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Author Topic:   Mercury 115 Concerns
alanfujii posted 01-18-2004 01:43 AM ET (US)   Profile for alanfujii   Send Email to alanfujii  
I'll ask the question anyway even though it appears I don't have much of a choice. I ask the dealer whether I can put another make of outboard on the Dauntless 160 rather than the Mercury 115. I was told that it would costs thousands of dollars difference since they would have to take all the wiring setup for the Mercury and rewire it for the different outboard. Since they really do not have an immediate use for the outboard the best they could do is hold it for me and wait to sell it to a person needing to re-power. The dealer then assured me that the Mercury engine is basically a Yamaha with the exception of the lower unit and the black cowling. Plus it has a 5-year warranty. I do not see a lot of complaining on this forum concerning the Mercury outboards. Am I to take it that my fears are unfounded? How has the Mercury 115 been from a maintenance standpoint? I do find it extremely irritating that I cannot get the outboard of my choice when buying a boat.
tabasco posted 01-18-2004 07:18 AM ET (US)     Profile for tabasco  Send Email to tabasco     
Are you talking about a 2 stroke or 4 stroke?
jimh posted 01-18-2004 11:01 AM ET (US)     Profile for jimh  Send Email to jimh     
The boat you mention, the Boston Whaler 160 DAUNTLESS, is sold with three different engines of 115-HP rating.

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

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

Debate about the mandatory tie-in sales of Mercury outboards with Boston Whaler boats is an old topic, a horse beaten to death.

Peter posted 01-18-2004 11:36 AM ET (US)     Profile for Peter  Send Email to Peter     
He must be referring to the 4-stroke based on dealer assurances relative to Yamaha.
jimh posted 01-18-2004 11:52 AM ET (US)     Profile for jimh  Send Email to jimh     
From your mention of the dealer's comment about being a Yamaha engine under a black cowling, I make the inference you are talking about the 4-stroke 115-HP Mercury outboard.

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.

The type of service and satisfaction you will get from either of these engines probably depends more on how you use and care for them, and also on the service and support of the particular dealer in your location.

jimh posted 01-18-2004 12:10 PM ET (US)     Profile for jimh  Send Email to jimh     
Good previous discussion on this topic:

Mercury/Yamaha 75-115 4-strokes

Who Makes Which Motor?

Yamaha History

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

Mercury/Yamaha 4 stroke OB Joint Venture

alanfujii posted 01-18-2004 11:08 PM ET (US)     Profile for alanfujii  Send Email to alanfujii     
Yes, It's the 115 four stroke.
Judging from the replies, I'm gathering that the comfidence level of the quality and workmanship of the Mecury 115 is high and that I should have no concerns.
lhg posted 01-18-2004 11:42 PM ET (US)     Profile for lhg    
Alan - what would be the "outboard of your choice", as you mentioned above?
alanfujii posted 01-19-2004 02:13 AM ET (US)     Profile for alanfujii  Send Email to alanfujii     
My first preference would be Honda 4 stroke but since their 115 weighs too much then the Yamaha 115-4.
millerbr posted 01-19-2004 07:45 AM ET (US)     Profile for millerbr  Send Email to millerbr     
I have the Merc 115 4-stroke on my Dauntless 160 and am very happy with it.
Clark Roberts posted 01-19-2004 08:32 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
I am very happy with my 2002 Merc 115 EFI four stroke pushing a 1979 Revenge 21 mounted on a Bob's Machine 6" set-back power jack plate and swinging a 15" Stilletto SS prop at 5800 rpm at wide open throttle (WOT) and approx 38mph. Performance is perfect for my very long distance cruising and fuel mileage is about 5.5mpg overall. I bought this engine because of the warranty extension incentive (total of 5 years) and have been very satisfied and now have a little over 450 hrs of trouble free useage. BUT, there is no valve adjustment at all and any valve problems will require a new head assembly (with twin cams and four valves per cyl) so down the road what expenses do we four stroker owners have in store? Above information was relayed to me by my local Merc mechanic (whom I have known for over 30 years). I assume that all the Yamaha/Merc 4s engines have the same "no adjustment" valve features. Comments please as I haven't looked at tech manual for myself... but plan to do so.
PMUCCIOLO posted 01-19-2004 08:35 AM ET (US)     Profile for PMUCCIOLO  Send Email to PMUCCIOLO     

"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.

lhg posted 01-19-2004 01:37 PM ET (US)     Profile for lhg    
Alan, you're in luck then, as the Merc is a Yamaha powerhead, only lighter because it does not have to carry around the increased drag and weight of the V-6 gearcase that the Yamaha uses. You should be happy with it, and I'll bet it's a better engine than the automotive based Honda 115, being a full 119 pounds lighter. This makes me wonder why you put the Honda as first on your list.

