Posted: 7/18/2008 9:32:48 AM EDT
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I should preface this with the fact I don't know much about boats.... My dad has an old boat with an outboard Johnson 115. He had some work done to the rear of the boat to add support for the motor. Since the work was done, the front of the boat sure pops up out of the water under speed. Which direction do I need to move the angle of the motor to level it out. Toward the boat or away from it? I swear if I move it the wrong way the boat will flip backwards  maybe not, but I just don't want to mess with it too much
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I did a quick search and they run around $450. This would double the cost of the boat.  Anyone have any info? The motor can be angled differently by pulling a pin and adjusting the position. I just want a little clue what direction to go because it can sure be a pain to move around while the boat is in the water. With my luck I would be dropping the parts to the bottom of the lake. 
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Look at the motor and you will see a rod that goes through different holes and change the trim limit on the motor. Move that rod (about 8" long) one hole towards the rear of the boat. Try again and see if it corrects your problem. Rule of thumb is you want to take off with the trim in all the way and once on plane you want to trim out to raise the bow. If you do not trim out you will spear the waves in the water and the boat will be unstable. |
| You don't need trim tabs unless its an offshore or going to be on big water. Most off shores are I/O (Inboard/Outboard) so trim tabs make minimal difference, the height of the bow is adjusted my the power trim on the out drive. You need to bring your motor closer to the rear of the boat - closer to 90 degrees. |
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Thanks everyone. Like I said, prior to the work being done it seemed great. Then they added an aluminum brace on the transom? and I think it changed the angle of the motor enough that the front end just won't stay down. You have to stand up to see over the front. The boat is mostly used for trolling with a smaller motor, but getting across the lake isn't what it used to be with the larger motor. |
not exactly....tabs are used for all types of purposes....... i have tabs on my 16 foot flats boat......and it's never in "big water" tabs makes HUGE difference in a boat and are worth the money |
The shop he took it to custom made an aluminum plate for the boat. You think the motor needs to be lower on the boat? or will the angle fix it? |
The work done to it only added the thickness of the aluminum to the height of the transom. If anything, it should have only added 1/4" height. |
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OK, without trying to get to technical. Just above the prop there is a horz. plate called the cavatation plate. When the motor is trimed down that plate should be level or just above the lowest part of the bottom of the hull. If it is on a tralier use a string line along the bottom of the hull (keel) and see where the cav. plate is. |
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www.associatedcontent.com/article/811915/howto_guide_for_boat_outboard_motor.html read this... it is all you will need.. for about 75 bucks you can solve the issues. |
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I'm a believer in when you make a change and it doesn't work undo the change. If I am reading this correctly all they did was add a aluminum plate to the back of the boat where the motor mounts to reinforce a weak transom. If that's the case then no angle should have changed unless they installed a wedged shaped reinforcement plate and that's not likely. You shouldn't have to undo that. It worked before and it should still work now unless that aluminum weighs a couple of hundred pounds and I doubt that. It still sounds like the motor is not trimming in far enough. A picture here would be worth a thousand recommendations. The idea if trim and tilt is for you to be able to launch and get on plane quickly and then adjust the trim to optimize performance of the boat according to the weight load at the time. Please check to see that your motor is trimming all the way in. Your transom should be angled from top to bottom with the bottom of the transom a few inches closer to the bow. The motor should be able to trim in enough that it is parallel with the transom angle. That means that the prop should be forward of center. Adding gullwings or trim tabs shouldn't be necessary if everything is set up correctly. It worked before and it should work again. If necessary you should take it back to the guy that did the work and let him look at it. He may spot the problem immediately and save you a ton of money on unneccessary add-ons and gizmos. FWIW a properly installed gullwing won't be in the water once you are up on plane, it is only a assisting device to get you up on plane sooner so if your still having problems once on plane a gull wing won't correct your problem.. |