40 hp johnson rpm's

Discussion in 'Bubba's Outboards' started by shuorc, Oct 14, 2007.

  1. shuorc

    shuorc New Member

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    fl
    After getting my tach fixed using the wiring color code at top of forum(thanks) my '92 tracker at WOT is 3500 rpm at 25 mph, does this sound right?--shu
     
  2. Bubbakat

    Bubbakat New Member

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    4,532
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    McMinnvill
    Not enough r,s for that motor should be more like 48 to 55 hundred.

    Need a model number to find out what range it should be working in but at 35 she is laboring hard.
     

  3. shuorc

    shuorc New Member

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    not sure the tach is working right after market ignition by CDI. Motor Model is tj40elenm. Thanks for the response--shu
     
  4. Bubbakat

    Bubbakat New Member

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    4,532
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    McMinnvill
    Is this a new tach or is it an old one and does it have the pole setting on the back of the tach.
     
  5. dougc

    dougc Active Member

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    1,709
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    Independen
    What boat and prop are you running? I've got a '93 Evinrude 40 on a 16' Tracker v-hull running 32 mph with 2 guys and a full load. Runs 5100 rpm with a 12.25x15 prop.
     
  6. shuorc

    shuorc New Member

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    fl
    old tach and has a setting on the back, wasn't working because of a broken grey wire in harness as it enters engine, hasn't worked in a long time. 2 years ago had a fit with ignition and a local mechanic replaced coil with a CDI 113-4767. Motor seems to run as well as ever but the tach reading seemed low to me.--shu
     
  7. Bubbakat

    Bubbakat New Member

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    4,532
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    McMinnvill
    That engine should work between 4500 and 5500 the 55 is top end. Any where around 5000 and up to 5500 will do great.
    It should be a 12 pole so it should set the tach at 6p on the setting. I have seen some of the foreign jobs set at 5p but 5that is abnormnal.

    I have a test some where in my files that will telol you if the tach is good or not but it could be giving you a false reading. If you have a gps then test your speed and that will get close to the range but won't take the place of a tach.

    You might try putting a 2000 ohm resistor between the signal wire (gray) and the ground and see if that will help.
     
  8. shuorc

    shuorc New Member

    Messages:
    116
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    fl
    Would appreciate the info on how to test the tach and do have a gps available to test the speed, will do that tomorrow afternoon when i take grandson fishing. Boat is a '92 tracker pro-17, can't see any info on prop, not much of a load. Thanks for the responses--shu
     
  9. shuorc

    shuorc New Member

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    fl
    tach has to be wrong, lake was rough so couldn't get in the main lake but when tach showed 3000 gps showed 28.1 mph(short run) speed was increasing but tach indication was not. haven't got to look at the setting yet.
     
  10. tofish

    tofish New Member

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    3,923
    State:
    arizona
    Shuorc, i have the same boat and motor you do. same yr also. added another console and walk through windshield to it. when by myself, i've gotten it up to 32mph at 5200 rpm. this weekend, with another guy, loaded with enough gear and bait to spend two days on river, at 4200 rpm, ran about 23mph. i was going slower, so started calling around. changed props to a 17 pitch and found it was perfect for boat. my want to think of prop pitch. the johnson dealer said the motor should max out rpms between 5000-5500 maximum. sounds like maybe (IMO) a possible pitch problem like i had. tracker sent boat with wrong prop on it.
    gary
     
  11. shuorc

    shuorc New Member

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    fl
    Got another problem now the tilt assist cylinder froze up(recently replaced -used) so will have to deal with that. I believe my speed is ok just the tach reading is incorrect, love the boat but sure have had a fit with engine. Thanks for the info--shu
     
  12. shuorc

    shuorc New Member

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    116
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    fl
    Got tilt assist working again----back to tach, settings on back read 4, unknown, 10, 12 with notch either on 4 or 10 is the unknown(label has been wet) position 6?? Haven't found a 2000 ohm resistor but somewhere in my pile of electronics goodies one has been waiting for years.---shu
     
  13. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    That unknown should be your 6p setting.
     
  14. shuorc

    shuorc New Member

    Messages:
    116
    State:
    fl
    Lake was nice this morning ran wide open only got 28.4 mph with tach on 6 showed 2800 rpm, changed back to 4 showed 3000 rpm at same speed. will go thru linkage setup.--shu
     
  15. shuorc

    shuorc New Member

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    116
    State:
    fl
    Went to the library and got shop manual, went thru linkage setup(only minor changes needed) may need to redo idle. Think i'll cut the grey wire that started this and go fishing.--shu