90 or 115 ETEC for 18SF?

[pjzabo]

OK, I thought I found a mint 2003 Yamaha 130 to put on my 18SF, but it turned out that motor had issues. I think I am going to bite the bullet and pay up for a new (leftover) ETEC. My transom was redone, but the PO didn't raise it so needless to say, I want to stay as light as possible.

Question - will the Etec 90 do the job for this boat, or do I want a 115? I would not go 130 because I don't want a motor that is too stressed - looking at Evinrude's website the 90 runs 69 hp/liter, the 115 is 67 hp/liter but the 130 is 75 hp/liter. My gut is that the 115 is the right motor, but if I can save 70 lbs and possibly $2K I would consider the 90.

Thoughts? 90% of my use is short fishing trips on the LI Sound, 2 people on the boat usually (which means 470 lbs since I'm big and so are most of my fishing buddies). I'll go out in 1-3' seas, but usually stay home if 3-4+' is in the forecast.

Thanks -

Pete

[McGillicuddy]

To bad on the 130 Yammy... $2G will buy a lot of gas at 5 mpg. I doubt you'd be running wot cross the sound all that often, and even so 115 probably gets you only 3 or 4 mph more.

I think that lightweight 90 would be sweet on the 18. Probably get 35mph wot and barely get to know the guys at the filling station. drier feet, too if you have thru-hull scupper setup

Either one is a winner...

[Snookerd]

90 hp etec? It will be fine if that is what your leaning toward. 115 would be better, of course. Cost is the issue for many of us. 65Bowrider has a 115 on their 19 bowrider and their is no complaint for weight. Weight is not the issue on the 2 motors. The issue is power and how resale would affect an underpowered boat.

[Snookerd]

The issue is power and how resale would affect an underpowered boat.

Forget resale, it's an old boat with a new motor. We just witnessed a great deal on a 23 with newer 4 stroke power sell for cheap, it's a tough market for sellers(no hard feelings sellers )Great points on the 90hp scenario. You can't go wrong either way........

[eggsuckindog]

115 and don't look back - perfect I had one, 90 won't cut it, they are almost as big as a 20 -

[pjzabo]

Thanks everyone for the opinions. I am going to investigate the price difference on the 90 vs. 115 (it needs to be at least $2k in my mind). I may also have a shot at getting a used 90 since they've been out longer than the 115. One last thing - power and weight notwithstanding, the 115 must be a smoother motor V4 vs. inline 3.

[Fr. Frank]

The 115 Etec is 390 lbs, just 15 lbs more than the 75-90-115 Optimax. (a bit less than the old 20" V6 Mercury's at 396 lbs.)

In contrast, the 90 hp Etec is just 335 lbs. If you've got a reliable Tohatsu/Nissan dealer nearby, the commercial HPDI 90 hp Tohatsu is only 315 lbs, the 115 is 390 lbs, same as the Etec.

Yamaha no longer sells 2 stroke HPDI midrange motors in the USA. (Still available in Canada, Mexico, and the Bahamas, though) The F90 is 369 lbs, the F115 is 414 lbs.

The Yamaha HPDI 90 (as sold in the Bahamas) is listed as 317 lbs, the HPDI V4 115 at 367 lbs.

[Bushwacker]

HP/liter is an excellent way to assess how durable or "high strung" an engine will be. When I bought my Seafari back in 1975, there were no V-6's; choice was between a 115 and 135 V-4 (same 100 cu. in. powerhead, just carb and exhaust tuning differences.) After one old time mechanic, who used to provide motors to the local commercial kingfish fleet, told me that a 115 would outlast "about FIVE 135's!", I went with the 115 and never regretted it. Speed difference was supposedly about 3 mph, which I considered a small gain for big loss in durability!

A lot has changed in 35 years however, and all of the E-Tec's appear to be very durable, so either the 90 or 115 would be fine. If you're running in a rough chop, I'd vote for the lighter motor because boat will plane at a lower speed with it and ride better, and it'll still push the boat faster than you can comfortably run anyway! Just make sure you prop it so it turns max revs with max load. Might also consider a 4B prop. The extra blade provides more stern lift and the additional blade area will provide a great hole shot if you get the right dia./pitch combo.

[Fr. Frank]

As a SeaCraft dealer in the early 80's, I rigged a lot of 20' SF hulls with either an 85 hp or 115 hp V4 motor. The 115 was the most common power choice. However, the 115 had a 10% top speed advantage of about 3-4 mph over the 85, and used about 10% more fuel across the spectrum. Most people think that because a 115 is laboring less at a cruise of 25 mph, and therefore should use less fuel. We never found that to be the case.

According to Carl Moesly, the "design motor" for the 20' SeaCraft hull was a single 110 hp Mercury "Tower of Power" inline 6 cylinder motor, which actually produced between 88 and 90 hp at the prop shaft on average. A pre-1976 Mercury or Evinrude 135 hp motor averaged 114-115 hp at the propshaft.

With the exception of Tohatsu/Nissan, all current production 2-stroke 90 hp rated motors produce an average of 103-105 hp at the propshaft. The Tohatsu/Nissan averages 81 kw or 108 hp. However, service on T/N motors can be hard to find.

Even though they weigh the same 375 lbs, and had a cost difference of only $350, I elected to go with a 90 hp Optimax over a 115, largely because of my experience with rigging these hulls with 85 hp and 115 hp motors 25 years ago. I knew the 90 hp was adequate to the task. I am quite satisfied with that choice. (especially the 5+ mpg at cruise)