Engine Upgrade

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by Amberjack_Jae, Apr 15, 2019.

  1. Amberjack_Jae

    Amberjack_Jae New Member

    11
    Jan 27, 2017
    Florida Gulf Coast
    2000 Sea Ray 290 Amberjack
    "Paper Trail"
    5.0 Mercruiser w/Bravo III
    Good Afternoon all,
    This is a question for all the marine engine machanics out there. I have a 2000 Searay 290 Amberjack with twin 5.0 (305) engines, making 260 hp according to the manuals. The boat also has Bravo 3 outdrives. Right now, one engine has seized and is in need of rebuild/replace. I would like to do the same work on both now if possible. The several shops I have talked to, say they have a hard time finding the 5.0 (305) block as it is no longer produced, and I should look to upgrading to 350's. SO I have looked online and found several 5.7 engine long blocks for pretty reasonable prices, ($2200 - $3800). Now I have several questions, will the outdrives handle the extra horsepower, and what would be their limit? Would the outdrives need to be modified in anyway. Is a long block the way to go, as opposed to buying a built engine which I have found anywhere from $8500-$14000, way out of my budget. I have rebuilt auto engines in the past.. so I do have a working knowledge, but never a marine engine. The prices I am being quoted are about $11000 and engine. I dont think the boat is worth that anymore.. LOL..SO.. good Idea to attempt myself? or should I keep lookng for a marine machanic. Sorry if this is long winded.. I am thinking as I go. Any help from anyone would be greatly appreciated. Also I am on the gulf coast of florida, (Ruskin) if anyone knows of a good mechanic down this way, please chime in.
    Thank you all for your time and wisdom

    Will
     
  2. JimG

    JimG Well-Known Member SILVER Sponsor

    Nov 4, 2008
    Southern WV
    2007 310 DA
    Kohler 5ECD
    Twin 350 Mags
    Raw Water Cooled
    V-Drives
    The B3's will do fine with the 350's... very common combination.

    I'm not sure about the drive match up from 305's to 350's, I would think there would be no difference... someone here should be able to confirm.

    If you have rebuilt engines before, I would not hesitate to take this on yourself if you have the place to work and some sort of lift to get them out and in.
     
  3. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    No problem with a Bravo 3 and a 350.. They use B3's on the 496 motors.

    A long block is a good replacement, but you should consider replacing any piece that's been exposed to salt water. ie heads, intake, exhaust, as well as the starter, oil pan, etc.
     
  4. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    Be sure to check the outdrive gear ratios going from a 5.0 to a 5.7. I know they are the same on an Alpha drive but you should find out now.

    I think that would be a great upgrade.
     
  5. Amberjack_Jae

    Amberjack_Jae New Member

    11
    Jan 27, 2017
    Florida Gulf Coast
    2000 Sea Ray 290 Amberjack
    "Paper Trail"
    5.0 Mercruiser w/Bravo III
    Thank you all for such fast responses...I will look into ordering the long blocks..
     
  6. Ididntdoit

    Ididntdoit Well-Known Member GOLD Sponsor

    Dec 5, 2007
    Newport, RI
    300 Sundancer
    5.0MPI Bravo III
    You can still get 305s........right from GM or any rebuilder like Michigan Motors......Just replace the 1 motor with what was in there and move on if the compression/leakdown look good on the other one
     
    Rusted Nut likes this.
  7. dtfeld

    dtfeld Water Contrails

    Jun 5, 2016
    Milton, GA
    410 Sundancer
    2001
    Axiom 12 MFD
    Cat 3126 V-Drives
    Looks like a marinized 305 on eBay is 1250-1700.

    The one thing you’ll need to nail down is if the 350 needs a different gear ratio B3. It may be possible that the current gear ratio works, but you might need new prop sets. Just things to think about if going to a different engine.

    Getting a 305 would be much more strait forward.
     
