Project "Knot Sure"

Quote:

---

Originally Posted by OLEGATOR

never ran with low water pick up. no need for choppers or cleavers at the height i recommended as there are better props nowadays. with 2:1 gearcase you should run about a mile per hundred rpms with a 23" pitch merc prop. your listing problem could be a bottom problem.

---

Thanks for the info.

At the height your suggesting, wouldn't I require a jack plate using this long shaft outboard? (Obviously not a 10" setback)

As for the prop, Would this 800 be able to turn a 23" pitch prop to 5500 rpms?

As for the listing, It reared its ugly head as I did 2 things, removed the jack plate and moved the fuel tank up front which would have moved the center of this boats weight quite a bit forward. I would think now trying to balance more of this weight on the deeper V on the front of the hull vs the flatter V aft. I am hoping moving this weight back aft will make this go away. I think I will take your advice and move the battery as well prior to next run. I feel like I should be changing one thing at a time, but I also think that I should just start over with everything where it belongs in the first place.

Edit, Had some time today before going to my kids house for dinner, so I moved everything back to the back behind the seat. Now the wait for some reasonable weather to run her again.

Attachment 518090

Quote:

---

Originally Posted by fatlenny

Thanks for the info.

At the height your suggesting, wouldn't I require a jack plate using this long shaft outboard? (Obviously not a 10" setback)

As for the prop, Would this 800 be able to turn a 23" pitch prop to 5500 rpms?

As for the listing, It reared its ugly head as I did 2 things, removed the jack plate and moved the fuel tank up front which would have moved the center of this boats weight quite a bit forward. I would think now trying to balance more of this weight on the deeper V on the front of the hull vs the flatter V aft. I am hoping moving this weight back aft will make this go away. I think I will take your advice and move the battery as well prior to next run. I feel like I should be changing one thing at a time, but I also think that I should just start over with everything where it belongs in the first place.

Edit, Had some time today before going to my kids house for dinner, so I moved everything back to the back behind the seat. Now the wait for some reasonable weather to run her again.

Attachment 518090

---

do to my very poor composition skills along with even poorer computer skills, it would be better if you pm your phone # and i would be happy to answer any questions you may have.

Another test run and found that the Sierra speedo shows about 5 MPH higher than GPS at 40mph. Is there any way to calibrate these water pressure speedos?

Found a Michigan prop 12 5/8 X 21P prop for $25 on market place. Looks like it never had been used. Purchased it for testing as it was cheap as heck and had to be an improvement to the 15P prop that came on the motor. Moved my jack plate (purchased a 4" set back) all the way up putting my prop shaft about 4.5" below the bottom of the boat. (I have the motor mounted to the top holes on the jack plate, so could go higher) Got her up to 43 MPH GPS and had a cool looking rooster tail that I could see from my POV. Water was still peeing at this height. It seems I lost quite a bit of bow lift with this set up. I believe raising it may get me more speed, and may need another prop to see any thing more than a MPH or 2. With this prop I was seeing some lower RPMs until I trimmed it up. I could find a sweet spot to get her to hold at around 5500 doing 42 to 43 MPH.

My questions are about how prop pitches and ventilation with raising the motor works and bow lift. I would expect the higher you pull the motor up, the more ventilation you get. So with that being said, is the higher pitch required to compensate for the ventilation you get running your motor high at high speed to keep your RPMs in optimal operating range? Or am I looking at this all wrong? What is suggested at this point to add a bit more bow lift? Looking at the spray, It seems that she needs a bit more lift that I cant get at this height, and this prop. All movable items previously moved to the bow has been placed back aft. This hull does have a hook.

Well I did it. I replaced the 80 with a 1979 1/2 115 long shaft. Talk about a blast to drive now. She instantly jumps right out of the water and onto plane. with the Michigan wheel 071038 12.625 x 21p aluminum prop and the motor adjusted with the cavitation plate just above the bottom of the boat, she only hits around 44 to 45 mph but only if trimmed up to where the prop is about to blow out. if I trim it down a little I cant get above 5k rpm at about 40ish mph. If I bring the motor up I can get a little more mph but this prop doesnt grip and the rear end gets squirrely. not chine walking yet, but feels like the rear is about to slide out. Like im riding on ice. Now I understand I am probably not going to get 60mph safely out of this little boat but I would like to get into the low 50s. Is it all in the prop going up in pitch along with raising the motor? I ask because with motor mounted with anticavitation plate in "normal" running position, about 1" above the bottom of the boat, I cant go above 5k rpm, and I know leaving the motor in this position is good for normal use but if I want to go fast I need to raise the motor up. and advise appreciated.

Well here we are again. Some new parts and new issues.

Got a LaserII 22 pitch prop, only used once, paid $100 for it on marketplace. not a scratch on it. Got the Prop mounted and she sure looks purdy.
Attachment 520112

Well got home today and decided to move the jack plate up all the way gettin her ready for some testing tomorrow after work. Moving the jack plate up I saw something funny. Well not funny, but not right. Decided to look up reviews on the jack plate I bought off Amazon, and reconfirmed this jack plate was rated for 225hp max. I should have had no issue with my 115 right? WRONG! There must be some translation error from the china made jack plate. Maybe it was a typo and it was suppose to be a 25hp not 225. LOL. Well contacted Amazon ready for a fight because it was past the 30day return date. But to my surprise, they helped me out and got my refund going. I went back and looked at the reviews again because I seem to remember seeing mostly positive reviews, then I found the one hidden all the way at the bottom. This guy almost lost his outboard because his broke the same way mine is about to.

This is what mine is looking like, stretched out about to break.

Attachment 520113

This is the reviewers that actually broke.

Attachment 520114

Now I have a few options, but I dont want to mount the outboard directly to the transom as it is the older bolt pattern and I would have holes to plug up.
Either im looking for another 4 inch set back jack plate that will work for me without breaking the bank.
I could just put the 10" back on it.
I could grab the jack plate off the bass boat. Not sure if that one is 4 or 6 inch set back but a much thicker aluminum and on the down side, not easily adjustable on the water.
Or finally I could use the brackets to build a transom riser like BOB'S sells. Only down side to this is the adjustability is not there at all.

Well tomorrow going to pull the jack plate off so I can get it returned, and hang the motor on the transom just temporarily till I figure out what path I am going to take. If anyone is local to Flint MI and has a 4 inch manual jack plate they want to sell or trade up for a 10 inch, Hit me up!