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Motor performance?

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Motor performance?
I have a 1993 Yamaha 60hp on my 19'3" Honker.... it will do just over 30 MPH. What performance improvements do you think I would see with going to a 1998 75 hp?


https://stlouis.craigslist.org/...ller/6263979679.html

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***Phil (Chesapeake Boy) Nowack***

http://www.mapleridgetaxidermy.com
http://www.philnowackphotography.com

Nothing like the north wind pushing snow at your back, a bird in your hand, and chessie with ice on his coat at your side.

Birds brought to you courtesy of Nikon, Benelli, and Kodi
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Re: Motor performance? In reply to
maybe putting a fin on it
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Re: Motor performance? In reply to
Are they both oil injected, or 4 stl?





Don't just do something, Stand there!
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Re: Motor performance? In reply to
I noticed that at least in my merc 4 stroke, the main difference was that the 75 was much heavier. and more expensive.





Don't just do something, Stand there!
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Re: Motor performance? In reply to
Phil,
Just a guess but I think the only real difference you will see is an increase in ability to push a heavier load. You may see a slight speed increase depending on how well your present prop is matched to the load. This would require you to experiment and match a prop to the new motor/hull/load package. The 75 will most likely be able to get on plane sooner than the 60 hp.
I had a 700cc 4 cylinder motorcycle which I traded in on an 1100cc 2 cylinder motorcycle. The 700 was a faster bike, both off the line and top end. However the 1100 carries a heavier load without losing performance. I would expect you would get similar results with the 60 to 75 engine swap you are looking at.

Take care, Huntindave McCann Smile SHELL ROCK IA “As sailors grow older, the wiser ones move to smaller boats.” —Thomas Firth Jones, Multihull Voyaging
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Re: Motor performance? In reply to
Without a doubt it would handle the load better. The 60 puts her up on playing adequately quick. Several sources think I get maybe seven mph more out of it which I be happy with and I think I would migrate my 60 down to my Skype. I just don't know if it's worth it. The 75 is the same powerhead as the 90 is I don't know if that helps me at all or not.

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***Phil (Chesapeake Boy) Nowack***

http://www.mapleridgetaxidermy.com
http://www.philnowackphotography.com

Nothing like the north wind pushing snow at your back, a bird in your hand, and chessie with ice on his coat at your side.

Birds brought to you courtesy of Nikon, Benelli, and Kodi
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Re: Motor performance? In reply to
Phil,

Compare the block weights.

If the 75 is the block format for 75-100hp you won't see much. If it's the top end for 50-75hp range you'll see more. Maximize hp to engine weight should max engine efficiency.

Not certain if era/technology will have much impact. As mentioned you will likely haul a heavier load better just for having more hp geared.

Just had this conversation with a dealer re: 100hp vs 115hp. For $2k more there isn't $2k increase in performance as the 115hp is the same block for the range to 150. I was thinking he said Yamaha, but saw on their website they do a lot of Honda. Regardless, the shared-block over a range of hp seems industry standard, just not certain what years have different cut offs
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When things are good in my life, ducks fly in my dreams. When things are bad, they don't.
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Re: Motor performance? In reply to
I have a 60... The 60-70 have a common block... The 75-90 have a common block

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***Phil (Chesapeake Boy) Nowack***

http://www.mapleridgetaxidermy.com
http://www.philnowackphotography.com

Nothing like the north wind pushing snow at your back, a bird in your hand, and chessie with ice on his coat at your side.

Birds brought to you courtesy of Nikon, Benelli, and Kodi
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Re: Motor performance? In reply to
Have you checked in to whether that 60 can be bumped up to 70 if they share common block. should be a lot cheaper than new motor?
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Re: Motor performance? In reply to
i went from a 2 stroke 50 hp at 26 mph to a 75 hp etec and gained a 9 mph. 50 hp was a 2 cylinder the 75 is a three. And yes the etec much newer.
Located in South Jersey
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Re: Motor performance? In reply to
Good Morning Phil,
Getting the correct prop on the 75hp or even the 60 will make a big difference in performance, depending on what you want. if its more speed, 4 to 7 on the top end with a 15hp increase, if its a hole shot you want a slightly smaller prop on either motor would do the trick ( you will lose a bit of top end) be careful not to over rev. ultimately you won't gain much for the money, if you go 30 for and hour or 38 for an hour the difference is only 8 minutes. as noted in another reply the biggest advantage would be getting on plain with a heavier load. good luck
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Re: Motor performance? In reply to
Performance aside, I see little upside going from a 24 year old motor to a 19 year old motor. $3750 is a lot of money to drop on such an old machine. Find a 2010 or newer. JMO
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Re: Motor performance? In reply to
I found another 1998 for $1000 less. I hear you on the age, but how boat motors are actually USED, or used up. Finding a tiller, of any make over 60HP is Very difficult. If I could get up tp 38mph, or 35mph loaded.... It might be worth it. I bout by '93 in '06 for $2000... I still see '93s that they are asking $2500+ for.

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***Phil (Chesapeake Boy) Nowack***

http://www.mapleridgetaxidermy.com
http://www.philnowackphotography.com

Nothing like the north wind pushing snow at your back, a bird in your hand, and chessie with ice on his coat at your side.