Clark, with respect to valve adjustments, valve jobs, etc., I'm wondering if this an issue at all on four stroke outboards? It seems with autos, you never hear of anybody needing a valve job, or valve adjustments anymore, esp[ecially on the 24 and 32 valve high tech engines like a GM Northstar. That is something I haven't heard in years, since unleaded gas and valve rotators came into being.
What have you heard on this service issue regarding outboards?

Clark Roberts posted 01-19-2004 05:48 PM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Larry, I'm not really worried about lack of valve adjustment per se. In automotive use the engines get lots of use, maybe daily, and in all seasons. Some outboards are not used regularly and some are put up for the winter and therefore can suffer valve seat/valve corrosion during these periods of no use. The engines that are used regularly will have smooth, shiny valves and seats due to the rotators...etc... My 115 EFI 4S will not suffer from little use but there must be lots of the 4s engines that are seldom used or layed up for several months... Am I a worry wart or what!? Discussion???? Happy Whalin'... Clark... Spruce Creek Navy
Kid Stuff posted 01-24-2004 07:29 PM ET (US)     Profile for Kid Stuff  Send Email to Kid Stuff     
there have been a number of issues with yam 100 and 115 4 stroke power heads regarding the engines "making oil" and water entering the crank case via poor oil pump seals that are now being redesigned. If you go on The Hull Truth and do a search for "making oil" you will find the threads. Merc and yam use the same power head and now some Mercs are showing problems in this regard. Some do not show up until 150 or more hours put some show up much earlier. I have personally seen two boats at my marina with 115 yam 4 stroke come in with the crank case loaded with diluted oil.
jimh posted 01-24-2004 09:28 PM ET (US)     Profile for jimh  Send Email to jimh     
You will find several articles here on ContinuousWave regarding 4-stroke engines of all kinds "making oil." This problem seems to come up in a number of different models and makes of 4-stroke engines.


I don't think it is particularly endemic to the Yamaha/Mercury power head on the 115-HP engine.

ocuyler posted 01-27-2004 11:41 AM ET (US)     Profile for ocuyler  Send Email to ocuyler     

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.

I highly reccommend this motor on the 160 and you will too after hauling ass around with it for awhile.

kglinz posted 01-27-2004 09:00 PM ET (US)     Profile for kglinz  Send Email to kglinz     


The Yamaha engines have a valve clearance adjustment. The smaller engines have Rocker Arms with adjusting screws and the larger engines adjust using shims. This info comes from the Yamaha online parts catalog. I do have the Merc/Yamaha maintance manual and the explains the procedure for changing shims. I don't think much adjustment will be required if you run good clean oil. Check the Mercury Parts Express for your engine and see if there's a listing for shims. On the Yamaha 115 there are 53 different shims. They call them "Pads". If you'll give me your engine S/N I'll check as well.

