Motor size question?

[fishingguy]

Got back into open water fishing a couple years ago, after several years away from it. In the past I've never had a big enough boat to matter. All were 14' or 16' with 15hp to 25hp motors. Now I own an older alumacraft competitor with a 70hp. Will be up grading in a year or 2, and want to understand what I'm getting into. I've read motor size should be no less than 70% of the hp rating. My question is why? What instances is the bigger motor needed? Better?

My current boat does around 32mph and I don't see much advantage of going 40mph. On a 10 miles run 10mph faster gets me there 2 to 3 minutes sooner. Some one please give me the ins and outs of bigger is better!

Oh ya, my eventual up grade will be to a 16.5' to 17'sc navigator, fish hawk, or pro v, ect.... Thinking of a 60hp to 90hp 4 stroke. If that helps with your answers. Thanks for any help!

[drippinwet]

I'm no expert, but the way I understand it is like this. The proper operation of an outboard motor depends on its' prop rotating at a certain RPM which is usually attained when the boat gets up on plane. Think of how your legs work when you are riding a bike. If you were to attempt to haul people on the back of it and do hills while in high gear, your legs would soon wear out. This is what will happen to your motor as well. I would assume the recommendations are based on the weight of the boat and it takes into account the MAXIMUM load capacity. I would stick to as close to the max as possible, but checking with a dealer is not bad either. It really is based on type of boat and how much weight you will be adding (fishing gear, water weight in live well, spare parts and tools) and prop pitch. Honestly stick to the 70% rule.

[BPBOB]

There are a number of reasons to "go big" IMHO

1.If you ever have the boat loaded with friends/family you will appreciate the extra push of more horsepower.

2. If you ever do any tubing or other watersports,you'll appreciate the extra HP

3.The boat will perform better to get you around without you pushing the higher RPM's

4. Resale is better down the road with closer to maxed out HP

5. You will never find someone who's upset they bought too much horsepower,but the converse is true.

Finally, you don't have to push it to the top end if you don't want to ,but you'll appreciate it if you need it to get in off the lake some day.

Good luck!

[BobT]

I had a Lund Rebel 16 that was rated for up to 45hp. At the time I bought the boat new I couldn't afford to include a new outboard so I outfitted it with a used 25hp, which is slightly more than 50% of the boat's rating. It worked just fine....as long as I was alone or only had one other rider. If I had three adults in the boat it struggled to plane out but that wasn't the worst part.

One time I was out on Osakis with two other guys and as the day progressed the wind alos picked up. Before long we were in some pretty hefty waves and that poor 25hp was no match for the high water. It actually had a hard time controlling the boat while moving against the wind. A year or two later I was planning a family trip to Lake of the Woods and decided I didn't want to risk getting caught on that lake with high waves so I upgraded to a 40hp. That was the best decision I ever made while I owned that boat!

Part of the reason for having the right size outboard is safety.

[SkunkedAgain]

I'll provide the counter arguments. First of all, I don't see how putting strain on a motor will make it fail sooner. If that were truly the case, every 4-cylinder car would be shot after 100k miles because 3-4 people rode in it occasionally.

As far as wanting more power, it's a personal thing. If you feel like you might take people fishing with you or go tubing then you'll likely never regret a bigger motor. If that's not the type of boating you do then don't worry about it. Despite the step-down tricks and other claims, big motors can not troll down to the same speeds that a smaller motor can. As far as fuel consumption, some will say that you spend less money on fuel because you aren't running as close to WOT. However, I doubt that the fuel costs will match the added cost in going up 20hp on a motor unless you own it for life.

As for resale value, that does play into it sometimes but again it depends on who is buying. You will have a smaller potential buying market but that doesn't mean that you can't sell the boat. It will be appropriately discounted for the investment that you did not make in a bigger motor. There are plenty of folks that primarily fish by themselves and enjoy the space of a slightly bigger boat (livewell, storage, etc.) but don't need to cruise at 35mph to get there. The size of the lakes that you fish also makes a difference. If you're fishing small to medium size lakes primarily, why strap on a big motor? Just so you can sell it for more in 15 years?

I must qualify all this by saying that I maxed out the motor on my most recent purchase, but that's because I regularly do take four people and gear across Vermilion. When I'm not doing that, my preference is to be in my 12' Starcraft with my 5.5hp motor.

[pulleye16]

It really depends on what body of water you fish on. If you fish small lakes then yeah, speed is no issue. If you're hitting up larger lakes, then speed is very important.

I,feel 30-40 mph is plenty for any boat on any lake in MN. If your future boat can do that with 60hp then IMO I'd say its fine!

[fishfearme]

BobT hit it right on! Its not really about speed or performance, it is about safety!

[solbes]

I think planing should be a much bigger consideration than top speed. I agree that 32 vs 40 vs 48 mph doesn't make a huge difference to me. Although faster is always better, right? It would be more of a concern if I fished bigger water where I made longer runs to my honey holes. Typically I get from one end ouf our lake to the other in just 3-4 minutes, so no big deal. Leech is a little different.

What I can't understand is spending $12-20k for a new boat hull and then saving $2-3k to get a motor that might struggle to plane out. You are paying for a lot of Hull design and engineering that only works as designed with higher horsepower (75% of max). It can be frustrating to be in one of these boats. The problem is usually compounded when when adding people and loading it down. I want a boat to plane out in a hurry. Dropping the bow in a just a few seconds vs 10-15 is more fun and safer IMO.

