Repowering

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jpmathers
Posts: 19
Joined: Thu Sep 13, 2018 5:39 am

Repowering

#1 Post by jpmathers » Thu Feb 21, 2019 12:27 pm

I am getting ready to get a bigger mercury for my 21'4 lowe, its 2015 with strakes and under skinning. Planning on cruising , fishing and maybe pull grandkids on tube.
I am looking at all 4 strokes,
2015 75 hp with 1 year left on warranty $6300
2014 115 hp no warranty left $6500
2018 60 hpCT 2.5 yrs left on warranty $6000
2012 115hp no warranty left $6100, these are all about 8 hour drive , found a local 1hr drive 2012 60 hp bigfoot( apprx 97hrs) for $5300.
I am new to pontooning and cant really find much on this boat and different speed and motors, I am keeping my mercury 9.9 for a kicker in local limit lakes. I would like to be able to get at least 20mph out of it, just looking for opinions , all motors are within 1k in price but some have warranty left on them.

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Marc K
Posts: 742
Joined: Fri Jun 01, 2018 4:35 am
Location: Eustace, TX

Re: Repowering

#2 Post by Marc K » Thu Feb 21, 2019 5:15 pm

Just a couple of quick thoughts:

Remember that warranties are only as good as who is standing behind it. I would be asking for the hours on each motor that you are considering. Depending upon brand, you can often get a download of hours and percentage of hours at various throttle settings.

Since you have a 20 MPH target in mind, do some more digging to see what HP on YOUR boat will get you there. I happen to agree with you about 20 MPH being a decent speed for towing kids on a tube and general cruising - but many (most?) people here feel that is too slow. More motor will get you more speed and a good cruising speed at a lower RPM. Also remember the balance on your boat. From my perspective, 115 HP would scoot you along quite well and get you past 20 MPH, but I suspect that 75 HP might get you close.

Remember that propping your new motor will require some effort because of the many factors including how high/low the motor is mounted. I am brand new at this also. Hopefully, some of the experts will chime in and add/subtract/correct my comments!

Welcome!

Marc
Big and ugly but we love our 1999/2000 Crest II DL with a Yamaha F115

r&s20
Posts: 146
Joined: Sun Dec 08, 2013 7:37 am
Location: toledo bend loisiana

Re: Repowering

#3 Post by r&s20 » Thu Feb 21, 2019 5:36 pm

i would think you would want to look at either of the 115hp.

on a regular toon the 75hp would get you close to the 20mph you want, but with the lifting strakes i don't think it will be enough to get the boat up and will cause extra drag ( due strakes be submersed) you will have to overcome to get to 20mph.

i have a 115 on my 20 foot toon with lifting strakes and it works well for me, i had a 90 hp on it and it had to work had to get on the strakes

with 115 i can cruise at 22mph easy, best top end was 29mph, all gps speeds
if it ain't broke-it ain't ours
94 smokercraft 20ft 90hp johnson
fish and cruise
I am not ADULT SUPERVISION !

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ROLAND
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Re: Repowering

#4 Post by ROLAND » Fri Feb 22, 2019 3:07 am

JP... I happen to own a 20 foot boat with a yamaha 75 horse 4 stroke on the back. It is sufficient to pull a tube with kids on the back. I can tell you that under perfect lake conditions, smooth water / no waves, my boat will run around 23 mph - that's tops at wide open throttle. And thats not when pulling a tube. 23 mph is not fast, but it's fast enough for our needs.. If you're going to be taking 8 to 10 people out at a time, you might want to bump it up to the 115.. I can tell you my son has a 115 on his boat and it is not that much faster than mine, however his boat is a little larger, 22 footer. As someone else mentioned, before you make a decision on which motor, see if you can find out how many hours are on each.. good luck with your decision.
Roland & Jo
2010 Bennington 20 Sfi
Yamaha 75 4 Stroke
Shreveport, Louisiana

boocat
Posts: 269
Joined: Sun Aug 28, 2016 8:09 am
Location: Texas Hill Country

Re: Repowering

#5 Post by boocat » Fri Feb 22, 2019 4:10 am

agree, you won't be "cruising" 20 with a 60hp.

jpmathers
Posts: 19
Joined: Thu Sep 13, 2018 5:39 am

Re: Repowering

#6 Post by jpmathers » Fri Feb 22, 2019 4:27 am

One of my other concerns was riding bow high with the weight of 115(apprx 360) plus the 9.9 kicker(apprx 80) lbs. The motors are from a marine that rents out about 30 boats and replaces motors every 2/3 years.

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TWB
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Joined: Sun Mar 18, 2018 7:40 am
Location: Navarre, FL

Re: Repowering

#7 Post by TWB » Fri Feb 22, 2019 6:29 am

Hey, JP.
I have a 75 Merc on my 24' Landau. No strakes, no underskinning. I usually can ease along at about 18 gps. That's often with 4-6 people and all the other needs - coolers, junk, etc.. I agree with the others who feel that a 115 should certainly be enough to keep you around 20-couple mph with some to spare.

Pulling mostly younger kids, I find 17-18 mph to be adequate for us because we are on the intracoastal with some light chop most of the time. Makes it fun bouncing over the waves, rather than the thrill of flying along.

:2cents
Paul & Michele
2003 Landau DX 24' Cruise "Loretta Jane"
2003 Mercury 75hp
My Rebuild: http://pontoonforums.com/viewtopic.php?f=16&t=26135

"Don't waste brain cells over something you can do nothing about." --My Wife

riplipper
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Location: St Augustine, Florida

Re: Repowering

#8 Post by riplipper » Fri Feb 22, 2019 7:15 am

115 and you will be very happy. It will let you cruise at a nice speed without having to run at 5k rpms all the time.
I am the guy at the boat ramp that gives you dirty looks when you are a complete idiot and too stupid to know it.

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