Yamaha,Merc,Rude,even Johnson.

[whipper]

I relize this may be a topic that can get heated but I dont entend it to be that way. With all the talk latley about pistons going on Mercs side pined and top Im wondering if all 200+HP motors that rev 6500 and up have tiis problem? I relize theres not the number of other manufacturers engines as there is Mercs on our Allisons because of weight issues and other things. Haveing said that I am interested as Im sure others are to find out if members with other motors other than Mercury have piston problems or what kind of reliability issues are with some of the other manufacturers. So I guess what Im trying to determine is what motor has the best reliability record and what the cost differance in repaires are in comparison to blown pistons that seems to be Mercs biggest problem. New or older models not older than 1995. Motors must be 200hp or larger. Again just trying to get to know all the models with out disifiering from 100 differnat threads. If any one has information on the Johnson F1 and its reliability RPM,gear ratio ect that would be an interesting way to kick this off. Pictures also if possable. Thanks James

 

[whipper]

HOWS THE yAMAHA 2.6LT f1 FOR reliability? The light f1 johnson was that a 2.7 Lt? I dont mean the v8 only motors that would work on Allisons.

 

[Rusrog]

The piston pin problem seems to be mainly a 2.5 Merc problem. I hear of the odd 2.4 having a problem but nothing like the 2.5. This is odd because it seems to NOT be limited to one piston manufacturer. 2.5 Wiseco pistons have the worst reputation but I hear of it with other pistons in 2.5's as well. Funny thing is I never heard of it in 2.4 Wiseco's and I have never had one come out of Wiseco's for my Yamaha even in high RPM situations.

As far as OMC's go I have no idea but I also don't hear of it on the message boards so I would assume that it's not been a problem.

Up to 6500 I would say that they are all good and reliable. I would also say that even up to 7500.

As far as the latest generation motors, Hard to say...

GOod topic..

 

[Darth VMAX]

Thats a good question. If you didn't have your foot in it constantly and pampered it I wouldn't think that it would be much different than a merc drag motor that is being used for "recreational" use. But I imagine that pushin a 350hp 9K rpm 2.6L Yammie to the limit would be asking for a lot of shop time. Don't know about the pins on a Yamaha, next time I talk to HT I will ask them.

I can't remember who it was, but someone pm'd me a while back and said they bought one of Hydro-Tec's F1 motors and was rigging it on his XS or SS (again, don't remember).

 

[SLOmofo]

The question isn't IF it's WHEN! Although my OMC's are pre 1995 I'm coming aboard here.
I've had both OEM and Wiesco ring locater pins come out. Both with high and low hours.
I had a list of typical reasons as to why but tossed it.

Dissimilar metals = expansion rate of Aluminum is quicker leaving steel pin loose.
Location of pin in piston in regards to port, fuel air charge cools pin if pin is in a port area.
The cut of the port. As the ring passes by a port , does the port cause the ring to rotate in it's land. If it does the ring hits the pin one side then the other rocking it back and forth, loosening the pin in it's hole.
A large ring gap allowing exhaust gasses it pass into the pin area.
Allowing the engine to run hot. Cooling system problems. Maybe a water pump that got injured by starting the engine without water in the pump housing. Maybe a pump housing gasket that is pushed out by ram effect on the lower unit.
Running the engine lean, thus hotter.

I'm sure this list is longer.

I'm guilty of probably all on this list. Most of my pin failures would fall under the lean and water temp.

One of, in my opinion, the main contributing factors is not allowing the engine to fully warm up and then accelerating. An engine has to warm up at least 10 minutes and be at least 100f degrees. I am guilty of running around on the lake then sitting for a while then starting and running again without a new warm up period.:idiot

 

[whipper]

Good analogy Slomofo! Ya know it takes common sense to figure out most problems thats why Merc hasn't fixed the issue to many engineers thinking way to much. I dont hear of to many Yamahas or Evenrudes loosing pins compared to mercs and not just the high revers. Theres lots of 200 and 225,s with the limitter still intack loosing them also side or topped doesnt seem to matter. Whats a good light Yamaha turning for RPM stock or whats the hp,LT,wieght like suited for an Ally? Do they have a 225-250 light enough. Is there simple mods that really make a differance with them to compare to Merc in performance yet still retain reliability.

 

[Rusrog]

Whats a good light Yamaha turning for RPM stock or whats the hp,LT,wieght like suited for an Ally? Do they have a 225-250 light enough. Is there simple mods that really make a differance with them to compare to Merc in performance yet still retain reliability.

A good stock Yamaha proV200 should be able to turn up around 7000 pretty easy with nothing more than disconnect of the rev-limiter. My last one would turn 7400-7500 pretty much any time and with a bit of compression and some jetting it would turn 8000 set-up for 1/8th mile racing. I know of several finger ported motors that turn deep into the 9000 RPM range with no problems...

They are about the same as a Merc. Throw a bit of compression, some good reeds & cages, some 34mm carbs and a decent tuner and BAM! You got a runner that makes big torque with low maintenance.

And weight wise they are comparable to a 2.5 Merc. Some of the cowls were pretty heavy but HydroTec can fix that for you...

 

[brotherxb03]

Ugg, Wiseco piston's not good for outboard. Also 7K not good for stock yamaha piston.

 

[Rusrog]

Ugg, Wiseco piston's not good for outboard. Also 7K not good for stock yamaha piston.

Well I'm not sure but I think it's the way people try to run them... (The exception of course being the 2.5 Mercury Wiseco's... They are just born to fail.)
We run our Wiseco's with a lot less clearance than most and have had no problems to date in both ported and stock engines.

I don't know which pistons you are using but I have had great luck with Yamaha stock pistons to the mid 7K range. They hold up rather well. Higher than that & I always go to a Wiseco. Of course... We are not holding them wide open for miles on end either...