I have noticed a direct relation between outboard motor problems and the junk we are using for fuel and to add all of the additive`s in the world will not help bad fuel. The low quality fuel mainly causes detonation in these high performance motors. It destroys the piston ring lands, head gaskets, "O"rings and any gasket that comes in contact with the fuel. I remember engineers warning about the coming effects of ethanol 20+ years ago.

I have a 2012 SHO on my Z521, good fuel(I run Premium. always have in every boat owned), fuel treatment in every tank, and in 39 years (knock on wood), never an engine issue. I have had Mercury's all my life and went to the SHO on this one. Great engine, quick, and SECRET to idle on a SHO is to trim up when idling. It doesnt like down fully down position. Trim it up a quarter of the way and it will IDLE smooth ALL DAY LONG.
Gary's comments above are RIGHT ON!

I am shopping for another newer boat. I am trying to decide which brand to go with. I recently asked a respected marine tech about this and after my question he replied with his answer. It's definitely not what you would call objective but this is how it went.
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For starters I'm not sure you are the one I should be asking this question but your input will be helpful. My current rig is an 04 champ 187 with a carbed Merc XR6 150. I've been in this since 05. The outboard has been a trusty workhorse. I am shopping for a used 08 or 09 champ 210 with 250 hp. I've never had an Opti or Pro XS or a Yamaha. Most rigs I locate for sell have the Pro XS 250. Some have the Yamaha 250 HPDI Series 2. I really don't know the pros and cons of either motor. Will these two motors perform differently on this 210 hull? In the past I've been enamored with the Yamaha motors but not with any real reason. I guess I am trying to rule in or rule out the Yamaha. Since this is new territory for me and I am not a gear head I just want to be satisfied and not regret my choice. I just don't know how the two motors compare on performance and reliability. Are you able to comment ? I know you have a vast experience with the Mercury motors but I really don't have any with the Pro XS or the Yamaha.
Thanks


RESPONSE

In my 37 years, I've serviced nearly ALL brands of engines (please don't publish that, BTW... I have enough to do with the Merc guys).

I wear black shirts for a reason... we've had offers from the blue guys, the white guys... but Mercury's committment to their product (and their customers) is second to NONE.

You would be VERY happy with the ProXS... it's got unbelievable fuel economy (you'll likely use about the same as you did with your XR6, believe it or not).

VERY powerful, good track record, and parts are almost always readily available (seldom to you wait on two guys paddling a canoe across the ocean with parts).

If I was buying a new or barely used (2-3 years old or less) motor today, it would absolutely be a Merc (if we're only choosing between Yamaha and Mercury). I've got a '97 Evinrude that hasn't missed a beat in 16 years, so I'm not looking to upgrade. But it seems like we hear way more stories about the SHO blowing up than any of the newest Mercs. Sure maybe it�s anecdotal, but it�s all I�ve got to go off of and he�s asking for opinions.

Not "knocking" the Yamaha SHO but Yamaha is having the early design problems similar to the Mercury Optimax in it's early years. After Mercury got the bugs fixed they changed the name to the ProXS and it is now a very good and reliable engine. When Yamaha get's their bugs fixed I am sure that the SHO will be as reliable as the ProXS. At this time it would probably be best to stick with the Merc as a more proven and reliable model.

On the SHO engines, seems like the talk about "blowing up" is from 2011 and older engines. Has anyone with a newer version say the 2012 & 2013 boats seen the same issue? How many of you who have had the SHO "blow up" have had the same problem on the second engine? Reason I ask is that I was told by a certified Yamaha mechanic at Texas Boat World is that these engines are now sound and among the better engines on the market? There had been an oiling problem and now that is all fixed?

What I've learned after 35 years of fooling with Johnson, Suzuki then Yamaha and now Mercury is........

they all blow.

Pick one you like and go fishing.

FALSE....... you can buy 2013 proxs optimax and 2013 optimax engines. there is very few differences but not all the new ones are badged PROXS...... one difference i know for sure on the different models is the reed system, one is stainless and one is carbon fiber allowing for faster throttle response.

It's funny how easy we forget the Mercury coil problems that were only fixed a couple of years ago. Those coils caused a lot of downtime.

Thanks for the opinions guys and thanks for keeping it civil.

I will try to find out more about what part of the head failed and what the exact repair is. (initially, I was mostly concerned over pressuring them to diagnose and get parts ordered.)

The fact that no motor likes to idle really worries me when I side scan. I scan A LOT to find fish. I will certainly raise it at idle now and run it like I stole it a bit more when I get it back.

One observation I agree with is it seems the last few years of Pro XS have really gone well (after they worked all their kinks out).

I had about the same amount of hours on my 200 Opti when a rod went through the power head. Luckily I had an extended warranty and Merc treated me right. I never saw a bill. That said, were I re powering today, it would be a 4 stroke, probably a Yammy.

Everyone I know that has a SHO has had it blow, some even twice!

I know what their charts say. And, that is what I did prefishing to conserve fuel. This was my own personal experience with my SHO.

"....does not like to idle...."
This would really torque me off if I had the money to buy a new Ranger, with all the latest electronics and a big 4-stroke engine.
Idling around and looking at my graphs, and punching-in waypoints, is something I would want to do a lot of the time.
OK, so all I've got is my (bought-new) 1990 Ranger with Merc XR-4 150. And, I can tell you it does not like to idle around either. But, the reason is that the water circulating/cooling system is NOT up to cooling the engine when running around at idle. And, it's even worst when running around at slightly above idle. Yes, I change the impeller.
So, what's the reason for a mega-buck modern engine not to like idle speeds?

In regards to the SHO engines, the "break-in" period is criticial to the engines longevity and dependability. The motor needs to be ran hard and hot to seat the rings in. If they are not properly seated, when you idle fuel will get past the rings and into the crankcase. This is where you get the term "making oil." It's what alot of the early SHO's had problems with. From what i've noticed, guys that run them hard do not have the problems that guys who idle alot do.
Once the motor is properly broken-in, theoretically you should not have idle problems.