Classic AquaSport

Aquasport Mechanicals - things that need a wrench, screwdriver or multimeter => Engines & engine woes => Topic started by: sturgeon on March 08, 2007, 09:38:05 PM

Title: Low Hp vs high HP
Post by: sturgeon on March 08, 2007, 09:38:05 PM

I know a lot of you guys out there want to blast around at 40 mph, but for us folks that rarely go far off shore, ie. less than 15 miles, and only then in perfect weather going a steady cruise of 20 mph is fine.  I have a 100 hp johnson that is ample power for my 19-6 and with a 17 pitch prop it jumps up on a plane.  Top speed is fine by me at 34 mph with a nice load.  

I might be moving overseas where the price of gas is double here and am considering moving down to an opti 75, tohatsu 70 or even Yamaha's high thrust 60.  One guy posted that he put an old 60 on a 170 and it did 24 mph top end.  I know lots of folks will balk at that speed, but in the old days that was a good speed since they primarily cruised at 15 or so.  

 :oops: Hopefully I won't get heckled too much for this post and if anyone has info on lower hp's on a 170 to 22-2 I would greatly appreciate it.

Title:
Post by: RickK on March 09, 2007, 05:03:41 AM

I know that my 170 won't stay on plane under about 20 mph, so I would imagine that would also be true with a 196.  A Doelfin on the motor might help keep it on plane at a little lower speed - I had one on my 110 and it still started sinking into the water at 20ish.  Good luck.

Title:
Post by: JimCt on March 09, 2007, 06:52:18 AM

75 will be fine.  Slower out of the hole, but for your mission and the cost of fuel over there should be no problem.  Correct prop will be important.

Title: Wacky
Post by: GoneFission on March 09, 2007, 05:32:48 PM

Here's a wacky idea - how about a pair of Yanmar DIESEL outboards?   :shock:

http://www.yanmar.com.au/marine/d_series/dseries.htm (http://www.yanmar.com.au/marine/d_series/dseries.htm)

The pair would only total 72 HP, but that's diesel HP - higher torque than gas - and would probably take you to 20s in MPH.  

Weight for the Yanmar is nice - each one only 130 lbs for a total of 260 - less weight where you don't need it.  
 :wink:

Think of trolling or slow cruise on a single - sipping diesel at quarts/liters an hour versus gallons per hour.  

Just an idea - worth maybe $0.02...

Title:
Post by: JimCt on March 09, 2007, 07:16:52 PM

How's prices on those diesels?

Title:
Post by: RickK on March 10, 2007, 06:45:45 AM

I had no idea they made diesel outboards  8)

Title: How about one of these?
Post by: scott_gunn on March 10, 2007, 08:31:22 AM

http://www.swordmarine.com/Products/jetpac.htm (http://www.swordmarine.com/Products/jetpac.htm)

Title: Re: How about one of these?
Post by: RickK on March 10, 2007, 09:58:54 AM

Quote from: "scott_gunn"

http://www.swordmarine.com/Products/jetpac.htm

That's cool too :!:  :!:

Title: Engines
Post by: GoneFission on April 01, 2007, 06:05:24 PM

Hey, I found out some more info on the Yanmar diesel outboards.  They are currently not EPA certified for sale in the US, but are being sold in Canada.  The weight listed (130) is kilos, not lbs, so they weigh about 270 lbs each.  The 36 hp diesel outboard is EXPENSIVE, selling for some 18,000 Canadian   :shock:  :shock:  :shock:  - I know Canadian does not = $$$, but that's still high for a 36 HP outboard.  

However, the Yanmar D36 is approved by SOLAS for use as a lifeboat engine - that definately says reliable!  It was also the engine used for a recent nonstop Sidney-San Francisco record run, averaging around 9 knots and 1.5 gallons per hour for the entire crossing.  That's crossing the Pacific on about 500 gallons of fuel!  

See ya on the water!

Title: downsizeind hp
Post by: obsessed on May 08, 2007, 11:02:32 AM

My son has a 77 19-6 we downsized from a merc 115 to a johnson 70hp. The motor moves the boat fine. We won't beat you to the fishing hole, but we save alot of fuel. We topped out at 21 on the gps with 3 onboard