Another prop question

You know the drill..

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urbnsr
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Re: Another prop question

#16 Post by urbnsr » Tue Jul 31, 2018 3:21 am

If this is your first Michigan prop, you'll need their hub kit matched for your motor.

What is your motor's recommended maximum RPM? If it's ~6K RPM and you can pull 5800 RPM with a 17 pitch prop, 11 pitch is a big jump. I wonder if you have a spun prop/hub - or something else is not right. My DF90 had a 17 pitch prop and I could only get 5200 RPM. Going with MichWheel 13 pitch prop (in my case) allows me to get to 6K RPM.
Paul

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FLOUNDERPOUNDER225
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Re: Another prop question

#17 Post by FLOUNDERPOUNDER225 » Tue Jul 31, 2018 7:12 am

bansil wrote:
Wed Jul 18, 2018 4:12 am
wwind3 wrote:
Tue Jul 17, 2018 4:46 pm
Tell me about the boat---is it rated for 90---or larger motor? Length, number of toons, weight, etc. If trimming up does nothing-you may be underpowered or too much weight in front of boat, etc..... FYI---I have 20ft Lowe 25in toons, 2 fishing seats up front-90 HP Merc Optimax, Merc SS prop 13 x 16in prop 27mph GPS
no idea on engine, it is original according to titles and paperwork I have
1990 Suzuki DT90

24 ft, 2 pedestal seats up front, no furniture (we use folding camp chairs) normal fuel load is about 15 gallons, 2 batteries, composite deck floor (about 250# more than marine ply and carpet) that about it

vcbd.png
In the one pic tied up at the boat house, it looks like your starboard toon is sitting much lower in the water, it may be the dock lines causing it, just noticed and wondered if you have a bunch of water in that toon?
Pensacola FL
2015 Berkshire 231 RFC
Yamaha F-150

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bansil
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Location: Watâ'gi lake...Beautiful Waters

Re: Another prop question

#18 Post by bansil » Tue Jul 31, 2018 7:55 am

no water in toon, big gas tank in corner (moving it to in front of a new centered console this winter) so most of my wt is there

It sits even when dogs and wife on board :mrgreen:

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bansil
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Re: Another prop question

#19 Post by bansil » Tue Jul 31, 2018 8:03 am

urbnsr wrote:
Tue Jul 31, 2018 3:21 am
If this is your first Michigan prop, you'll need their hub kit matched for your motor.

What is your motor's recommended maximum RPM? If it's ~6K RPM and you can pull 5800 RPM with a 17 pitch prop, 11 pitch is a big jump. I wonder if you have a spun prop/hub - or something else is not right. My DF90 had a 17 pitch prop and I could only get 5200 RPM. Going with MichWheel 13 pitch prop (in my case) allows me to get to 6K RPM.
not sure I have seen 4500/5500, 5000/6000 and 5000/6000 on 3 different charts

I was using a tach that wraps around a plug wire, so not 100% sure how accurate it was

From what I have read the big jump comes from going from 3 to 4 blades (I know big big azz old pontoon won't speed along, I just want more efficient and a couple miles more per hour, I ge passed by 40 and 50 hp boats with furniture and 4 or 5 people on board :cry:

yardbird
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Re: Another prop question

#20 Post by yardbird » Fri Aug 03, 2018 2:48 am

I have an 18 foot with a 40hp. It had a 30hp 2-stroke. Now I have blowout issues above about 2500 RPM. Now... I do have the older U-shaped pontoons so things might be different for the round tubes, but the motor came with a 14 pitch and it was just way over propped. I dropped to a 9 pitch and that made a huge difference. However I'm still blowing out. If I raise my motor so the cav plate is even with the bottom of the transom pod, the boat is barely usable. Blows out at anything above about 1500 RPM. So in my case, I think I need to drop it deeper, which, for me, means cutting the transom down.

Getting your boat propped right is the first thing you need to do. Look at the various prop calculators and find one that is closest to your boat configuration and weight. Go from there. I think the tritoon guys have it easier, but .... and especially for the older toons... we have 2 displacement hulls with a motor plunked down between them. We have wake turbulence coming off 2 hulls and meeting in the middle. Right where the motor is. My boat would have to be powered way beyond its rating to ever have any hope of getting those tubes "on plane".

Just a thought. Gather as much info as you can but unless you're talking to someone with the exact configuration you have, keep in mind your situation may have its own little twists and turns.

urbnsr
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Location: Celina, Ohio

Re: Another prop question

#21 Post by urbnsr » Fri Aug 03, 2018 3:12 am

bansil wrote:
Tue Jul 31, 2018 8:03 am
...
From what I have read the big jump comes from going from 3 to 4 blades
...
When I last talked to Michigan Wheel, they recommended that I reduce the diameter by 1/2" when going from 3 blade to 4 blade. They said the reduced diameter makes up for the additional blade. I'm not sure about the difference from 3 to 4 blade. And, not that it matters here, but earlier I said I went from 17 pitch to 13, but it was from 17 pitch 3-blade to 15 pitch 13-3/8" diameter 4-blade.
Paul

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bansil
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Re: Another prop question

#22 Post by bansil » Fri Aug 03, 2018 4:53 am

Well after talking with propgods and a couple others, i found a NOS--> SOLAS AMITA 4 SD4X13.25X13R 4413-133-13, comes with a suzuki hub for wayyyyy cheaper, box is really faded, prop looks NIB though

It should give me a couple mph but biggest advantage should be more low/mid torque to fight current and wind and should be moar efficient mpg, we will see hopefully next weekend

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bansil
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Re: Another prop question

#23 Post by bansil » Wed Aug 08, 2018 10:03 am

So the man in the brown truck drop this off yesterday
prop1.png
prop1.png (900.88 KiB) Viewed 72 times
prop2.png
prop2.png (595.5 KiB) Viewed 72 times
Hopefully can get it changed this weekend, will I need a puller? of just a rubber mallet?

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wwind3
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Re: Another prop question

#24 Post by wwind3 » Wed Aug 08, 2018 1:40 pm

bansil wrote:
Wed Aug 08, 2018 10:03 am
So the man in the brown truck drop this off yesterday

prop1.png

prop2.png

Hopefully can get it changed this weekend, will I need a puller? of just a rubber mallet?
Do you have a cotter pin holding prop? Usually just remove pin and unscrew the locking nut. I use a block of wood to wedge the prop against the motor to keep it from spinning--no hammers needed probably.
Big Crescent wrench should do the trick
2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS

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bansil
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Re: Another prop question

#25 Post by bansil » Thu Aug 09, 2018 1:18 am

Thanks!, Plan is to stop at boat tonight after work and see what i will need, great hint about wood!

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wwind3
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Re: Another prop question

#26 Post by wwind3 » Thu Aug 09, 2018 4:00 am

bansil wrote:
Thu Aug 09, 2018 1:18 am
Thanks!, Plan is to stop at boat tonight after work and see what i will need, great hint about wood!
U R welcome--here's a short video--sped up but u get the idea.....
https://www.youtube.com/watch?v=dM6Qpix_Hh0
2009 LOWE SS204 25in logs
90 Merc Optimax
Motorguide W55 Wireless
Underskinning
28 GPS

yardbird
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Re: Another prop question

#27 Post by yardbird » Thu Aug 09, 2018 8:49 am

I changed my prop twice without taking the boat out of the water. Once I did it alone by backing it to a launch ramp. Then pulled it so the stern was in shallow water with the motor tilted all the way up. Stood in water about ankle deep and changed the prop.

Second time was at the dock in the marina. Turned the boat around and backed it in, tilted motor up, layed on the dock and changed prop. Boat was secured to dock so it barely moved at all.

In my mind I was making it much harder than it actually turned out to be. Even used a torque wrench to torque to spec both times. I'd have no qualms about doing it again.

You need a piece of wood (I used about a 12 inch piece of 2x4), wrench to fit the prop but, needle nose for pulling the cotter pin, and don't forget the grease!
Oh and a torque wrench if ya have one.

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bansil
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Re: Another prop question

#28 Post by bansil » Thu Aug 09, 2018 3:38 pm

That was my plan also, trim up an over dock, or we have a boat ramp at marina seldom used.

I just found out we have a family reunion Saturday, glad it is just across the field, prop will wait until Sunday.
I can't get boat in slip alone, too tight and i actually respect my neighbors boat...them tho ?

I can't wait to see if hub is also spun...something is amiss more than propped wrong, heavy pontoon that likes 10/12 at anything above 4000 rpm that doesn't add up to me

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sunedog
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Re: Another prop question

#29 Post by sunedog » Fri Aug 10, 2018 10:11 am

bansil wrote:
Tue Jul 31, 2018 1:40 am
How do i know if i need a hub kit :donno
If the prop doesn't fit, you need one.

(Sorry...couldn't resist.)

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bansil
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Re: Another prop question

#30 Post by bansil » Fri Aug 10, 2018 12:45 pm

sunedog wrote:
Fri Aug 10, 2018 10:11 am
bansil wrote:
Tue Jul 31, 2018 1:40 am
How do i know if i need a hub kit :donno
If the prop doesn't fit, you need one.

(Sorry...couldn't resist.)
:eviltaunt



:mrgreen:

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