DAVID GRAY posted 10-14-2010 12:32 PM ET (US)     Profile for DAVID GRAY  Send Email to DAVID GRAY     
I have a 2004 115 Mercury FOURSTROKE Saltwater-series with the Yamaha powerhead. I have had no problems [until] today. With a water pump change it was realized the exhaust tube that mounts to the powerhead was corroded off and fell right out. It has been spraying water around the inside corroding everthing. The oil pan and exhaust tube and probably more have to be replaced. I have never not trusted this motor. And it was caught in time before it corroded through the oil pan. But when you take somthing this far apart it may never be the same. I do run in saltwater and it has never sat one night without being flushed. And I live on a lake so it sees a lot of freshwater too. Mercury sells a saltwater series--it should have lasted more than five years. The problem is Yamaha has the powerhead and Mercury is supplying the lower end and using from what I saw a cheap piece of metal for exhaust flow. Has anyone heard of this? My dealership has never seen this. I called mercury and of course they said they haven't. Could I have the only lemon out here?
sosmerc posted 10-15-2010 11:47 AM ET (US)     Profile for sosmerc  Send Email to sosmerc     
The corrosion "issue" is well known, especially around Yamaha service centers that deal with salt water customers.
I deal strictly with Mercs and have not yet encountered that specific problem, but I am sure it will only be a matter of time before some of my "Yamaha powerhead" Mercury 90 and 115 customers have the problem too.
Ferdinando posted 10-15-2010 10:31 PM ET (US)     Profile for Ferdinando  Send Email to Ferdinando     
I purchased a 2008 190 Montauk with the Mercury FOURSTROKE 115. I could not wait to get rid of that engine. Mind you nothing big did break down but I had these small quirks from day 1.

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!

I sold the engine after 8 months and bought a new E-TEC. The rattle of the baitwell is gone. I know excatly when it's in neutral. Have not had "any" issues from day one since I switched engines. Will never ever go back to a Merc, and If I buy another new Whaler it will be with the engine of my choice, not theirs.

nemored posted 10-21-2010 08:16 AM ET (US)     Profile for nemored  Send Email to nemored     
I did the same on my 2007 Montauk 190. That Mercury 115 was a pain (lots of reasons). I put on a Honda 90 (no its not under powered). I would not buy a new whaler with that engine again.
Jefecinco posted 10-21-2010 08:30 PM ET (US)     Profile for Jefecinco  Send Email to Jefecinco     
[CHanged Subject]
Graumann posted 10-25-2010 12:01 AM ET (US)     Profile for Graumann  Send Email to Graumann     
I bought my 190 Montauk in August, 2008. It was a left over 2007 model. I have the 115 HP Mercury FOURSTROKE with almost 200 hours on it. This is one sweet and reliable motor: plenty of power with up to six in the boat, plenty of speed up to 40 (gps)with just me and a full tank, and excellent mileage. Hard to believe the negatives being posted about this motor. Maybe the positives aren't posting.
sheikofthesea posted 11-18-2010 02:47 PM ET (US)     Profile for sheikofthesea  Send Email to sheikofthesea     
Wow your baitwell rattles and the rubber cable organizer pops out, Egads!
I have had the Merc 115 for four years powering my 190 Montauk. WHat I treasure about it is its reliability ( I go on long 8o mile trips), it always starts up, it purrs ( when the baitwell starts buzzing I put a cloth in the hatch), and winterizing is a dream, Yes there is something cool about the E-tec but I am getting a lot of mixed messages about its reliability.
Be sure that you are clear about what is covered under the warranty. I banged the prop and thought they would fix it but since i did the damage to it they wouldn't cover it.


Ferdinando posted 11-27-2010 09:00 PM ET (US)     Profile for Ferdinando  Send Email to Ferdinando     
Well Sheik I don't have one complaint about the E-Tec, not one. Running on 1 year of use and it has not missed a beat. The only thing I miss about the Merc was the excellent fuel mileage but thats it. Would not trade the get up and go nor the little quirks for better fuel mileage.
sapple posted 12-02-2010 09:54 AM ET (US)     Profile for sapple  Send Email to sapple     
I have the Mercury 90 EFI fourstroke that came with my 170 Montauk purchased new in 2008 (left over from 2007). I now have about 400-hours. My understanding is that the 75, 90, and 115 of this engine are esentially the same engine but set up differently for the different models. Overall, I have been very satisfied with this engine. It starts instantly every time. Great power and fuel economy. Very clean and quiet. No breakdowns or performance problems so far.

