choice of outboard

rudders_midship · #1 02-18-2003, 10:25 PM

Almost time to buy an outboard my local Evinrude / Johnson dealer recomends a 115 hp on my 20 sceptre that is what came originly on it back in 1978, since he has taken care of the boat for all those years. It has had a 150 on it and he says it was too much motor on such a light boat plus you can't use the speed most of the time at least here in the northeast on a river with 8 knots of currentand chop alot of the time not to mention the gulf of maine hardly ever flat he says it would do 40knots or so with the 115 he also doesnt recomend the four stroke he says its a dog and the 115 will eat it upcomments welcome pics soon.

SEAFARI · #2 02-18-2003, 10:49 PM

Rudders- You will see 35-38 mph with a 115.
Most will run a 130-150 on the 20' hulls.
with gas prices @ $2.25-2.75 gal. this summer
I would look at the 140 Johnson 4-Stroke. You
would get 42-45 mph and great MPG.

Chris

Finster · #3 02-18-2003, 10:52 PM

Can't go wrong with a 115, though if the 140 was out when I bought mine I'd probibly bought that. 40 mph not kts sounds about right. No complaints with mine, I love it.

John R · #4 02-18-2003, 10:54 PM

I don't think a 115 will do 45 MPH. The 140 Suzuki on a light 202 Scout barely does 45. Based on what I have seen and read here, a 140-150 would be the ideal motor on these. The 115 was the standard engine on these and many are happy with it. Cost/speed/use - but don't expect 40 knots with a 115. The article on this site about the Seafari from 1969 showed the 140 I/O just shy of 40 MPH not knots...

Good luck and waiting for some pics - how much snow did you get?

[ February 18, 2003, 09:55 PM: Message edited by: John R ]

Jon G · #5 02-18-2003, 11:10 PM

Rudders my 74'CC has a newer 115 with a stainless prop. It will do 30 Knts. Trimmed up and flat out. Not a bad size engine for this boat just don't expect a speed demon. It will cruies in three to four footers all day. The price is right for the smaller engines too theres a huge differance between a 115 and a 175(my choice if price were no object and gas was free [img]images/icons/smile.gif[/img] ) The water aroung here does not allow for to many 40 Mph days anyway so its no loss for me. I don't think that a 150 would be too much though probably just right.

Reel Smoker · #6 02-18-2003, 11:16 PM

Evinrude has a promotion until April 4 to 7.00$ per horsepower or what has me thinking they extend the warranty from 3 years to 7.Something to think about.Does anyone now the cost on a new 250 Yamaha 4 stroke? RS.

Finster · #7 02-18-2003, 11:20 PM

Just for reference [img]images/icons/rolleyes.gif[/img] 1mph=1.2Kts. So 40kts is 48mph. Go with the 140. [img]images/icons/grin.gif[/img]

ScottM · #8 02-19-2003, 10:23 AM

Reel Smoker, Yamaha doesn't have a 4-stroke 250 yet, they do have the HPDI 250 though. Perhaps you're thinking of the new Suzuki 250 4-stroke?

Finster, your math is correct but your conversion is backwards - 1 knot = 1.15 mph [img]images/icons/wink.gif[/img] .

Finster · #9 02-19-2003, 11:02 AM

quit splitt'n hairs. ever try to do a quick conversion using 1.15? [img]images/icons/rolleyes.gif[/img]

John R · #10 02-19-2003, 11:10 AM

Actually mile per hour times pie devided by nautical miles to the root of statute miles divided by 9700...

Finsless - I think he meant 1.2mph = 1 KNOT instead of 1mph = 1.2Kts. like you wrote - but you already new that didn't you. [img]images/icons/tongue.gif[/img] [img]images/icons/grin.gif[/img]

While we're on near useless formulas (or is it formulai [img]images/icons/shocked.gif[/img] ), did you know that for measuring stripers you can use (length x girth x girth) divided by 800 (L*G*G/800=weight) to get a very close approximation of weight? Not sure what other fish that formula works for...