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MOTOR PLACMENT

crowhater

crowhater

Well-known member
My boat runs flat in the water and I need to fix the problem. If I put weight in the rear of the boat it runs much better but still runs flat. I have dual trim tabs so I can trim the nose down if I need to. The problem I have now is that the faster I go the ligher the boat gets in the rear and it will spin out on me. Once you hit around 40MPH the boat starts to feel unstable with no load. If I have 5 guys and 6 dozen decoys I can run up to 50MPH before the boat starts to feel unstable. It is 18" from the back of my boat to the back legs of the engine stand and 61" from the center of my hub to the bottom of the boat. My boat is an 18X7 with side by side control seats and a front bench seat. I run a 50gal fuel tank under the motor as well as dual batteries. My trim tabs point almost strait up unless I lower them so they do not make drag. I can attach pictures if anyone can tell me how to do this. If I change the angle of my motor will this make the boat stop plowing the nose? The motor is mounted level right now.
 
I would say putting some spacers under the rear of the engine would kick the nose up for ya. Start with a little lift and add as needed. Good luck,let us know what works.
 
sounds like your boats set up right any boat over 15ft is gonna be nose heavy just physics i once had a 15ft airgator 500 1.77 boat ran scary on its nose i fix the problem with bottom jacks sorta like a reverse step hull
 
Shimming the engine is a very fine adjustment, it probably won't make a lot of difference

Adding weight to the rear is really just pushing the stern down rather than lifting the nose

You probably need to look at how your boat is riggged and what shape your bottom of your hull is in, but Plum is right, it's always going to run a little flatter than a shorter and lighter boat
 
The bottom is in perfect shape. I have installed one jack under the control seats just behind them. I put about 1/8" of down turn in this jack. Tomorrow I am going to make a grass rake for the boat to add lift on the front end. I bought a sheet of 5x10x1/8" aluninum for this job.
 
I have a 15 x 7 aluminum boat and have a bunch of down push on my bottom jacks. Just try riding and adjusting then riding again... you should notice that as you add jack to it the bow will start to rise.
 
YOU could also move the stand back about an inch. That will certainly solve your problem.
 
EVERY BOAT IS DIFFERENT HAD THE SAME DEAL ! MINE NOW RUNS ON THE BACK 5 FT ! SPACE THE MOTOR UP IN THE BACK LOOKS WEIRD EVERYBODY SAYS TOO MUCH !BUT LOOK AT ME RUNNING ! DRY RUNNING IS GOOD ! MUD RUNNING IS GREAT ! DEEP WATER COOL ! 16 BY 8 KENNEDY !IT GET UP FAST ! :D
 
I moved the motor back two inchs after I first set up the boat and this helped alot. Now I am looking at moving it back another two inches and this will put the back legs of my engine stand 16" from the transom. I have had some people tell me that this is a waste of time because 2" on an 18' boat will do nothing for me. I know for a fact that the boat handles 100 times better if I have 50 gals of fuel and all the weight in front of the cage. The boat will also make better fuel milage when I keep the weight in the rear. I want to make the boat ride heavy in the rear because I can level it out with the trim tabs.
 
You are answering your own question, go ahead and move that stand back more worst case scenario you'll start porpoising a little which is what you really want. :D
 
Make sure that you dont have a hook in the bottom. sometimes it is a very small hook "dent" thats all it takes to make the nose dive into the water. I had the same problem that I had to fixed by taking the dent out. It was a real chore we had to remove the rigging and we used a back hoe bucket to push it down. the hook was so small you could barely see it but boy did it make a HUGE difference in th hulls performance. Because it changed the shape of the bottom. We then welded gusets from the transom to the stringers to help prevent that from happening again.
 
I did have a slight bend in the bottom right under the fuel tank but I put a srcew jack in the boat and leveled the hull out. If you look at the bottom of the boat it looks flat as a pancake now. Maybe I need to put more downward bend in the boat.
 
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