posted 01-18-2004 11:01 AM ET (US)            

It would be helpful if you could clarify which engine you are asking about:

--classic 2-stroke
--Optimax 2-stroke
--4-stroke

posted 01-18-2004 11:52 AM ET (US)            

You should not consider this engine as "basically a Yamaha" with a black paint job. The power head of the 115-HP Mercury engine is a Yamaha design. The rest of the engine is a Mercury design. Yamaha also sells a 115-HP 4-stroke, but other than the power head it is quite different from a Mercury.

The Mercury variant of this engine uses EFI. Previously the Yamaha engine used carburetor induction. I think Yamaha finally upgraded their model in 2004 to use EFI, too.

The Mercury engine is about 20 lbs. lighter.

The Mercury engine uses a Mercury lower unit and can use the full line of Mercury propellers. The Yamaha engine uses their lower unit and propellers, although adapters are available to use Mercury propellers, too.

The Mercury engine uses Mercury remote controls and gauges. It also uses the Mercury power trim and tilt system. The Yamaha engine uses their own remote controls and gauges. Some of the Yamaha gauges are quite nice, although they are also rather expensive. The Yamaha engine uses their power trim and tilt system.

The Mercury engine comes pre-rigged, installed, and supported in the U.S.A. by a very large dealer network with excellent parts distribution.

The topic of who the actual manufacturer of the power head is has been discussed before. It seems that there have been sightings of Yamaha-brand 115-HP engines with the power head painted black, the Mercury color. I think I recall mention of Mercury brand engines with the blue paint job normally seen on the Yamaha engines, too. I don't know if the precise location (Japan or Wisconsin) where the power heads are made has been determined. It may be that each makes their own, one makes them for both, or both make them and interchange them as necessary.

Mercury and Yamaha have a long history of joint venture production of outboards, and this 115-HP 4-stroke is just another example. A number of other engines in the current Yamaha and Mercury lines are made jointly or made by one and shared with the other partner.

I don't know of any particular problems associated with these engines, either the Mercury or the Yamaha. I certainly would not pay thousands of dollars more just to replace one brand with the other.

In general, I think all the comments I have heard about the 115-HP 4-stroke Mercury have been very positive.

posted 01-18-2004 12:10 PM ET (US)            

Mercury/Yamaha 75-115 4-strokes
http://continuouswave.com/ubb/Forum4/HTML/001110.html

Who Makes Which Motor?
http://continuouswave.com/ubb/Forum4/HTML/001527.html

Yamaha History
http://continuouswave.com/ubb/Forum4/HTML/001354.html

(Boy--for a guy who owns two older Yamaha engines I sound a little biased in that article!)

posted 01-19-2004 08:35 AM ET (US)            

"Previously the Yamaha engine used carburetor induction. I think Yamaha finally upgraded their model in 2004 to use EFI, too."

The Yamaha 115 four stroke, since its release, has always had electronic fuel injection. The Yamaha 90 four stroke on down have carburetors. From what I understand, Yamaha is soon to release electronically fuel injection for the smaller four strokes soon.

posted 01-24-2004 09:28 PM ET (US)            

See:

http://continuouswave.com/ubb/Forum4/HTML/001503.html
http://continuouswave.com/ubb/Forum4/HTML/001581.html
http://continuouswave.com/ubb/Forum4/HTML/002053.html
http://continuouswave.com/ubb/Forum3/HTML/004814.html

posted 01-27-2004 11:41 AM ET (US)            

I purchased a 2003 Dauntless 16 with the 115 Merc 4s with a s/s prop. It's a terrific motor and the boat performs admirably while sipping fuel at all speeds. She'll reach 45 MPH with a light load downhill. She also trolls well at 1.5 to 2 mph. I put about 30 hours on her this past summer with no oil consumption and no maintainence required.

There was only one issue. In the first 5 hours, the linkage became very tough to shift and I had a hard time finding neutral. It would slide past neutral into the opposite gear, which is, naturally, unacceptable. I returned it to the dealer, who, with little resistance, conceded that the lower units were problematic and Merc would replace the lower unit at no cost. It was completed this week. I won't have an opportunity to water test it until Easter in Hilton Head.

It has been documented that the stainless steel propeller, due to it's increased weight and momenteum at the time of shifting, causes the clutch to clunk into gear. It's not as bad if you reduce throttle to idle, go to nuetral for a full 2 seconds then into gear with authority. I am considering a composite prop to ease this tendency.

Also be sure that the motor is propped to produce a full 6000 rpms with a light or medium load.

posted 10-15-2010 10:31 PM ET (US)            

1. The rear cover on the baitwell would rattle like hell each time I'd push up the throttle.

2. The locks in the cowling came loose and just fell apart.

3. The rubber stopper where the cables would go into the engine would always pop out.

4. You would never know if the throttle was in neutral for sure. One time I almost pulled my wife off the dock thinking that the engine was not in gear. Had it checked and the dealer said nothing was wrong with it!

posted 11-18-2010 02:47 PM ET (US)            

Sheikofthesea

posted 12-03-2010 04:10 PM ET (US)            

I am closing the thread. Too much confusion here. Even in c.2004 there were three different models of Mercury 115. Now in 2010 we have a totally different motor, the Mercury 115 VERADITO FOURSTROKE. Let's keep the comments separate. If owners of the Mercury 115 VERADITO FOURSTROKE want to brag about their motor, just start a new thread on that topic. Don't join this six year old discussion about a different motor.