Horsepower vs. boat load capacity help

[oxfordlawn]

My wife and I are looking into getting a new 21' pontoon boat and I have some concerns as to size motor. It comes standard with a 60 HP Mercury 4 stroke but can get an optional 90 HP 4 stroke. I went to Merc's website and found info on speed & GPH for both size motors on same size boat. But those are not real world answers I know which is why I am here.
I dont want to be underpowered again but also dont want to overpower and waste fuel. With the 60 it says I can do 14.5 burning 2.2 gph. With the 90 I can do 15 and burn 3.2 gph or 50% more. Now these tests are unloaded boats. Will I see a huge difference in speed numbers and gph's when we add a few adults and kids with coolers and stuff. Would the 90 work less hard to push a heavy boat and actually save me in fuel costs?? Sometimes I think a bigger motor will work less hard and burn less fuel. AM I correct in this thinking ? With the price of fuel and all I dont want to waste a big motor but I dont want to be underpowered with friends and kids on board.

Anyone have a 21' with a 60 or 90 here ?>? Whats your thoughts?? THANKS SO MUCH!!

[dockholiday]

Welcome

I believe your thinking is correct. Lots of different factors, especially with toons, to take into account. Toon typically plow through the water. The less horsepower the greater the plow. The larger hp will lift the front end thus cutting down on drag. The larger motor will also achieve a greater speed at less rpm, so say a 60 will push the boat to say 18 mph at 5800rpm and a 90 will push it at 22mph at 3500rpm. Had a two log toon with a 90 previously and personally that is as low in hp as I would want to go. Most dealers advertise them with 50hp and 60hp since they are trying to advertise the lowest possible price on the boat. A plus is the later model engines are getting some real good gph numbers compared to just a few years ago. My 150 seems to get as good mileage as my old 90. Not sure what the boat is rated for but I would compare the cost between a 90 and 115 and make my choice from there. Good Luck.
doc

[HandymanHerb]

Go with an E-tec and lose a lot of engine weight, with my old 50 on my 20 ft, I get 16 with 3 on it, if I can keep them toward the back so I'm not plowing.

With the 90 you should be able to run the same speed and same fuel use, but as they say go the biggest you can afford you can always slow down a big engine down.

[oxfordlawn]

Thanks for the replies
I was under the impression that the 60 would be too underpowered when we started loading up the boat. It is only $1500 to upgrade to the 90 HP fourstroke and taking into account what you guys just suggested, it would probably be best to go big so its there if needed, but can maintain a similiar speed at lower RPM's and be close to fuel usage as a 60 at the same speed. It actually makes sense-THANK YOU!

Tom

[Parasympathetic]

See how quickly he justified going for more horsepower?

I'm gonna like this guy..........

[oxfordlawn]

I want a giant HP motor that only burns 2 GPH at full throttle.\
Am I asking too much ??

[brumbyvet.1044]

Tom, What year boat are you interested in? If you are looking at a 2009 model, check out the NV logs. Sun Tracker discontinued the package on Party Barge for 2010 but these logs will double your speed with the 90. Good luck with your decision whatever you decide.

[buzzardbeak]

We have a 2185 Batata Bay from Crestliner with the 26" logs. We also questioned the 60 hp on the toon. We decided to upgrade to the 90 4 stroke and are not a bit sorry. 3 people, flat out we are getting 27.2 on the gps. With 8 people and 2 coolers, we got 24.6. We use 3500-4000 for cruise and the gph seems to be good. It is also much more relaxing just easing along and keeps our enjoyment level high, but we get across the lakes sssoooo much quicker. Our old boat was an 18 foot Godfrey with a 25 on it, so this new toon is a definite improvement.

Good luck with whatever you chose.

Frank

[WaltF]

Biggers Better!

And if you can, get Lifting Strakes!
As brumbyvet.1044 mentioned, youll go WAY faster as then the toon can get up on plane vs plowing through the water...

[wed]

Go for the 90!

I bought my 21 footer with a 60 four stroke. It performed good with two people on board. Put six adults on it and it was a dog, even with the lifting strakes. With six people the 60 couldn't even come close to getting up on the strakes.

I went back to the dealer and thank goodness he was willing to work with me. I got the 90 and it made a great difference. I can't give you gph but I am pretty sure the 90 uses less fuel than the 60 did with same load. I hear good things about the E-tek but do not have first hand knowledge. I am very pleased with the performance of my 90 four stroke Merc.

I have never heard anyone complain about too much horse power .... remember, you don't have to use it unless you need it.

[mjlyn]

Like everyone has said if you can afford the 90 go for it. I bought a used 20ft Lowe with a Merc 60 4 stroke last summer. With just me and fuel i might see 18mph with the wind. With 6-8 people on board im looking at 11mph or so wide open.

You'll never wish you had less power, but everytime i hit the water i wish i had more. We love or toon though.....spent almost every weekend on the lake last summer and had a blast. We just bought a couple 180hp Yamaha Waverunners a few weeks ago......that will cure the need for speed this summer, and the toon will be the mother ship with food, drinks and towels.

[GXPWeasel]

I agree with the rest of the guys here. Get as many ponies as you can pony up... so to speak.

I have a 90 Merc. 2 stroke on my 26' Islander, and it is enough engine, but I want more. I didn't have the choice to upgrade, as I purchased used, but I would really like to see what a 115 or even a 150 could do for me.

Oh, and your concept of " Bigger engine doesn't work as hard to go the same speed" is correct. Hell, I've been stating this for years when it comes to 4cyl vs 6cyl cars, and just now are poeple starting to listen.

Go for the 90 and enjoy brother.

[FloterBoter]

go big or stay home.

[ORAA1997]

OK I have a 115 HP Mercury Optimax and I feel like it crawls on the water. I just had it serviced and everything look good. What am I doing wrong??? SOS

[trott46]

what pitch is your prop?