having trouble, new motor, boat doesnt agree with
 

Hello long time reader first time poster ,so i have a 89 powerplay conquest 230 for 2 years now bought with a 454 mag did 58 with tailwind but all the time 56 mph boat . Well last winter got the itch that happens to most of us and looked into more power ,long story short ended up with gen 6 502 bored 30 over full roller 9.5 - 1 comp 850 holley, motor builder says between 525 550 est hp without dyno, anyway all summer long changing props get her up too 69 gps best so far but loose in the rear and 5700 rpm with 23 mirage plus, but when put weight in the boat i have a real hard time getting on plane no matter what prop i try i can easily blow it off without hardly givin it throttle, i have to ease it on plane and roll into to supper slow or iam srewed and have to set her down and try again, this is getting very annoying especially after all the coin i got in it. Iam wondering if i need to space down the drive because its goin much faster now and the boat is ridin way higher at wot. 4 blades shove the nose right down in the water and slip ,3 blades i get the bow lift but slip bad but are faster , 5 blades dont slip near as bad but 64 isnt what iam looking for but only tried 1 5 blade i think it was a 22 or 23 with an exreme cup 64 at 5000 rpm. Iam just stuck not sure exactly what to do , always want more speed but sliping this bad isnt getting job done. Bravo one drive , i believe 1.36 but will know for sure tommarow pulling drive after winterize. Any thoughts ,iam sure other people have been through this.

I find it hard to believe a 4 blade shoves the nose down and slips. What 4 blade? Verify a 1.36 drive. A 1.5 would be easier to work with in my opinion. Have you tried a Rev 4 prop?

Perhaps CG to much in front? Where it is?
Perhaps hook on bottom?
Perhaps both problems?

There is much more to props then blade count. are you trying round ears or cleavers? rev4? hydromotive? B1? Mach?

Ive tried bravo 22 4 blade,bravo 24 4 blade , and a bravo 26 4 blade , also i beleave it was a revolution 24 4 balde the blade design was alot different i will have to check my notes when get home. As far as 3 blades mirage plus 23, mirage 23, mirage 25 modified cup ,mirage plus 25, a torrent 23 , apollo 23 thats on it now that prop place has beating cup in and out of it for a couple months or so now and that prop is terrible. I dont remember the name of the 5 blade i tried but it had heavy modified cup

I know that there ia alot to props ive been using a local reputable company changing the cup and rake on this apollo so far with alot of changes but no matter what blowing it right off and having trouble gettin on plane with a load. I have tried one clever didnt like it at all, all the rest were round ears, except this one michigan wheel i tried ih the ballastic thats it. I have had alot of people scratch there head when i tell them what 4 blade props are doin to my boat but thats whats happening for sure bow shoved down steen lifts up cant get speed like that.

I will verify drive tonight, after work on boat

What was your original prop and how does it perform with it?

Padraig

Orignal prop with old motor was a 21p mirage 3 blade, with new motor that prop was first thing i tried had to feather it on plane can blow it out at any speed when finally got rippin i stopped givin it throttle at about 56 5700 rpm still had a lot of throttle left but didnt want to push the rpms up to high i beleave i was goin 63 or so ,but that was the first thing i tried so that was in early may

My boat has 8ft beam and is heavy for the size i beleave iam about 4000lbs.my best prop try so far was mirage plus 23p 56 5700 rpm at 68 69mph gps, but could blow it out at will and was a bit loose up top, think the blade tips are to close or breaking the surface of water but not 100 percent sure

first. why would it have a 1.36 drive? I cant imagine any one setting it up with a 454 mag and a 1.36 drive as it would be a dog. second, 69 mph at 5700 is around 25% slip with a 1.36 and around 16% with a 1.5 ratio which seems more likely.
the part I dont understand is if the boat ran good with the original setup and all that changed was the increase in horsepower then it should run the same now but pull more rpm. the boat handling as far as getting on plane and any speed up to the original mid 50's should not change. the only reason it would blow out now getting on plane is if the motor makes no bottom end power and has to cavitate the prop to get the power up. that should not be an issue with 500 odd horsepower.

as said above - If the only thing that has changed is HP then It wouldn't change getting on plane. Should blow out the same with either engine.
More HP will just mean more RPM and speed. The engines weigh the same so no change in CG. Unless you changed from stock exhaust to tubular headers.
And for top speed the tips of the propeller blades MUST break the surface to free up the prop. How far below the hull is the center of your prop shaft when the prop shaft is parallel to the bottom of the boat?

Did you add a drive shower when you upped the HP and then started having this problem ?

