Motor Confusion

[TXredfish]

Several months back I bought a 14ft aluminum V-Hull boat w/a 1960 5hp Evenrude. I saved enough $$$ to buy a new motor. This time I am looking in the 15-25hp range(Mercury) My problem is the 2 stroke & 4 stroke mix up and weight ihvoloved with the motors. I am confused and really want the 25hp 4stroke but many tell me it is too heavy for an aluminum boat. Bascially I need help in determining whcih kind of motor best suits an 14 ft Aluminum V-hull used in saltwater. And Is weight more important than hp? Is there a big difference in 2cycle & 4 cycle? Here are the manufacture's (Mercury)size and weights for the motors. Are Mercury motors reliable in saltwater?<br /><br />15hp 2 stroke- 76lbs <br />15hp 4 stroke- 112lbs <br />25hp 2 stroke- 114lbs <br />25hp 4 stroke- 175lbs

 

[steelespike]

Re: Motor Confusion

Omar, first A 4 stroke is cleaner generally <br />quieter and smoother than a 2 stroke.It will<br />be somewhat slower out of the hole and a little slower top end. In my opinion they require more maintenance than a 2 stroke both regular and repair.<br /> I think the 4 stroke 25 would make the handling poor (very tail heavy)Making it even slower out of<br />the hole.<br /> I would go with the 25 2 stroke. In my opinion even allowing for the oil mix it will cost less to run over the years and to purchase new.

 

[Mumblerone]

Re: Motor Confusion

What's the max. HP for the boat. How many people and/or load do you typically carry. The 15 HP 2-stroke might get the job done very well. It'll be leaps and bounds quicker over a 5 HP. Those 4-strokes a quite heavy for a small boat.

 

[bossee]

Re: Motor Confusion

Hi,<br /><br />Probably a 25 Hp 4-stroke will make your boat a little to heavy back there and so making it slow to plane but a light 15 hp 4-stroke maybe could be a good compromise?<br /><br />I assume you want manual start (not electric start) and no electric Trim&Tilt since without them you will save weight. But there are 25 and 15 hp 4-stroke with both electric start and electric Trim&Tilt (manual T&T is otherwise standard and electric optional). I do not know if you need Short(S)or Long(L) model (S=431 mm/17.0 inches, L= 552 mm/21.7 inches), that depend on your boat transom height, check your boat(or manual).<br /><br />About weight, compare this.<br /><br />25 hp 4-strokes:<br /><br />Honda BF 25<br />S 148 lbs (67 kg)<br />L 152 lbs (69 kg)<br /><br />Yamaha F25 (AMH)<br />S 137 lbs (62 kg)<br />L 141 lbs (64 kg)<br /><br />---------------------<br /><br />15 hp 4-strokes:<br /><br />Honda BF 15<br />S 93 lbs (42 kg)<br />L 95 lbs (43 kg)<br /><br />Yamaha F15 (AMH)<br />S 99 lbs (45 kg)<br />L 104 lbs(47 kg)<br /><br />Tohatsu 18 hp 4-stroke<br />S 114 lbs (52 kg)<br />L some lbs more<br /><br />---------------------<br /><br />Compare above against 2-stroke, for example:<br /><br />Yamaha 25 hp<br />S 106 lbs (48 kg)<br />L some lbs more<br /><br />Mercury 25 Classic<br />S 114 lbs (52 kg)<br />L some lbs more<br /><br />One of the bad thing with smaller 2-strokes (at least above examples) is they are not so "clean" to the environment. I do not think there are any small 2-stroke that has earned CARB 2006 2-star rating or CARB 2008 3-star rating, that many small 4-strokes actually has earned. For example these 4-strokes has all earned CARB 2006 2-star rating: Mercury 15, Yamaha F15 and Honda BF 15. <br /><br />Check max allowed (hp) outboard for your boat before you decide.<br /><br />You have to check above weights yourself, I do not guarantee they are correct.<br /><br />Good luck!<br />/Bo

 

[Forktail]

Re: Motor Confusion

It looks like you're really wanting a Merc. Are they reliable in saltwater? Certainly. But in my opinion it makes little sense to put a 175 pound Big Foot 25 hp on a 14' alum boat, 4-stroke or not (heck, a 40 hp Tohatsu is only 158 lbs!) And it makes little sense to put a 15 hp 4-stroke that weighs 112 lbs when you can put a 25 2-stroke on that weighs only 2 pounds more. I love 4-strokes for sure, but Merc really sets the 2's and 4's apart in weight with their smaller outboards.<br /><br />In my opinion it's between the 15 hp 2-stroke at 76 lbs, or the 25 2-stroke at 114. I don't think you'll be happy with the 15. So my vote is the 25 hp 2-stroke. <br /><br />I'd certainly take a look at Yamaha's 2-cylinder 2-stroke 25. It's 106 lbs and made specifically for your scenario.