Whaler Central - Boston Whaler Boat Information and Photos

Posted by Gitnjiggy on 12/15/13 - 9:34 AM

I recently purchased a 2003 170. The prior owner blew up the factory installed Merc 90. So I got the hull and a 2013 new trailer at a steal. I am only interested in Yamaha or Suzuki Motors. I am more of a Yam fan as I have twin F150s on my Grady and have owed 2 prior Yams with no issues.

The hull plate says it can handle 410 lbs. The new Yam F115 is 401 lbs. Obviously, the F90 works, but I am interested in more power and better cruise speed with less RPMs.

Any suggestions especially from someone with the F115 on the 170 hull. Boat will be used in Sound and ICW. Fishing, Skiing, etc. Will always have a load on board as I have 3 girls with friends. Is the F115 overkill?

Posted by Finnegan on 12/15/13 - 11:21 PM

I think you have the right idea, and if I had a 170, I would definitely want the 115 HP on it. The boat can easily handle it, and I've always thought it was intentionally underrated by Whaler at only 90 HP.

I don't have time to hunt down the links, but if you look around Google you should be able to find at least three articles on 115HP repowers of the 170.

One that comes to mind involves the same engine you are talking about, but in Mercury form. From 2002-2006 Mercury was using the Yamaha F115 EFI powerhead for their own 115 four strokes, (often refered to a "Mercahas") and a fellow put one of those Mercs on his 170. He really loved the setup.

Two others that come to mind involve the Mercury Optimax 115 ProXS, a 375# 123 HP engine, and another repower with an Evinrude E-tec 115 HO (an engine now taken out of productionfor emission issues, I believe).

Most of these boats would run pretty close to 50 MPH I believe, and all performed very well.

I think you would be very happy with an F115 on the boat.

Posted by rwethereyet on 12/16/13 - 6:51 AM

Will there be kids or friends using this boat on their own at some point.....? Do you want or need that much power in those type of situations....? I like more power myself, but when kids become part of the equation....?

Posted by Phil T on 12/16/13 - 7:31 AM

Larry (Finnegan) is thinking of "Barney" on CW. He was one of the first to upgrade to a Mercury 115 soon after purchasing his 2003 170 Montauk. I recall the weight increase was negligible.

{in reviewing threads, Marsh and Dogfish also re-powered with Mercury 115. Barney subsequently repowered again to a Yamaha F90}

As to the Yamaha F115, as a former owner let me share a few observations. It is a great motor but a bit heavy. Maintenance is straightforward except for the vapor separator tank (VST).

The VST on this motor is mounted behind the air intake manifold. Annual service to this includes draining, replacing the filter. Removal of the VST requires removal of the high pressure fuel rail and the intake. It's a 25 minute disassembly if you have done it before. I considered it a PITA and is a downside to this motor. If you have a yard service your engine, you are looking at least an hour. ($125).

Given the cost of the engine harness, binnacle, gauges, new instrument panel, etc I would recommend you stay with Mercury. You are looking at $1k in rigging to move to Yamaha.

Edited by Phil T on 12/16/13 - 9:09 AM

Posted by Finnegan on 12/16/13 - 1:09 PM

Phil - the person I was referring to with the 2003 "Mercaha" 115 EFI repower Ray Beaugrand , with a 170 named "Tabasco". I believe he has since sold the boat. During those years, the Mercury 90 and 115, with Yamaha powerheads, weighed the same @ 388#.

Posted by Gitnjiggy on 12/16/13 - 5:25 PM

Thanx I read the info from Tabasco and concurred with his opinions. I was aware Yam made early 4 Stroke Mercs. I will spend the $$ on the new controls to ensure I have new/complete "system" and know what I have as I prefer to avoid anything to do with a black motor. I had 75 on a 1996 Dauntless 15 and had a bunch of issues. My buddy had twin Verado 275s...same thing. I doubt I will turn my girls loose solo with the boat maybe the wife who drives my 27 Grady with no issues.

Thanx for the responses. I will decide and pull the trigger this Spring.

Posted by BSG on 12/18/13 - 7:42 AM

I just went from an old 115 Johnson V4 to a new direct inject carb 3 star Nissan and the 90 is plenty of power. The 115 was a good runner, and maybe a couple miles per hour faster like 45 tops, than the new 90 at about 41 or 42. The old engine was rated at the power head and the new one is rated at the prop so maybe only about a 15 hp difference. The new engine is 35 pounds more, and I can tell as the older hull has a harder time with the big heavy engines but not bad. There is guy on here that just put a 140hp on his old Montauk so I guess you can do just about anything. I just don't see the need for more than about 100hp in this type of boat. All in all I think if you are not into big thrills the ideal hp for the older Montauk would be about 70hp in the form of the new Yamaha. Your hull is the newer design and is a bit wider. Let us know how it all turns out.

Posted by Ridge Runner on 12/20/13 - 7:18 AM

I have repowered two 170's with 115HP motors - a 2003 with a Mercury Opti 115 ProXS and a 2005 with the E-Tec 115HO. I believe a 115HP outboard is a nice set-up for this boat. I have had no issues insuring the boat/motor combination. There are very detailed post on CW about my repowers.

Posted by Gitnjiggy on 02/08/14 - 5:53 AM

#10

Stop the press! I was getting ready to pull the trigger on the current F115 and Yam has come through with the B variant. This will be the perfect match for the 170. Off to Miami boat show next weekend to check it out.

http://www.yamahaoutboards.com/yamaha-advantage/news/company-news/yamaha%E2%80%99s-new-f115-more-compact-and-powerful