Valve dropping on Yanmar 6LY2A-STP


La Cozzi Vita

La Cozzi Vita

New member
I am about to buy a 2003 formula 40 PC with twin 6LY2A-STP. I have read about these dropping a valve and boom! There is a PIP program for Hinckley (http://portal.mastry.com/bulletins/...icted Product Improvement Program_12Jan10.pdf)

Is this a large scale problem or are we looking at a few unfortunate situations?
Is this common on Formulas?
Should I run from this purchase?
Has any one done the retrofit and what was the cost?

In other words, after reading so much negativity can someone put me at ease...
 
I don't know much about it with regards to this specific issue. The guys on Boat Diesel would be able to provide much more details.

What I can tell you is in general, diesel engines that are overloaded suffer this type of failure.

If the engine can't make full RPM, or in the case of some burn more fuel at every RPM setting than their power curve suggests they should the engine is OVERLOADED.

This drastically increases EGT's, which heats the valves and seats far above normal operation leading to failure.

Of course defective components could be something else all together...
 
I have heard of Formulas having this issue but it seems to be a pretty small number. It's all about RPM's and how the boat is driven, the high performance diesels should not be run at high RPM's for an extended period of time. I have the Yanmars and I had my prop's repitched to reach a higher RPM. I went from 3200 to 3375 and I cruise around 2400 RPM. If the previous owner liked to run them hard, around 2900 and wide open throttle is only 3200 I would be concerned.

I am considering having the heads pulled and the valves and seats changed as a preventive measure. It's a lot of money but small in comparison to a new engine.

With that being said I love the Yanmars, I'm on my third season and they have been flawless.
 
i'm confused as to why this only applies to the Hinckley's?? My first thought would be to check the serial numbers and see if they fall within the range listed. my second thought would be to contact Yanmar and ask them about it. personally, my mind would NOT be at ease until i did both of these.
 
Formula Tenn said:
i'm confused as to why this only applies to the Hinckley's?? My first thought would be to check the serial numbers and see if they fall within the range listed. my second thought would be to contact Yanmar and ask them about it. personally, my mind would NOT be at ease until i did both of these.
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I have...

The serial numbers fall into the affected batch. I called Yanmar and no call back. My mechanic called Yanmar and those serial numbers don't show up on their records. Unfortunately he feels Yanmar will not cover any upgrade or repair due to age.

I am about to pull the plug on this purchase. That will leave me out of having a Formula, since they all 40PC have them in the year range I can afford one. Sea Ray here I come...Again!
 
The Hinkley's were propped wrong from the factory and they had a bunch of failures. Your best resource is to call Mack Boring, they are the rep for Yanmar.

Did you run the boat WOT during the survey? It's hard reading about things like this on the internet, no one goes out of their way to start a discussion that says, "I ran my Yanmars for 1000 hours and the valves were OK". You are on this site and not a single person said they had the failure.

I would run from any boat that has not been taken care of, gas or diesel. A boat that is not propped right will have a short life regardless of what type of engine it has.

If I recall correctly it's about 4K per engine for new valves. Maybe the owner will split the cost with you and you can get both done so you sleep better at night.
 
I have over 900 hours. These motors have been very good to me. Only problem I had at 500 hours blew a transmission. I have heard about the Hinkley problem but don't know anything about it. Yanmar builds a fine motor.If it is well maintained it will run 10 thousand hours before an overhaul.
 
gwazoo27 said:
I have over 900 hours. These motors have been very good to me. Only problem I had at 500 hours blew a transmission. I have heard about the Hinkley problem but don't know anything about it. Yanmar builds a fine motor.If it is well maintained it will run 10 thousand hours before an overhaul.
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Hello gwazoo27,

What is your WOT RPM? What do you cruise at and what is your average fuel burn at cruise? Are your serial numbers above M56900?
 
Wot is 3350 after sending my props out. Easy cruise is at 2500 rpm 22-23 mph burning 18 gals a hour.Why do you ask the serial # I can check this weekend
 
gwazoo27 said:
Wot is 3350 after sending my props out. Easy cruise is at 2500 rpm 22-23 mph burning 18 gals a hour.Why do you ask the serial # I can check this weekend
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Never mind... I just wanted to see if your engines where post the valve upgrade. They most likely are...
 
I purchased an 04' with the Yanmars and paid to have the new inconel valves installed. I can tell you all about the process, the cost, etc. While costly, it's a worthwhile upgrade for the piece of mind alone. The engines run perfect otherwise and will for a long time, why risk a known issue that is not repairable? By the way, you won't get anything useful out of Yanmar as far as info. Their service advisory was strictly for Hinckleys and they deny anything beyond that. On boat diesel, you'll find numerous stories of Formula owners who dropped a valve at 300 and 500 hours without warning and for no reason. It's not just a Hinckley problem. By the way, awesome boat with the Yanmars, sips fuel, cruises nice, handles very well.
 
Sooliman,

Can you give us an idea of the cost for the valve upgrade? I'm expecting about 4-5K per engine but that's just a guess.
 
Nate, I apologize for the ridiculously late reply - I can't believe I haven't checked the forum since October!
I had the valves changed by Yanmar experts in Annapolis, MD at Bayshore Marine. They came highly recommended to me, I did my research and I was extremely pleased with their professionalism and quality of work. You're close on the price, but you'll be happy to know the final number was around $6k for both motors. Yes, it's a big nut to swallow, but the insurance (in my mind) is priceless, and I have low hour (300) motors on an immaculate boat - so it was worth it for me. Good luck - let me know if you need to know anything further.
 
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