Birds brought to you courtesy of Nikon, Benelli, and Kodi
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Re: Motor performance? In reply to
Phil,

I am not sure how far the run you need to make is.

For me, just get it up on plane and glide.. In my old tub, that was about 16 mph.

I guess you could go faster if you want or need to.


Maybe I am a minimalist.

I'd rather have room for another dog than a bigger power plant.


Lots of folks out there don't take care of their motors. They use them during the summer and put them away wet after being ridden hard.

Might be worth the time to take any prospective motor to the mechanic to have them check the seals etc.




Anya Always says, "the best days of your life are when you get the boat, and then when you finally sell it"





Don't just do something, Stand there!
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Re: Motor performance? In reply to
My current power plant is fine... I just like speed!

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***Phil (Chesapeake Boy) Nowack***

http://www.mapleridgetaxidermy.com
http://www.philnowackphotography.com

Nothing like the north wind pushing snow at your back, a bird in your hand, and chessie with ice on his coat at your side.

Birds brought to you courtesy of Nikon, Benelli, and Kodi
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Re: Motor performance? In reply to
If your running aluminum prop try a stainless. That should improve performance.

Tom
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Re: Motor performance? In reply to
Would look into changing prop pitch before moving up hp. You might find gains and better response just in pitch of prop alone. Now you also may change you cavitation potential by doing this. Had a 40 hp Tohatsu with 12 pitch prop and on a 18' Grumman Roughneck. When fully loaded would get near 21, (3 guys and decoys). Unloaded it would do near 27. After about 7 season I switched up to a 13 pitch prop, now the boat still did roughly have an increase in speed fully loaded by 1 mph but empty it would get almost exact same speed empty. The bad part was also it took longer to get up on plane. I always keep two props in my boat just in-case and when switching I accidently purchased a 13 and 11. I put the 11 on there just to test. The speed for fully loaded actually increased to 24 fully loaded and an empty increased to 29 empty. The first major difference was the hole shot of the 11 was far better than the 12 and 13 fully loaded. It also gave me better response with speed due to being in the sweet spot of RPM range. I would first look into your motors RPM range and try to match the pitch to the range to give better hole shot and cruising speed. You will get a better speed by increased Hp but you also increase your gallons per hour and increase the weight mounted on your boat. Which may have you pursue a larger tank increasing weight, heavier motor and finding yourself in a not much greater condition you were in before purchasing a larger Hp motor. Plus the cost of a few props can be less than a couple of hundred dollars versus 1000s. An having an extra prop though it might not perform to your liking gives you the advantage of just in case moments to get you back to the truck. I know at the time an aluminum prop on the 40 ran around $65 to $120 depending on brand. Have not looked but I bet a 60 hp is not much more if not near the same. Of course stainless is has always been around triple the price. Spend your time and money on the props first. You may be surprised.
Regards,
Kristan
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Re: Motor performance? In reply to
I have a properly pitched Ss prop

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***Phil (Chesapeake Boy) Nowack***

http://www.mapleridgetaxidermy.com
http://www.philnowackphotography.com

Nothing like the north wind pushing snow at your back, a bird in your hand, and chessie with ice on his coat at your side.

Birds brought to you courtesy of Nikon, Benelli, and Kodi
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Re: Motor performance? In reply to
That Stainless will give you more efficiency and umph in your throttle up.

I ran Aluminum on the duckbomber, because it was more forgiving to strikes and sudden impacts.



It is a heck of a lot easier to bend the prop back if it is an aluminum prop. Cheaper too.

We didn't have much bedrock, but plowed a fair amount of sandy shoals.



Believe me, there were days that we bent it back.

plenty.



The strength of a stainless prop is a double edged sword.

You can get right up and go.


For sure you will have less prop flex and more push up and out.

But if your lower unit is comprised of aluminum and potmetal...

t is like putting a titanium joint on a dog .


Sure, the dog 's leg wont give you any issues, the joints are just as light as can be, and strong too.


Sometimes the prop gave its very life for us, in leu of losing the entire lower unit.




Maybe for us, running the aluminum prop was a kin to having a circuit breaker in the power train.


If hamer a rock with stainless under power, it is going to be something you will never forget. Financially, and perhaps from the standpoint of safety.


If you bash into one with an aluminum prop, you might be able to limp it on home and throw on a new prop (without destrouyng your lower unit.)





Don't just do something, Stand there!

Last edited by:

todd tennyson: Aug 21, 2017, 9:22 AM
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Re: Motor performance? In reply to
I will never run alum. Flex too much, in efficient, etc... With rubber hubs, I am bit worried about my lower unit. It if it going to be wrecked, the alum prop will not help.

Bedrock gobble any prop... Lol... A spare is always a good thing to have !!! And hope you never have to use it!

I just want more speed without sacrificing torque/quick planning.... The other problem is that I am cheap.... So... I don't want to buy new.

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***Phil (Chesapeake Boy) Nowack***

http://www.mapleridgetaxidermy.com
http://www.philnowackphotography.com

Nothing like the north wind pushing snow at your back, a bird in your hand, and chessie with ice on his coat at your side.

Birds brought to you courtesy of Nikon, Benelli, and Kodi