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  1. Scott06

    75 Holiday Repower

    Sounds like with your comments here and the performance numbers Bobdo shared, your plan of putting the 4.3 in will meet your needs well.
  2. Scott06

    75 Holiday Repower

    I think you will see a noticeable difference in power. Im not sure whatyour expectations are but at 22 ft you could go the next step up to a 5.7 If you really want it to be quick. what year is the 4.3? 96 and later is the votecs and should be good for 220 hp Witha 4 bbl carb
  3. Scott06

    3.0 L mercruiser 4 cylinder assistance

    This link to an industrial version if the 3.0 shows a threaded block plug there as well as the plug on the port side. http://www.allpowerlabs.com/wp-content/uploads/2015/05/GM_PSI-3.0L-Engine-Service-Manual.pdf its on page 31in the parts drawing. i had a 1990 3.0 for many years never noticed a...
  4. Scott06

    Alpha1 Gen2 outdrive ratio question

    I would think if you buy the 1.47 ratio drive and get a prop 2" lower pitch you will have about the same rpm and performance that you do now assuming it is properly pitched and hitting the correct WOT RPM. I repowered a 4.3 V6 boat (21 ft searay bowrider) with a 5.0 carbed engine, kept the...
  5. Scott06

    Prop Suggestions

    I had a simlar size searay 170 with 3.0 and had good luck with 4 blade Michigan Vortex Props (they make both a 3 and 4 blade vortex). I demoed a 16" pitch and 18" ended up buying both used the 18" for general cruising/tubing and 16" for skiing and wakeboarding. Big difference in holeshot, stern...
  6. Scott06

    Bad carb

    Not really. I think the $350 is not for an oem mercarb but an aftermarket bolt in replacement like sierra sells? other option if you want a turn key is to buy one rebuilt https://flyingfishcarburetors.com/Marine-Boat-merCruiser-Rochester-OMC.htm#merc your carb number is listed partway down the...
  7. Scott06

    Merc Alpha4 no longer available. What to replace it with?

    Rev 4 pitch is 21”. the spitfire 23” is right at the rev limiter so i would have been over with a smaller pitch. compared to the sales pitch in the merc literature i gotta say the spitfire wasn't impressive. I have a 1.81 drive as my boat was originally a 4.3 powered boat that i repowered with...
  8. Scott06

    Merc Alpha4 no longer available. What to replace it with?

    21” rev 4. My boat has a steeper drive ratio 1.81 than is typical. Boat originally was a 4.3, previous owner cracked the block, i bought it knowing this. when i repowered i put in a 5.0 but didnt want to regear or swap the drive since it only had 37 hrs on clock... bottom line works perfectly...
  9. Scott06

    Merc Alpha4 no longer available. What to replace it with?

    Pretty sure it is available in inch pitch increments for the alpha drive , assumed you meant hub diameter not prop blade diameter. if you liked the alpha 4 and are ok with aluminum try a michigan vortex 4 blade in the same pitch.i had very good results on my last boat with these. I think they...
  10. Scott06

    Knock sensor for Thunderbolt V

    Is your new engine carburated you mention a newer ecm? Is it fuel injected ? Ive never seen a knock sensor on a carbed V6, and the mercruiser electrical manual (4D) doesn’t show a V6 wiring diagram with a knock sensor. most 5.0 s don't have them either. as AD outlined you could wire it up and...
  11. Scott06

    4.3 Swap, advice needed

    As bondo mentions should swap over. You can keep the truck cam. Change the head gaskets for marine and check the freeze plugs are brass or stainless. Make sure you use the marine alternator starter and distributor.you will need a marine block water circulation pump You will end up with vortec...
  12. Scott06

    New Boat Purchase - Stuck Manifold drain plug

    It may actually be ok. I could never figure this out but i winterized my 1990 3.0 for 20 years. I always took that plug out but never git any water to come out ( no it wasn’t plugged ). didn’t make sense to me but the water must have been siphoning out the block via the hose feeding it. always...
  13. Scott06

    Omc 4.3 carburetor issue/identification

    If you take the numbers off the carb should be stamped into side of bowl. look up Mikes carburetor parts on line. I also agree it is either a mercarb or a rochester which share a common lineage. Either way mikes will set you up with the correct kit.
  14. Scott06

    Mercruiser 6.2L Bravo 3 I/O alignment problems

    Wonder if you may need to center the gimbal bearing again like in this video
  15. Scott06

    RPMs too high?

    Verify your tach is accurate first. Rule of thumb is 1" pitch change (+/-) will increase or decrase rpm by 200 ish if you are staying with the same prop type. Depending on the prop type cupping etc if you change the type of prop like 3 to 4 blade, basic aluminum to SS with a lot of cup as well...
  16. Scott06

    No Start, but should

    Have you looked at the spark with a spark gap tester? You may have a spark but is it strong enough to light the fuel. spray a touch of starting fluid down the carb -if that doesnt light off you are loosing spark strength somehwere. If it does light off and run till the starting fluid is gone...
  17. Scott06

    Mercruiser 350 mag MIE ECM

    Take the coil wire off the ditributor gorund it and crank it over to see if you have spark to the cap. If you do you know its cap rotor or some how getting grounded inside the ditrbutor.
  18. Scott06

    Exhaust Bellows

    yes only slightly louder on plane, It would probably be the same volume as now with one end off the bellows...
  19. Scott06

    Best prop fuel economy

    If your tach is accurate I would think a 19" would bring you down to 4900 or so, but defintiely verify the tach before investing in props.... 17" is typically used as a pwoer prop for skiing or watersports, so 19 should be a good blend of holeshot and lower cruising rpm
  20. Scott06

    Ground Wire on EzLoader Trailer--Mystery

    White is the ground, blue is generally the reverse lock out , maybe one of the brown is it? here is a generic diagram https://www.northtexastrailers.com/check-over-trailers-dealership--trailer-wiring-diagrams
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