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  1. Brentathon

    Anode Continuity - a must do

    Always check continuity with a multimeter, especially when first installing. You’d be surprised how often you WON’T have a good electrical bond, without cleaning, buffing, scraping the contact surfaces. I also use a dremel and wire wheel in bolt threads. The white zinc oxide that often remains...
  2. Brentathon

    BEWARE of Faulty 87290A4 Thermostat Housing sold on Amazon!

    I recently purchased a supposed GLM 13230 (Mecruiser # 87290A4) on Amazon, and it's missing the hidden internal hole, and caused my 5.7 to overheat! Ughhh!!!! This part also doesn't have the "GLM" letters cast into the housing, like the one I'm replacing, so it's suspect whether it's truly a...
  3. Brentathon

    5.7 Cast Iron Intake Manifold - Salt (‘raw’) Water Cooled

    How long do these cast iron manifolds last?…. Geez. 😬 This is saltwater cooled since 1991. I guess ya just run them until they fail….?
  4. Brentathon

    Thread repair on Bell Housing

    Ughh… I cross-threaded the brass shift cable housing part into my bell housing (Alpha One - “gen I”). I believe it’s a straight pipe thread; 1/4-18 NPS, while the shift cable housing has a tapered pipe fitting. I plan to use a NPS tap to clean up threads, and see how damaged they are. Has...
  5. Brentathon

    Shift Cable Replacement

    On an Alpha One (1st gen)… Can I replace the lower shift cable WITHOUT removing the Bell Housing? I really don’t feel like messing with or replacing the U-joint and Exhaust bellows….just yet. I just want to just replace the shift cable. Has anyone done this with Bell Housing not removed? Thanks!
  6. Brentathon

    I Lost Reverse

    1990 5.7 Alpha One (Gen I). Was stalling when first launched the boat in spring; I adjusted the 6” shift cable dimension with the brass barrel nut (didn’t have to adjust it much); then it shifted fine up until last time I used it. Wouldn’t go into reverse (gears chattered), or would stall. So...
  7. 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...
  8. 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).
  9. 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...
  10. 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.
  11. 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...
  12. 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...
  13. 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.
  14. 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...
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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...
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