Page 9 of 11 FirstFirst ... 7891011 LastLast
Results 161 to 180 of 216
  1. Member
    Join Date
    May 2010
    Location
    Prairieville, Louisiana
    Posts
    819
    #161
    "#9 -Get your TPS(throttle position sensor) set richer. Mine is at .102 at idle and .432 at wide open.This keeps the lean sneeze from happening at idle. Not good on reeds and rotating assembly that is pushing the envelope" Excuse my ignorance, but what will doing this mod accomplish on an XB? Thanks.
    Keith Broussard Caney Lake, Louisiana
    2000 TR21 2000 Mercury 250 Pro XB OG980775 14" hydro plate

  2. Member
    Join Date
    Mar 2011
    Location
    Plano, TX
    Posts
    3,072
    #162
    Quote Originally Posted by jrspop View Post
    "#9 -Get your TPS(throttle position sensor) set richer. Mine is at .102 at idle and .432 at wide open.This keeps the lean sneeze from happening at idle. Not good on reeds and rotating assembly that is pushing the envelope" Excuse my ignorance, but what will doing this mod accomplish on an XB? Thanks.
    It isn't a "mod". Just a precaution for the motor pushing the limits. You want plenty of oil supply running WFO. If you have the mods done, listen to Richard! Mine is stock. I run her at .98
    Champion 206
    250XB

  3. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #163
    +1... it does set the fuel curve richer, which is important in cases where any mods have been made that may improve or increase airflow.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  4. Member
    Join Date
    May 2010
    Location
    Prairieville, Louisiana
    Posts
    819
    #164
    Thanks, that's what I was wondering, I did do the cowl mod.
    Keith Broussard Caney Lake, Louisiana
    2000 TR21 2000 Mercury 250 Pro XB OG980775 14" hydro plate

  5. Major Flagelator Gamblinman's Avatar
    Join Date
    Jun 2004
    Location
    Yantis, TX
    Posts
    4,121
    #165
    Even with all the bolt on mods, most 3 liters are pig rich on the top end. Adjusting the TPS to compensate for an idle issue will only make it worse on the top end. I run factory setting and my piston tops are still wet on the top end. I run Simon modified ECUs, 300 heads, fiber reeds, cowl mod. Motor is a 2000 model. Still on stock rings and pistons..never been inside other than changing reeds and heads.

    Gman
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."

  6. Member
    Join Date
    Oct 2018
    Location
    Italia
    Posts
    4
    #166
    Hello how to modification the divider 4 butterflies ... I read that you modification the divider between 1.2 3.4 5.6 cylinders

  7. Major Flagelator Gamblinman's Avatar
    Join Date
    Jun 2004
    Location
    Yantis, TX
    Posts
    4,121
    #167
    Quote Originally Posted by Devidmovistar View Post
    Hello how to modification the divider 4 butterflies ... I read that you modification the divider between 1.2 3.4 5.6 cylinders
    Not worth the time and investment. The loss in low end torque will kill any dividends for such mods. Get the injectors out of the airflow.
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."

  8. Member
    Join Date
    Oct 2018
    Location
    Italia
    Posts
    4
    #168
    250 efi vs 300 promax
    hi Guys I wanted to compare 2 engines ... I have a 250 efi mercury with control units by simon light flywheel, group 4 butterflies, change heads 130.3 psi, modified exhaust ... what differences to 300 promax ...? are fast equal?

  9. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #169
    Essentially equal, until you said something about modified exhaust. Almost always kills the low end torque with little or no gain at top end.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  10. Member
    Join Date
    Oct 2018
    Location
    Italia
    Posts
    4
    #170
    modified discharge ... I forgot to write. then it is not convenient to sell my 250 to change with 300 promax? the blocks are the same?

  11. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #171
    Given what you have done to yours already, I would be very surprised if the 300 perfomed as well as what you already have.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  12. Member
    Join Date
    Oct 2018
    Location
    Italia
    Posts
    4
    #172
    I understand ... comparing the 2 mechanical engine part blocks, are there any typical differences in the exhaust windows in the cylinder block?

  13. Mercury 3L/4 Stroke/Verado Moderator EuropeanAM's Avatar
    Join Date
    Apr 2008
    Location
    Greenville, SC (US)
    Posts
    94,941
    #173
    There were a couple versions of both blocks- with different sleeves. Sleeves were different, though the differences were quite subtle. See specifications for each engine, or google "Advanced Sleeve" and lookup the sleeve particulars in their catalog for a more detailed set of specs.


    Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
    Still consider myself a "Marine Apprentice" after 47 years (learn something new every day).
    Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor

  14. Member
    Join Date
    Jun 2015
    Location
    Prosperity, SC Lake Murray
    Posts
    123
    #174
    MER# SER OTO19231... Motor runs real strong with stock 225 ecu's, cowl mod, Boysen Duel stage reed, adapter plate has been drilled to 3/8 turning 5900 with 26 Tempest..Decided to play a little now I went backwards..I had Jay Smith cut me some stock o-ring heads to 63cc heads...I also had Simon flash 2 ecu boxes to 300 ING. /250XB Fuel. Had the TPS SET per spec with the correct plugs gaped to .35....Running 93 Octane gas.... Motor seems to pull about the same with hole shot up to about 5,000.....Then it seems like it is surging and falling on its face....So with that being said I let out of the gas back to about 4500 rpms seems to be fine again... I give it all the gas and it only goes up to 5500 rpms. Then i feel it surging so I let out the gas again. Last thing I want to do it hurt the motor....To me it seems it is getting the gas but the spark is not there. I'm concerned something did not work correctly on the reflash on the ING box, Reason I say this when I loaded the boat I did a load test on motor...As I gave it more and more gas it sounded like it was loading up and was wanting to shut down as it was starting to surge again....About to put my old stock boxes back on tomorrow .... Any Thoughts??
    Darrell Shull
    Prosperity, SC
    2021 Charger 210 Elite , 2023 Mercury V8 250 Pro XS

  15. Member
    Join Date
    Jul 2004
    Location
    Penn PA
    Posts
    15,104
    #175
    Yep, put the stock boxes back on and see if the motor gains RPM's @ WOT...….



  16. Major Flagelator Gamblinman's Avatar
    Join Date
    Jun 2004
    Location
    Yantis, TX
    Posts
    4,121
    #176
    I had the same issue trying to find 2 boxes that would work together.

    For whatever reason, some boxes just don't work together. I can't explain it, and neither can Eric Simon. I tried lots of boxes before I finally found 2 that will work. I have 2 boxes reworked by Eric that won't work together. Same thing as you...runs like a raped ape till it hits 5000 rpms and it hits a wall. I can tell you when you do find boxes that work together, its like a night and day difference in how the motor performs.
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."

  17. Member
    Join Date
    Jun 2015
    Location
    Prosperity, SC Lake Murray
    Posts
    123
    #177
    Man I'm ready for that...I hope Eric will work with me
    Darrell Shull
    Prosperity, SC
    2021 Charger 210 Elite , 2023 Mercury V8 250 Pro XS

  18. Member
    Join Date
    Jun 2015
    Location
    Prosperity, SC Lake Murray
    Posts
    123
    #178
    I changed out the ING ECU first and installed my stock 225 EFI ING ECU....Pretty much did the same thing ran up to 5200 and started falling on it face..brought it back to dock and installed my stock 225 EFI FUEL ECU. Ran all the way up to 5900 rpms and felt a little stronger with the 300 PM heads. Really wish those other boxes I got back from Eric Simon would light it up....I will have to give Eric a call and see what is going on.Glad nothing is going on with the motor
    Darrell Shull
    Prosperity, SC
    2021 Charger 210 Elite , 2023 Mercury V8 250 Pro XS

  19. Member
    Join Date
    Jul 2004
    Location
    Penn PA
    Posts
    15,104
    #179
    I figured it was the boxes......At least you know now what part isn't working.



  20. Major Flagelator Gamblinman's Avatar
    Join Date
    Jun 2004
    Location
    Yantis, TX
    Posts
    4,121
    #180
    Its like the iridium plug debacle. Some folks have all kinds of electrical trouble running them in their 225EFI's. Mine runs like a champ with them. The last set made 5 years and was still running strong when I put a new set in. I pulled them once or twice a year and looked at the color and checked the gap. I put Champions in it and in six months, they're shot. black, and all kinds of deposits on the insulators. Starts stumbling out of the hole and poor idle quality.

    I hope you can get this figured out. Actually, there are quite a few that have had this same issue when switching boxes. I've never seen or heard of an exact cure. They either give up, or like me, finally find 2 boxes that run together. Help is getting harder and harder to find being the twin box motors are all 17 years or older.
    "Better to remain silent and be thought a fool than to speak out and remove all doubt."

Page 9 of 11 FirstFirst ... 7891011 LastLast

Similar Threads

  1. Mods for an XB what and whom????
    By bullet714 in forum Bullet Boats
    Replies: 2
    Last Post: 02-21-2014, 12:09 AM
  2. 175 EFI Mods
    By Royjulius in forum Mercury - 2.0/ 2.4/ 2.5 Liter High Performance
    Replies: 3
    Last Post: 07-26-2011, 10:14 AM
  3. What if any mods can be done........
    By Pro-Hunt in forum Mercury - 3 Liter & 3 Liter High Performance
    Replies: 2
    Last Post: 07-04-2011, 07:18 AM
  4. 250 SHO mods
    By gutterman1157 in forum Yamaha Motors - High Performance
    Replies: 4
    Last Post: 03-31-2011, 12:33 PM
  5. Tech Talk---Bass Boat Mods
    By Big Johnson in forum Virginia Fishing
    Replies: 25
    Last Post: 09-26-2007, 03:50 AM

Tags for this Thread