Ok guys prop drive is 1.5 for sure just pulled it, i dont know why all the slip getti g on plane i assumed because of more hp and torque, center of prop shaft to bottom of boat is 8.5 inches, i did not add a drive shower still running same one as last motor and same drive, the previous motor never blew the prop off never cavitated, but this thing is bad , happy ish with speed when i get it there but went on poker run added 2 guys took me 4 times to get on plane it cavited so bad on take off if you dont baby it to the extreme it will cavitate so bad you have to set her down and start over

Same exhaust as well

And i agree no weight change, and i appreciate your guys feed back on my issue, just got done pullin drive and carb after winterizing.

Compedgemarine if i could get traction this thing would be a missle getting on plane, i dont understand why iam slipping so bad

Coupler bad, slipping getting on plane?

Curious to see what is gonna fix your problem!

I orignaly thought that but thats not the case, it just blows prop free , complete lose of traction when u add any type of power

Put up a current )this year) a pic of your drive showing the pick up part of the driveshower.

Trying to figure out how to post pics of shower

My thoughts also.....something besides hp has changed.

Padraig

8.5 inches below the bottom - NO WAY it is cavitation or blowing out getting on plane.
Something else is wrong.
4 blade prop is worse because it puts more load on the drive, coupler, clutch causing the problem.
No way it can be blowing out. IT has to be something else.
Any chance he has the celery sticks installed wrong?

if your 8.5" deep, that is not the problem. Do you have the trim spacers? put them in backwards??

The rear of the drive where the trim rams mount is the hole where the shaft goes through round or oval?
If oval do you have the celery sticks in front or in the back. They should be in the front.

BTW... I did not steal Tinkerers thought, he just typed faster lol

I can get on plane with my prop shaft 10.5 inches higher than his. Were missing something.

I dont know what you mean celery sticks, were the trim cylinders mount are round with the rubber tapered bushings

8.5 inches deep = NO way a drive shower add is going to cause this problem.

The hole in the back of the drive where the shaft with the rubber bushings goes through is round not oval?

A 4 blade isnt worse slip ,it slips less but can still spin it at will the main problrm runnin 4 blade is the stern lift , it pushes bow down and cant over come this even with trimmin he** out of it.... too much boat in water... 5 blade doesnt slip much at all but like i said only tried one and it was heavy cupped and seen 64- 65 5000 rpm didnt see the speed i would like bit yet didnt mess with 5 blade too much, sorry iam slow guys, just measured were shower comes thru cavition plate sticks down about 1/2 in cant see that doimg it especially since its been on there for years

A 4 blade isnt worse slip ,it slips less but can still spin it at will the main problrm runnin 4 blade is the stern lift , it pushes bow down and cant over come this even with trimmin he** out of it.... too much boat in water... 5 blade doesnt slip much at all but like i said only tried one and it was heavy cupped and seen 64- 65 5000 rpm didnt see the speed i would like bit yet didnt mess with 5 blade too much, sorry iam slow guys, just measured were shower comes thru cavition plate sticks down about 1/2 in cant see that doimg it especially since its been on there for years

I doubt that you are getting stern lift from the 4 blade prop. You have to be surfacing the prop to get stern lift. As the blade enters the water again as it goes over the top it pushes up on the drive. More blades means more lift. More cup in the prop = more transom lift.
The higher the X the more lift.
I had to cut the bell off on my prop to lessen the transom lift. IT WAS A VERY noticeable improvement on my boat.

I bet u clutch is going bad ,,

Tinkerer i beleave your asking about the holeas and shaft were the trim cylinders mount they are round with the tapered rubber bushingsto mount the cylimders

The weight didn't change, The drive and prop didn't change. Adding HP wouldn't change getting on plane if you were easing into it.
something else has changed.
Do you store the boat outside?
any chance it has taken on weight somehow? water in areas you can't see.
What you are saying it sounds to me like you added weight to the bow somehow.

I appreciate the post but if clutch was bad i would have same if not worse problem runnin a 5 blade and the 5 blade gripped well was just slow, took off like crazy tho, i can only describe what is happening i dont know y the 4 blade makes it nose down i thiught because it caused stern lift , i could be wrong on y its happening but iam not wrong on whats happening thx

I understand y u think that, boat stays out of water , stored winter inside barn, outside during summer in driveway with cockpit and bow to stern cover on it, with nose in the air and plig out after each use,i live 2 blocks from lake st.clair in michigan, motor built by dynamic speed and marine, boater my whole life but first boat with any power to talk about, just givin you guys background not sayin anything negative, since weve been talking bsck and fourth ive been out to boat with flashlite 3 times lol, thx

I tried a cleaver type prop once, boat popped right on plane, but had no bow lift whatsoever, boat bowsteered scarey...