  8. WV 320 Dancer

    WV 320 Dancer Active Member SILVER Sponsor

    694
    Oct 28, 2018
    2003 Sea Ray Sundancer 320
    Twin 350 MAG - V Drive
    I would strongly recommend that you look at Jasper rebuilt marine long blocks. I have seen many boats on our river use these with excellent results. They have 305’s all day every day. Or, if it were me yes I would step up to 350’s from Jasper as well.
     
    Chris-380 likes this.
  9. sbw1

    sbw1 Well-Known Member

    Oct 10, 2006
    West Michigan
    This is listed in my signature
    This is listed in my signature
    2808670-R1-015-6.jpg Just a comment on the "extra HP" of the 350 CID engine. My first Sea Ray had a 350 Merc I/O for power. That was a sweet engine that ran for thousands of hours. It made 260 HP. Run a 350 at 3000 RPMs and it will last a long time.
     
  10. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    You make no mention of carbed or efi. EFI upgrade from 5 to 5.7 will require ECM reflash. Carb version will need rejetting at a minimum.
     
  11. dan313

    dan313 Member

    159
    Sep 27, 2009
    Long Island
    2005 270 Amberjack
    350 Mag Bravo3
    I re-powered 4 years ago with a 350 Jasper block. No Issues to date and saved a bunch of money.
     
    Chris-380 and WV 320 Dancer like this.
  12. Amberjack_Jae

    Amberjack_Jae New Member

    11
    Jan 27, 2017
    Florida Gulf Coast
    2000 Sea Ray 290 Amberjack
    "Paper Trail"
    5.0 Mercruiser w/Bravo III
    Thank you all for your quick responses. I have heard about the Jasper engines and I am going to look at them. Also the engines are EFI not carbed. Hope to get things done soon as I am missing the water something crazy.
    Thanks again all.
     
  13. Brite Idea

    Brite Idea Member

    151
    Nov 5, 2011
    Long Island, New York
    270 Sundancer 2000
    twin 4.3 TBI Merecrusier Alpha Gen II counter rotating drives
    i strongly recommend the 5.7 over the 5.0 you will not be disappointed.
     
  14. boatrboy

    boatrboy Active Member

    Oct 3, 2006
    Orange, CT
    1999 270 Da
    7.4 MPI w/B3
    I agree.
    I never heard anyone say "I wish I had less horsepower"
     
  15. Jimmy Buoy

    Jimmy Buoy Well-Known Member

    Dec 3, 2008
    Sarnia, Ontario, Canada
    340 Amberjack
    twin 8.1S 370 Hp + 4.5 Westerbeke Genset
    Both 5.0 and 5.7 engines probably have similar WOT specs which means that your props will be spinning at the same RPM's with either engines at the max WOT spec. That being said, the additional power from the 5.7's might allow the engines to spin those props faster than WOT specs which will mean you either have to change the drive ratios or go with more aggressive props or over-rev the engines (not good) - both of which are rather expensive propositions...
     
  16. SCORPIO

    SCORPIO Well-Known Member SILVER Sponsor

    Apr 7, 2008
    Delaware
    1989 300 DA
    Twin 5.7 Merc Alpha I
    I'd go to 350s as price will be about the same. Have you ever heard a boater say "my boat has too much power"? The hull will like the extra horses. I got complete, new engines from Michiganmotorz in 2016 that have been great. Best pricing on complete engines I could find. The 350 should be a direct bolt in swap for your 305s.
     
  17. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    The fly in the ointment will be, he will; need different injectors and a diff. ECM to power them. Neither of those are cheap.
     
    techmitch likes this.
  18. SCORPIO

    SCORPIO Well-Known Member SILVER Sponsor

    Apr 7, 2008
    Delaware
    1989 300 DA
    Twin 5.7 Merc Alpha I
    He didn't mention if the boat is FI or carbs. I'm not familiar with that uears equipment so maybe it is FI. If so, then staying with the 305s would be the more cost effective route.
     
  19. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx
    502 mpi Bravo 1
    Post 12
     

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