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Discussion Starter #1
I know that this has been brought up before in the past but I am looking to get some help. Just re powered my Pathfinder 15t with a new Suzuki and trying to get motor height issues resolved. From what I have gathered I think the motor may be to low, when i get on plane i am getting alot of spray on the back of the boat and cowling. The spray is shooting out of the sides coming from the front of the lower unit. If I trim high enough for the spray to go away, the motor sounds like it is starting to cavitate. Also going along with that i have gotten some porpoising and used trim tabs to correct that. From what i have seen researching the topic, the symptoms seem to say the motor is to low. But I am also making a big change I went from a lighter 2 stroke to a much heavier 4 stroke. Just for info i am running a 14p 4 blade that is 11.5 diameter, and not running jack plate. If anyone could give some advice on proper height for tunnel hull, maybe even some pictures of a similar setup so i could have a reference point to where my motor should be i would really appreciate it.

thank you in advance.
 

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Discussion Starter #4
Just making sure I am doing this right, when checking height boat should be close to level, and get the motor where cavitation plate is level? Not trimmed all the way down like I would before I would i was trying to get on plane.
 

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Discussion Starter #6
A937F1BD-B844-4016-8EFB-4AEC78071574.jpeg The Suzuki 50 only comes in 20 inch shaft. This is about propeller height with boat level and cavitation plate level as well
 
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Looks close, raise it a hole at a time until it cavitates then drop it a hole.
 

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I have a Tailfisher with a 60TLR 4 stroke Yamaha.
No jack plate
My cavitation plate is above the tunnel.
Also, mine planes much quicker if I start with the motor upright. If I tuck it, it takes three times longer to get on plane.
I leave my trim tabs up almost all the time.

Disclaimer, I do have a 24v trolling motor and two PC 1500 batteries up front.
 

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I think you can probably get away with raising it two holes. My 17T with a 4-blade runs best in the second-to-highest position.

Also, which prop is that specifically? I'm running a PT SCD, which isn't an especially grippy prop. If that's a PT SWC, you might be able to go even higher.
 

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Discussion Starter #14
It’s actually a solas prop, I tried powertech swc3 and due to diameter I had a lot of slippage and was getting way to high of rpm. The solas is what my mechanic recommended and it was also the largest diameter shelf prop I could find. It’s a 11.5 diameter 14 pitch. Box describes prop as great stern lift, handling, and speed/efficiency in the engines mid range.


Next time I get a chance to run it I will try with motor upright thanks for the advice. I have 18 gallon gas tank up front only thing in the back is cranking battery. I don’t have trolling motor at the moment.
 

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I'd raise it two holes and give it a shot. On takeoff, I find quickest to plane is tabs down about halfway and propshaft horizontal. That transom is angled so much that with the motor tucked all the way in, it's almost like you're trying to lift the stern vertically at the expense of forward thrust.
 

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Discussion Starter #17
One last question when taking off with motor level, I would assume once your on plane there isn’t trim adjustment because motor is already where it needs to be?
 

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usually the tunnel puts
IMG_20171014_172041.jpg
up a bulge of water. I would think you would want the prop shaft near the top of the tunnel. Mine is a different design but I can run with the prop almost halfway out of the water, which is where the SWC4 really shines. I have my motor all the way up on the jack plate and drilled new mounting holes in the jack plate to get it mounted higher. I'm not even using the standard bolt pattern. The Hatsu 50 has drain holes all over the lower unit that take in water also, don't know if the Suzuki will cool at that height.
 

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here's a vid of a 15T running on plane, he's got the motor pretty high up. its all about the cooling intake and prop cup though.

 
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