What size engine for 17'8" deep v Fast fisher opinions of Evinrude 70 and 115?

[10mpg]

I have a Fletcher Cruisette 178 it looks like this..


(google image)

It needs an engine, I have a choice of two, a crossflow 115 V4 Evinride and a VRO 70 3cyl Evinrude, both have PTT and controls both are in my (quite tiny) budget of £800/$1350

The boat will be used on coatal family fun trips and the odd fishing trip further out, i would like some decent speed but i don't need to win any races, fuel economy is a serious issue, because my funds for playing are limited..

My thinking is that the boat is rated for a 50 to 150 engine, but the 115 I've heard is a gas guzzler and the 70 may not have enough poke to keep it planing when I'm 5 people up with gear and equipment and might not tow a ring very well..

I'm looking for opinions really i'm new to boating so just looking for info..

I'm thinking something like a Yam 90 3cyl would be a perfect compromise but they are twice my budget so out of the question..

Help please!

 

[eavega]

Welcome to iBoats!

So, I understand your concern about fuel economy, but I sincerely believe the 70 HP will leave your boat very under-powered. If the hull is rated for up to 150 HP, the rule of thumb is you need approximately 70% of max rated HP to plane your boat reliably. 70 HP does not make it there. I had a 70 HP Jonson on the back of a 15' tri-hull, and can tell you that while the 70 was able to get the boat on plane with 3 adults or 2 adults and 2 kids, there was just not much left over for any towing of tubes or anything of that sort. Despite the higher consumption of gas, you will probably be happier in the long run with the 115 HP. Also, I'm not even sure you would be at that much of a disadvantage fuel-consumption wise with the 115. The 70 will probably have to strain a lot and even if you do get the hull on plane, you are talking about running it an near WOT most of the time. The 115 will give you a better throttle range, where when paired with an appropriate prop, you may be able to have a cruising RPM in the ~3000 RPM range which will be better on fuel than having to run at constant WOT.
Again for comparison, I ran that 70 HP on the 15' tri-hull and would burn about a gallon an hour. My boat now is an inline 4 cylinder I/O (135 HP) and that burns roughly about the same. Difference is that the 70 would run constantly at 5500 RPM, whereas the 4 cylinder I/O is run at about 3000 RPM to achieve the same results in speed.

Rgds

Eric

 

[southkogs]

I'm a BIG fan of the 3cyl Johnson/Evinrude outboards, but I think Eric's right: You'll be way underpowered with a 70HP. I have a straight six I/O, and I'm actually surprised how efficient it is. Uses more gas than my old 65 HP did, but not as bad as I thought. I'd go with the 115 and deal with the "guzzle."

 

[Frank Acampora]

Oh, Man! That is a beautiful hull.

As with the others, the 70 is a really efficient three cylinder engine but it is still only a 70. While it may plane the hull, I don't think it will give any decent performance. The 115 may use a bit more gasoline but no one says you must cruise at wide open throttle all day. And, you may find that "loafing " the 115 at cruise will actually use less fuel than working the 70 harder.

Besides, the V4 is an engine that has been around since Ole Evinrude was a cub scout and is almost bullet-proof. It started out as the "fat fifty."

Not only that, but these engines went up to (if I remember correctly) 130 or 140 so there is the possibility of squeezing a little more out of it at a later date.. Since you intend boating coastal waters, the extra power of the 115 makes sense. Weather can be unpredictable and sometimes you just need to run for shore. At that time a couple of MPH more, while not a lot, may just make the difference between getting home calmly and a white-knuckle ride.

While fuel money may be tight--it is for all of us (filling my 30 gallon tank, about 120 liters, now costs me well over 100 U.S. bucks PLUS oil costs) Compared to other amusements for the family a day on the boat can be quite reasonable.

 

[Streffpilot]

Go big or go home. So I agree that the 115 is the motor to use. Just remember, that just because you have 115 horses available doesn't mean that you HAVE to use all 115. Although I do usually use all of my available ponies. Using less than WOT can save some gas.

 

[10mpg]

Thanks for all the advice so far! Great forum..

I've been relably informed via a scan of the orgional sales brochure that my boat is only rated from 60-115 so it would be on it's limit with the big 'rude though everyone here seems to agree with you goys on the choice..

Just food for thought from perspective especially for Frank your $100 tank to fill over here would cost around $280 at current currency exchange rates using regular gas/petrol withough allowing for oil, so I'm hoping you can see why I'm fretting about fuel consumption...

Not for the first time I'm wishing i lived in a country with a few more lakes and a few less taxes (our fuel cost is 72% tax)...

 

[southkogs]

... Not for the first time I'm wishing i lived in a country with a few more lakes and a few less taxes ...

Me too