I had the same minor problem others have mentioned of the rubber plug that connects the wiring grommet to the engine popping out. It did not effect performance but did not look good. The dealer fixed it under warrentee. They said it was caused by the wiring loop hitting the back of the splash well when the engine is tilted up.

johnhenry posted 12-02-2010 11:34 AM ET (US)     Profile for johnhenry  Send Email to johnhenry     
I got the same motor Sapple. I have had trouble starting it twice. 1st time, forgot to flip on the safety cut off switch. 2nd time was just a couple of weeks ago.
My mom passed away in August and my Montauk sat from early August until mid November. I had put it away in a hurry and with my mind on more important issues(if there is such a thing as something more important than my whaler it is my mother). I persuaded my wife to take a ride on the Potomac. I wanted to run some fuel stabilizer and engine cleaner into the system before storing for the winter and my mental state sucked.
We got down to Gravilly Point Ramp (next to Reagan National Airport) and were able to launch almost immediately. When my wife is with me I normally let her hold the ropes and as the boat comes off the trailer let her walk it down to the end of the dock and tie up. Parked the van, went down the whaler, put the key in, and weak crank went to no crank. Doh! That's what happens when the battery doesn't get disconnected for 3 months. Gol darn engine. Why didn't it let me know that I was supposed to disconnect the battery while sitting for 3 months, or even let me know that it is always a good idea to have an extra battery, or at least jumper cables with me? Damn Mercury! Who do I write to?
There was a good ending to my story. A nice man and his grand daughter launched right after me with an older boat(forget what it was) with a sterndrive. After he and a bass boater gave me a whole boat load of good natured grief over not having a spare battery he went and pulled a set of jumpers out of his car and hooked me up to one of his three in sequence batteries. After sitting for 10 minutes I got enough juice in the battery to start the engine. Off we went on a beautiful fall afternoon down the Potomac.
My mother would have been proud! LOL!
I will never forget when I was very young we had a 13, and we sheared a pin on the old Seahorse. My mom always took us fishing, skiing, and scalloping. Dad was never around. She hopped in the water, replaced the sheer pin and we were back in action within minutes. I was never more proud of Mom.
sapple posted 12-02-2010 03:50 PM ET (US)     Profile for sapple  Send Email to sapple     
johnhenry, it appears we boat in similar waters, I frequently boat on the James and York rivers with occasional ventures out into the Chesapeak Bay. Other than running aground, my second biggest fear is a dead battery. I keep a spare on board but have never used it. I am too lazy to disconnect the battery for the season but about once per month during the winter, I hook up a charger to the main and spare batteries until they are fully charged. So far, so good. Do you know about how many hours you have on your engine?
johnhenry posted 12-02-2010 05:33 PM ET (US)     Profile for johnhenry  Send Email to johnhenry     
Scott, I have maybe 130-140 hours on it. I guess my Smartcraft [NOTE--Here we are talking about a completely different motor than the initial topic because the motors we are talking about never had Smartcraft--they were not Mercur power head motors--jimh] system will tell me if I can find out where to look. It would be more but because of my Mom being sick I was very limited. Didn't get out to fish even once on the bay. If you ever get up a little farther north, let me know. We could plan something. Next year I expect to spend a LOT of time on the Montauk.
sapple posted 12-02-2010 07:46 PM ET (US)     Profile for sapple  Send Email to sapple     
johnhenry, I plan to bring your post to my wife's attention. She worries that the Montauk may not be enough boat for the Potomac. However, you seem to manage it.
jimh posted 12-03-2010 04:10 PM ET (US)     Profile for jimh  Send Email to jimh     
I think the more recent postings here are way off topic. Mercury created a new 115-HP motor a few years ago, a derivative from their VERADO motor but without the forced induction, without the digital throttle and shift, and without the electro-hydraulic power steering. We call these petite VERADO motors the VERADITO motor--the little VERADO. It replaced the Yamaha-Mercury Frankenstein motor we were talking about when this thread started six years ago. One of the problems of reviving a six-year-old discussion is that models and names might be the same--especially with Mercury--but the motor has changed substantially. When someone talks about a 2004 Mercury 115-HP motor it is a completely different motor than a Mercury motor purchased recently. I can't use a "model year" designator with Mercury because Mercury does not use model year designations, and now we cannot say something as simple as "a 2008 Mercury 115-HP FOURSTROKE," because there is no such thing. Mercury just sells a "115-HP FOURSTROKE" and there is no model year associated with it. This adds to the confusion.

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.

[Thread closed.]

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