upgrading power

mic4fish · 03-23-2006, 04:49 PM

I have a 179 sea runner and am geting serious about upgrading my big motor, it has a 50 horse now, I'm looking at a 90 4-stroke mercury, any pros or cons on this motor is it going to be enough power? is it to heavy for my boat? My 50 hr is also a 4-stoke I love it its just not enough power especialy if I have a couple of big fellas :depressed:

Catching Nemo · 03-23-2006, 06:19 PM

You should have a sticker, by the helm, which states max weight and max horsepower for your boat.

However, I think your boat is rated up to a 115hp. If so, I would skip the 90 and get the 115 for the following reasons.

1. You are going to add 150 pounds (+ / - depending on how heavy your 50 is) by moving up to a 90 Merc.

2. With a 115, you gain 65 horses versus 40 and still only increase weight by 150 pounds.

3. You might burn less fuel, for a similar cruising speed, because of fewer rpm's on the bigger motor.

4. If you go with a 115 hp, and it is the rated max for your boat, you won't/can't torture yourself with anymore "what if's" :grin:.

5. Finally, you are only talking about approx. $800 more for the 115.

You would probably be happy with the 90 but I can't see any real reason not to go for a 115. Plus, the boat will have better resale with a higher horse engine.

D-tangle · 03-23-2006, 06:24 PM

I'm with Nemo. The bigger motor won't wear out as quickly and I always fear being under-powered in a pinch, also. Bigger, baby!

mic4fish · 03-23-2006, 09:06 PM

I was told from a guy at stevens that a 75 2-stroke optimax would be ideal for my boat less weight and the same low end tourqe as a 90. He seemed to think that my boat would realy get up and scoot with the optimax I guess that is the other side of the coin.
thanks

Catching Nemo · 03-23-2006, 09:24 PM

Nothing wrong with going with a 2 stroke.

However, unless I am reading it wrong, the 75 Optimax weighs only 11 pounds less than the 4 stroke 90 Merc (375 vs 386) (The E-TEC 90, however, weighs 320 pounds). I don't see any weight advantage between the Mercs. I do agree that the low end torque will be similar but the engine will also be working harder.

Draggin' Bait · 03-23-2006, 09:27 PM

I have the 115 Yamaha 4-stroke on a 17 foot Arima. Incredible engine, but in retrospect I could have been as happy with the 90. It IS nice to have the security of the extra power, and in the Y line the weight difference between 90 and 115 is only about 30 pounds (one of the reasons we went with the 115). However, as great as the fuel economy is I believe I'd have gained 1/2 to 1 mpg more with the 90, with only about a 4 mph loss in top speed (36 vs. 40). Since I virtually never go WOT, that would have been a minor issue. If you go to the Yamaha website they have numerous engine/boat tests published. You should be able to find something similar to your hull with some numbers to review, which should give you some ideas as to what to expect in the speed/economy areas. I don't think you'd be dissappointed with either 90 or 115, but I suspect 75 would not give you what you expect. Happy shopping! Larry

SOL · 03-23-2006, 10:24 PM

I have the same exact boat. Have a 115 Honda hanging off the back, great hole shot and you can expect top end right at 38mph fully loaded.

The Honda weighs in at 505lbs, so yes it adds some weight to the rear and brings the bow up a little bit, but I've found that it rides better in the bigger swells. However, when trolling it seems to blow around more in the wind. Less boat in the water...

SOL · 03-23-2006, 10:25 PM

Oh, and your boat is rated to 125hp

Starfish · 03-24-2006, 06:32 AM

Quote:

Oh, and your boat is rated to 125hp

I'd definitely recommend going for the 115hp if you can swing it. The 90 would be adequate... the 115 would be great. Whenever possible I like to go as close as possible to the max for the hull. At intermediate speeds your economy won't be much different, and you'll have more power when you need it.

El-Kabong · 03-24-2006, 12:53 PM

Draggin bait, got a deal for you.

I'll trade you my honda 90 for you yami 115. I have a 19' sea chaser and wish I had a little extra motor...

OR

mic4fish, I'll make you a deal on a Honda 90. Great motor, still under warranty...

EK

Draggin' Bait · 03-24-2006, 01:17 PM

Very generous offer, Kabong, but at this point it's pretty much of a done deal! I know the Hondas are great engines, but we've really fallen in love with our two Yamahas (115 and 8). I'm serious though, that a 90Hp four-stroke would have been plenty of power on a 17-Arima. I expect I'd have been quite happy with the Honda also, but as mentioned above, the Honda weighs much more. Also, when we were in the market Yamaha was offering an extended three years warranty (six years total), at no extra cost.

El-Kabong · 03-24-2006, 01:29 PM

Just trying to help you out. It just breaks my heart to hear about a fellow Arima Owner/ifisher being burdened with too much motor.

In case you reconsider, I am talking trade plus cash!

mic4fish · 03-24-2006, 07:02 PM

Thanks everyone for the good info

Yes sol my boat is rated up to a 125 ultimately I would love to go with a 125, I do believe that you cannot have enough power but like it was when I first bought my boat budget dictates what you do its unfortunate. The problem is Im finding some good deals on 90s and not 115s or 125s :depressed:. Kabong I think you are right I would not be happy with a 75 and yes I might be interested in you 90 e-mail me if you are serious.