[BobT]

I used my Rebel with the 40hp for a few years and then sold it to get into my current boat, which is a Sylvan Advnturer 1600 with a 90hp. I did this not for the speed but because my wife wanted me to. The Sylvan has a lot more room and depth adding comfort, storage, and safety that she wanted and at the time the price was right.

Anyway, with both of these boats I rarely use them at full throttle for a couple reasons. First, maybe I'm a bit of a pansy, but it can be a bit frightening, especially if I'm by myself. Second, once I get up over about 3/4 throttle, the fuel gauge seems to be affected somehow. Besides, I'm never in that much hurry that I can't take it a bit slower and enjoy the view on a nice boat ride, which is also part of the experience.

[marine_man]

I think a lot of it is fully understanding your boating application...

If you know you only fish lakes where wind / waves weather conditions aren't a concern because of size / shape / whatever, and you know you're only going to be fishing with two people and a light load, and you know you're not going to be doing any tubing / skiing / water sports then trying to follow the 75% rule of thumb probably doesn't make sense.

I think where the 75% rule fits is when you get a boat, and on a off year you head to Mille Lacs with a buddy because you've got a new boat... and you catch a bunch and go back the next time with three guys instead of two because the fishing was so good.. and the wind comes up. Now you've got the extra person, his gear and weight and you're fighting the wind to boot.

That 75% rule of thumb pays off in my opinion for the "unplanned" things more than the planned ones.

marine_man

[fishingguy]

Thanks for all the replies! Makes a bit more sense to me than before. More, to a point is better, just in case you need it!

Thinking a 4 stroke when I bite the bullet. Any thoughts on size of a 4 stroke, versus same size 2 stroke? Weight versus, hp? Ect... thanks again!

[gregg52]

Real MEN run..E-TECS !!!!

Way lighter!1

And power to spare !!!!

[delcecchi]

Not sure what power range you are talking about

ETEC 130 or 115 390 lb

Suzuki 140 410 lb

115 416 lb

Merc Opti 150 431 lb

Opti 115 375 lb

EFI 4ST 399 lb

Looks very similar to me.

[gregg52]

Well they sure are deceiving !! looks wise

not arrow and sleak!!!!!!!!!!!!!

[fishfearme]

So you are saying the Suzuki 115 weighs more than the 140? That makes zero sence.

Not sure what power range you are talking about

ETEC 130 or 115 390 lb

Suzuki 140 410 lb

115 416 lb

Merc Opti 150 431 lb

Opti 115 375 lb

EFI 4ST 399 lb

Looks very similar to me.

[walleye365]

BOBT iv got the same boat its 2004 with a 25hp fourstroke i run about 28mph from what my gps says i know its not spot on. How much more speed did the 40hp do for you. Im thinkin to up grade myself Thanks

[BobT]

I actually never clocked it with the 40hp. All I know is that when I was alone there wasn't much of the boat on the water at full throttle. I even had to add spacers under the top motor bolts to tilt it under more because the boat would porpoise even with the motor all the way down. Mine was a tiller so I suppose the weight was distributed too unevenly toward the rear. After I added the spacers I had much better control.

I really liked that boat. Mine was a 2001 model and after I had it for 10 years I had it outfitted the way I liked. Splash guards, bow mount, electronics, I added interior lighting, compass, etc. My wife wanted a bigger boat so I was "forced" into trading up.

[marine_man]

So you are saying the Suzuki 115 weighs more than the 140? That makes zero sence.

Del's just the messenger...

Suzuki's specs are exactly as delcecchi has them posted... here's side by side comparison:

marine_man

[walleye365]

I looked after my post and mine is rated for max 40HP so will see thanks for the info.

[drippinwet]

First small cars rarely do last past 100k miles and if they do you are putting a lot of money and time into an engine that is not worth it. Second, you're comparing apples to oranges because an outboard motor is nothing like a car engine. The specs are their for a reason. You wouldn't see an F-350 with a 4 cylinder motor, why, because it will burn itself out trying to move that massive amount of weight. Same theory applies with the motor and boat. You cannot put a 15 HP motor on a pontoon without having the motor wear out much more quickly than say a 75 HP. Not to mention MPG you would get from not having an undersized motor working so hard to keep up.

[FBMH]

Like someone else said, take into mind the body of water. Is it large or smaller? In most cases, a 90hp motor will do the trick for you. it will go fast and be able to hold a large number of people in the boat or if youre trying to get to a spot across the lake in a short time just before the eyes start biting!

[FBMH]

First small cars rarely do last past 100k miles and if they do you are putting a lot of money and time into an engine that is not worth it.

are you kidding me? My moms kia spectra that is almost 8yrs old has 150k miles on it and it runs like a champ. Not sure what youre trying to get at

[drippinwet]

are you kidding me? My moms kia spectra that is almost 8yrs old has 150k miles on it and it runs like a champ. Not sure what youre trying to get at

And she is not towing around trailers and not having a lot of stress put on the motor. Add extra weight to that and tow something around and see how long it lasts. If all you do is drive from point A to point B with not a lot of gear and no tubers, then go with a smaller motor. But if you will load up on gear and pull tubers around then go bigger. Its common sense here, the more weight you add the more stress put on motors, especially smaller ones which are working twice as hard.