-stainless steel swivel shaft (a "design flaw" in my opinion) had significant...
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