Results 1 to 6 of 6

Thread: 3.0l merc

  1. #1
    Worked on one today at work and for some reason was intriqued by it. what kinda performance stuff can you do to this motor and how fast are they? are they good engines?

  2. #2
    I can't get real technical on this topic, but it seems to me that if the 3.0L motors were all that spectacular in the performance arena, then the 2.5L would have been extinct by now. On the other hand, the 300X is based off of the 3.0L block, so who knows.
    I don't think they have the reving capabilities of the 2.5L.

  3. #3
    3.0l's are limited to 6700rpm. More cubes = more torque for bigger single applications. Power? Pro Max 300 made 300hp, 300x makes 315 rated at the prop shaft.
    Upgrades - the usual suspects, port timing, exhaust chest, reeds, etc. 350hp shouldn't be a problem. Still limited to 6700rpm though.
    The 2.5's are for lighter boats or work better with brothers on heavy boats. Higher RPM capability (2.5/260 will go 7750 with stock box), drag motors go >10k.

  4. #4
    sam pioske
    Hey STV guy!! You have answers, How about my lake trip yesterday? My 3.0, 225, 1996, EFI started up as usual - people got in, Engine died first time ever! Restarted died, if it runs at all-its only at idle, give it gas it dies NOW! Yes it has fuel and oil in the res.! Any thoughts would be appriciated. TX Sam

  5. #5
    First thing I would check is fuel pressure. Make sure it doesn't drop when you hit the throttle.

  6. #6
    sam pioske
    Thanks Kieth was thinking fuel! Monday will start on that, reading the book sounds like checking the mech. than high pressure test point valve?? thanks Sam

Similar Threads

  1. Fuel Consumption: Merc 469HO vs. Merc 525
    By Magic34 in forum Sandbar
    Replies: 38
    Last Post: 10-22-2007, 02:48 PM
  2. Merc 502 help
    By Powerquestboy in forum Sandbar
    Replies: 5
    Last Post: 03-27-2007, 10:17 AM
  3. 2.5 merc
    By badluck in forum Outboards
    Replies: 5
    Last Post: 11-16-2006, 05:34 PM
  4. Merc best 2,5's
    By ToffenG in forum Outboards
    Replies: 18
    Last Post: 05-14-2004, 05:19 PM
  5. merc 6.2
    By bordsmnj in forum Out Drive
    Replies: 5
    Last Post: 03-10-2003, 10:12 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts