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New 4 stroke - boat rides stern heavy


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Hello all.  Question for those of you that have repowered with 4 strokes. I have a 96 Maverick MA, 18.5 ft.  Came with a 175 Johnson 2 stroke. Just repowered with yam 150 sho. The motor is about 100 lbs heavier. Boat sits and runs stern heavy. Totally changed the way the boat rides. The thing I loved about the MA is the ride. 
 

what have you all done to help this?  Dealer put a 19P 3 blade. Asked him to let me try an 18P 4 blade for more stern lift. 
 

motor was pricey and is awesome. Just kinda down on the ride at the moment. 
 

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Noooooooo. 😔 This was not what I was hoping to hear. But the battery moving forward helps. Moved mine while back and its noticeable. I am no jack plate expert but thats going to set the engine back further and may lend towards more squat perhaps.

On my 2 stroke 19 was not enough prop and currently running Yamaha 21M and thats a crazy good one for 2 stroke 150s on our hull. Is it slow to get out of the hole? 

 I did for a while (when boat double as ski and wake board duty) run a 4 blade Power Tech PTC4R18PCL200 that was a stern lifting beast for the hull but slows her down. I would say call Ken at Prop Gods in Ft Myers and Marcus at PT as both are darn handy with help.

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I know mercury props do not get much love around MBG owners but I’m going to throw this out there. The mercury Enertia is a 3 blade prop that runs excellent on butt heavy applications. It lifts well and is fast too. It can be used with vent holes to help with hole shot but I doubt you would need that. Look around for an Enertia not the Enertia eco. You can usually find them new a bit cheaper than some of the more pricey props. 

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Thanks for the replies. Yes. With the 19P it has great hole shot. While breaking the engine in, the first hour, I didn’t go over 1900rpms. The second hour, kept below 4000, with most of the running around 3100rpms. After the second hour, Yamaha says to run normal. So I opened her up. Ran up to 5000rpms, then wide open. It hit 5600rpms, lightly trimmed with a top speed of 48mph.  Speed is not hugely important. Stern lift is very important right now. So, giving up a few mph on top end is no big deal. 
 

shop is ordering a 4 blade now. Might stick with a 19P 4 blade. And try to dial it in. I’m sure it will be fine. But, these new 4 strokes are so heavy. I know evinrude is going out of business. In hindsight, I would have preferred something lighter for sure. 

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7 minutes ago, LittleChief said:

I would get rid of the jackplate. That much weight further back doesn't help the issue you're having.

Father of 4 - does your boat have trim tabs?    I would agree with Little Chief, even though I'm actually planning on adding a jackplate to mine.   I still (hopefully) have enough life in my 2 stroke and I run some areas with submerged logs.   From a performance perspective, there is no value to the jackplate for the MA that I've ever seen, only the value of an "insurance policy" for your lower unit in skinny, rocky, questionable water.    You'll lose 50 pounds or more just by removing the plate and pump, and probably the equivalent of another 50 to 100 by moving that engine closer to the stern.   

I completely made up those numbers, but we've got to have some engineers on here who could calculate what 6" of set back with 400 pounds equates to.

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Hmmmm.  Interesting.  Never considered removing the jackplate.  I do use it, although not much.  We fish FL panhandle, and no "true" skinny flats.  And yes, I do have trim tabs.  I had never used them before, as there was no need to.  But, I will be using the boat this weekend, and will use them.  See how that helps.  

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34 minutes ago, Fatherof4 said:

And yes, I do have trim tabs.  I had never used them before, as there was no need to. 

have you called Marcus @ Powertech props?  He will provide you with a recommendation on a prop.  Listen to him.

Also, with the JP, you will definately need to use tabs to help even out and eliminate porposing.  

With a heavy 4 stroke and JP and battery in the stern,  it will be squatting.....

If you take off the JP it will most likely change quiet a few things....

Send pics of your set up.

DC

 

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I havent called Marcus, but ,I do have somewhat of a relationship with Ken at PropGods, and I have reached out to him.  Will try to post pics, but, I *** at most things..."technology"..

 

As far as removing the jack plate... "changing quiet a few things.."  - any ideas or specifics?  Like I said, I rarely use the jack plate, but, like knowing I have it. 

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Fatherof4 , I also repowered my 93 MA with Yam150 six years ago. Yes it is 100 lbs heavier than the 175 two stroke I also took off. I’m Running 19” 3 blade for hole shots, and yes you give up top end. Mine tops out at 42mph. Never had a jack plate, but I do have to use a little tab to keep from porpoising.  I’m also in panhandle area- Carrabelle

Good luck

 

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Greenbone - Thanks for the reply.  Yours sitting really stern heavy?  I did run the Yamaha 19P prop on Sunday.  I was pleased with the prop, topped out at around 48 mph.  At 5600 rpms.  Mine is a Yam 150SHO if that makes any difference, as I have no idea.  Will run tabs this weekend, and see how it does.

Yeah, we fish St Joe Bay quite a bit and will be there this weekend.

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Moving batteries to the console is a good start, but i wouldn't remove the jackplate.  Do all your weight shifting and then find the right prop for the setup.  Propping is very important and can make or break the way a boat handles, planes out and rides.  As HoneyB said... Merc Enertia is really good 3 blade that offers impressive lift while still carrying the nose. 5 degree wedges can also help with low speed porpoising     

 

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Father of 4 - 

It seems like you have two related but different issues.   

1) Your boat now SITS stern heavy, which will impact draft and make the stern more susceptible to overwash.   

2) Your boat now rides stern heavy, causing it to porpoise, ride bow high, reducing the effectiveness of the hull design.

It may help to clarify which issue you are addressing and which solution applies to which problem.   Some solutions will fix both, some will fix one or the other.

Regarding issue #2, with my first MA (1987 ) I didn't have trim tabs, never needed them, and never had any porpoising.    When I got my 2000 MA, I was surprised that the boat had a tendency to porpoise at the mid range of the throttle - this issue would get more or less noticeable based on load, fuel, use of livewells, and passenger arrangement.   However, I always need a little down tab to run between 1/3 and 2/3 throttle.   That may just be my boat/prop combination.

A prop will help #2, but obviously won't affect #1.  Removing the jackplate will help both, but primarily #1.   Moving the battery to the console will help both, probably equally.   

Not sure if breaking the two issues apart helps, but it may help you prioritize solutions that fix both problems

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That Yam 150 is at least the same weight or perhaps heavier than the old 175.  But the MA's don't need a jack plate and they run very well without them, the CG with that jack plate changes the boat's static position and it'll struggle to give you the ride these boats are renowned for.  If you can move weight forward that'll help, but.... if possible remove that jack plate and run the boat on some different props and see what you see?  Good luck!

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Thanks for the Reply Dave, when doing research, it showed that the new Yam 150 is indeed about 100lbs heavier, hence it sitting stern heavy.  I am very interested in removing the jack plate.  Dont want to rush it, as we are heading into fall.  Might tackle this project over the winter.  Will keep everyone posted.

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  • 2 months later...

Well, took the boat to the shop this morning to remove the hydraulic jack plate.  Seems this will help a few issues I have...Hoping for the best...I do have a 17P 4 blade and it did really well, although it did run a little higher rpm for the speed.  Considering switching to a 19P 4 blade.  Will try one out and go from there.

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Thanks for keeping it updated as I follow this one for sure! Did you try a 21? I would say if you know someone with a M-21 Yamaha Pro Series 14.5 X 21 it may be worth a shot. Our hulls like those 4 blades for the lift it seems but that 21 has performed the best for me.  I ran a 4 blade Power Tech PTC4R18PCL200 for years when the kids were skiing and wake boarding and I had to put my MA into bay boat mode. It its slower, diff engine than your fresh power but it would jump up under big load and stick tight in turns.

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