porpoising question, Carolina Skiff J-16

Discussion in 'Boating' started by Bill in SC, Apr 13, 2008.

  1. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    Actually I have two questions. My Carolina Skiff J-16 jumps out of the hole like a banshee and planes out immediately, but unless I have someone sitting on the bow, it starts porpoising, even in the lowest motor setting. Will a whale tail eliminate the porpoising? Also, the torque on the 25 hp Tohatsu is incredible. I can run about a half mile wide open and it about pulls my arm off. I have to keep stopping just to rest my arm! Is there any sort of torque stabilizing device you can run with tiller handle motors? Thanks in advance for any ideas.
    Bill in SC
     
  2. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    I guess what your talking about as far as torque, is a pull to the port or starboard side while underway. Actually, your in luck - if that's the condition. on your motor, just above the prop is a little fin. When you look at this fin (by the way, it is called a trim tab) it is a part of a round circle, held onto the motor, usually, by a 5/8" bolt. While on dry land, the motor in the down position (just because it's easier to adjust this way) loosen the bolt and turn the back of the fin in the direction that it is pulling (try measurements of about 1/8"). Tighten the bolt and give it the water test. Still pulls, adjust the tab some more. Keep making the adjustment until the motor runs straight. Whale tales probably would help on the porpoising. A well balanced load would probably work wonders also.
     

  3. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    AwShucks: I tell you, as many boats as I've had, I should have thought of the trim tab. This Tohatsu looks different than most. Are you referring to the small item that is held on by the screw here in this pic? The boat is pulling to the starboard side. I appreciate the help! BTW: I hear ya about the balance. I do have, me, 2 batteries and 12 gallons of gas in the rear. That's the only way to keep my boat space freed up for fishin'.
    BB in SC
     

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  4. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    That is a secondary water inlet. If you don't put tape over that, when you run it on a hose, you'll over heat.

    You don't have, what most folks call, a trim tab on that engine.
     
  5. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    It was just brought to my attention that perhaps the trim tab corroded off. The motor did see a lot of salt activity before I bought it. The rear bolt IS very corroded and it looks as if there may have been a piece that could have been attached to it. Perhaps some other Tohatsu owner will see this and know. Either way, I'm off to research this and see what I can come up with. I appreciate all the very helpful replies!
    Bill in SC
     
  6. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    That's exactly what has happened! I found that the trim tabs do corrode/erode and they are supposed to be replaced when they are 2/3 eaten away. See pic. Should be an INexpensive part. My next dilemma will be loosening the corroded bolt that holds it on.
     

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  7. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    You could soak it good with PB blaster and loosen it up or try some mapps heat or just take a sharp chisel and chip it the rest of the way off as its almost gone anywho.
     
  8. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    I'm wondering if this tab also serves as the sacrificial anode on this engine? The tab and the anodes are listed together on the web page, and I cannot find a sacrificial anode on my engine. BTW: The stainless bolt came right loose. I'll try and score the tab this week. Otherwise the engine is GREAT. Has great compression, cranks easily and runs like a scalded dog. Cranks easily manually too. I appreciate all the leads on this! I hope the tiny tab will turn this old Chevy into a Cadillac to operate! :)
    Bill in SC
     
  9. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    They are one in the same. Omc billed it that way for years and mercs are the same to but merc later added another anode to their engines.
     
  10. Bobpaul

    Bobpaul New Member

    Messages:
    3,039
    State:
    Supply NC
    Yup, it was corroded off. Forgot to add that to my reply.

    When you get it back on, turn it fully in the direction you want to correct. I doubt you'll need to trial and error much.
     
  11. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    I got the bolt out easily enough but the tab was corroded to the lower unit. I applied a little heat and it came out. Called Allen's Marine in Florence and they had one in stock. That little three or four once piece of zinc/lead is $25.45!! :-( Should have it installed by this afternoon. I 'preciate all the help, folks!
    BB in SC
     
  12. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    Got the part and got it installed, tested and adjusted. MUCH better now! Odd thing though. I gave the parts guy my motor model number and he fetched the part. However, the base of the part that fit into the lower unit was DIFFERENT. I had a ROUND hole where the original part fit, and the new part had a half round, half diamond shape. The parts guy said there was only ONE that fit my model/year model number. In fact, the part he gave me covered several years. So.... I had to modify it. I just ground off the diamond end that was on it, and it fit right in there. Really, really strange though. Took me about five tries to get it set just right.
    BB in SC
     

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  13. Stubby

    Stubby New Member

    Messages:
    208
    State:
    Kansas, Ar
    sounds to me like the lower unit may have been replaced.
     
  14. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    Hmmm... never thought of that. You mean to tell me that another model lower unit could possibly be compatible with my model? Just wondering. I'll check all the bolts tomorrow and see if they look like they have ever been removed. 90% of the time if a bolt has ever been out, I can tell just looking at the head of it. I appreciate that idea.
    Bill in SC
     
  15. Pacman

    Pacman New Member

    Messages:
    141
    State:
    South Carolina
    Try adjustments on your motor before you spend money. I lowered the tilt of my motor to bring the bow down when I'm alone in the boat. Now the bow is lower and it planes better, but I also created the porpoise feeling. A little MORE tilt in your case might lower the back of the boat and be more stable.

    I also had the problem of the torque wearing me out. I tightened the collar that adjust steering tension and it helped a lot. I'd rather exert a little more effort when changing direction than tolerate a constant pull the whole time.

    May not help, but it's free to try.
     
  16. Pacman

    Pacman New Member

    Messages:
    141
    State:
    South Carolina
    Try adjustments on your motor before you spend money. I lowered the tilt of my motor to bring the bow down when I'm alone in the boat. Now the bow is lower and it planes better, but I also created the porpoise feeling. A little MORE tilt in your case might lower the back of the boat and be more stable.

    I also had the problem of the torque wearing me out. I tightened the collar that adjust steering tension and it helped a lot. I'd rather exert a little more effort when changing direction than tolerate a constant pull the whole time.

    May not help, but it's free to try.
     
  17. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    No need to worry about adjustments in this situation, Dewayne. The trim tab is an important device on the motor and mine was corroded away! GONE! After replacing it today the boat steers effortless now. The porpoising is still present and I have tried all the settings on the pin at the motor. It's simply a matter of my weight distribution. I like the weight like I have it because it frees up the whole floor of the boat for fishing and not dodging stuff when fighting a fish. As long as any adult is sitting forward it does NOT porpoise at all. If I go fishing alone, I simply move some of the "stuff" forward to compensate for it. Also, when I start fishing for flatties, I will have my 150 quart aerated cooler forward and that will also compensate for the porpoising. That being said, the whale tails are inexpensize, and if it would keep my boat down with the set up I have now, I'd like to install one. Then, I'd have the best of both worlds. I promise it won't porpoise with you in the front of it Wednesday!! :big_smile:
    BB in SC
     
  18. MoMudCat

    MoMudCat New Member

    Messages:
    186
    State:
    Troy,MO
    Bill, let us know if the whale tail thing works. My boat does the same thing, except, it only does it when I trim the motor out to run fast. If I have someone in the front I can trim her out and run without the bouncing!