My Johnson ain't what it used to be. . .

Discussion in 'Outboard Maintenance' started by cmtullis, Feb 19, 2012.

  1. cmtullis

    cmtullis 2007 Gheenoe LT15.

    I thought that might get someone's attention. ;)

    No, I ain't suff'rin' from E.D. nor ennythin' lahk that. What I do have a problem with is mah 25HP Johnson 2-smoke. Seems that when the wife an' I took our LT-15 out to run around a bit on Lac du Lanier up here nawth of 'Lanta, Georgia, we could only tease about 24 MPH out of her at WOT.

    Now my wife, Meaux, thinks that this is all just well an' good since she was in the pilot's seat yesterday an' was quite content with movin' at 24MPH at the top end. However, I recall, very distinctly, gettin' GPS readings in the upper thirties when we first strapped 25 horses to the back of the 'Hoochee Queen a mere ten months ago. Heck, we even got one reading of 42 MPH! (But that was a-headin' downstream on the Chattahoochee River with a four knot current helpin' to push us a bit.)

    I have noticed (as has Meaux) that when the throttle is advanced, there is a lot of free movement before she starts raisin' the rpm's an' spinnin' that propeller as she should. She's currently set up with a console and remote steering, an' I'm jes' a-wonderin' if mebbe I need to git into the throttle-box an' check to see jes' how much play there is in them cables leadin' to the throttle a-fore I go off an' git to tinkerin' around with the motor itse'f.

    I did adjust the idle setting screw next to the motor in order to lower the RPMs at idle jes' a little bit, but I jes' cain't imagine that an adjustment there would have an impact of better than ten miles an hour at WOT.

    Enny idears, y'all? I would really, really like to git them ten or twelve MPH back in despite of what Meaux has to say about it! Does it sound to ennybody else that there might be jes' a might bit too much play in the throttle advance lever afore it comes to gettin' the ol' girl to move, an' that mebbe that would limit the overall top end speed also too?
  2. Brett

    Brett > PRO STAFF <

    Check range of motion of the throttle at the carb with and without remote cables attached.
    Check for play in the control cables and that the cable ends are still snug to the core wire.
    Verify that the cable ends have not slipped on the core wire. Only held by a set screw.

  3. HighSide25

    HighSide25 Well-Known Member

    I am all for the south, and love the TV show "Swamp People", but come on man!

    I just got a dang ol' whatchamacall-it head throbbin like you you you you shot off a 10 gauge too close to your ear wife nagging atchya all da time an dat truck be breaken doen on ya so ya bust yo nukles up to tuwn a rench an seemin' to always git a bloody nuckel cuz o' it.... yeah, one of dem der uhhhh....uhh

  4. cmtullis

    cmtullis 2007 Gheenoe LT15.

    Brett, I b'lieve that was the ticket. I jes' needed to do a thorough check of all the set-screw connections to the cables an' make sure they were cinched down good an' tight. Obviously, there were a few minor adjustments to make also too, since I had to git the throttle control pushin' cable from the git-go rather than gittin' better'n half-way forward afore enny diff'rence was noticed. Of course, I 'spect I'll have to do a wee bit more fahn tunin' on the water this weekend since a body cain't attain perfection in the garage.

    I am right indebted to you, Brett.

    Now, CT. I cain't unnerstand a lick of that jibberish you posted. It 'pears to me that you must've been smote in the head somethin' fierce. Quit stutterin' an' come on out with it, mah friend.

    As fer the migraine headache you state you get from readin', jes' try not to rush too fast through the words. It's a lazy, hillbilly accent that one is s'posed to saunter through rather than trot or jog. Despite the name, I am only an honorary coon-ass.

    I do thank you fer the advice, an' I shall continue to refrain from postin' too often in sech vernacular. However, sometimes the bug jes' bites me awful hard, sorta lahk one of them yaller flies in the Okefenokee, and it is more'n a struggle to resist the temptation. (But I never slur mah words. No matter how many snake bites I claim fer the day. ;))
  5. mark_gardner

    mark_gardner I Love!

    i can believe 30-32 but 40 + mph out of a 25 hp?.... if thats so i need a tune up :eek: :)
  6. cmtullis

    cmtullis 2007 Gheenoe LT15.


    Keep in mind that the 40+ readin' came from our GPS while we were headin' downstream during a release from the dam upstream. That coulda made fer a diff'rence of ennywhere from 4 to 7 miles an hour on the GPS readin'. So, after review of the data, an' considerin' the conditions, I reckon the best accurate readin' I ever got in still water would put me in the mid-thirties at best when I'm the onliest one in the boat.

    So, yeah. The 42 MPH readin' is correct, but it's sorta lahk figgerin' an aircraft's top speed an' includin' a favorable tailwind in your calculations.

    An' Brett. . . Don't you go a-thinkin' fer a minute that I ain't seen you hollerin' at us to quit squabblin' over a measly forty mile-an-hour, an' your mention of hittin' 80 MPH with your 9.9! (And on I-95, no less! ;)) I jes' wasn't in a position to do enny typin' at the time, because I wanted to ask you what kinda prop' you were usin' when you was a-runnin' that boat on the Innerstate! My propeller gets busted all to Hades ever' single time it hits asphalt! :D
  7. Brett

    Brett > PRO STAFF <

    Y'er hitting the asphalt?  :-?

    There's the reason y'er only gettin' a measly 40...
    y'er boat's sitting too low on the trailer!
    When towing ya' gotta keep that skeg an' prop from scrapin'!


    Tha't 'splains all the gouges in the pavement I saw the last time I passed through y'er neck of the woods.
    Here I wuz thinkin' some farmer had been draggin' his harrow down the road.

  8. Rooster

    Rooster Towee Calusa

    No, my friend Swamp Angle had thrown one of his empty flagons on the floor of the car and it was stuck under the gas pedal, preventing him from mashing it harder!
  9. Chris_Smith

    Chris_Smith Id rather be fishing

    Too good not to read all the way through. Go back and read it again... :) I think your on the right trail with the throttle linkage check for play and adjust. Good luck.