Yamaha 350 - resonant torsional vibration

[Sugar Cane]

new pictures now uploaded to an Album (I wasn't sure how to upload ot the thread)

[Last Tango]

Originally Posted by Xk59D

"80 hours in the 3200-4250 range and flywheel will require replacement"

At least once a year.....

I'm guessing you meant 3500hrs (or 43 flywheels) "10 years" that'd be 4 a year.

So Yamaha are going to come down to the marina. or whatever remote place you might be, to replace it........how many days are you going to have to give up trailing it back and forward to the dealer? Frankly, I'd have given it a wide berth. There are plenty of other engines out there that don't demand that kind of pampering.

[Last Tango]

Originally Posted by beamishken

The problem seems to relate to prolonged running at a certain rpm which will be one or both of the harmonic vibration sweet spots
The flywheel must be some kind of dual mass damper affair & when the damper is doing its job for long periods then it will deteriorate. Many engines can suffer from harmonic vibration when run at continuous rpm for long periods
Some dampers can actually get so hot they discolour due to harmonics
It seems yamaha have found a potential problem and addressed it by offering free replacement if the engine ever reaches the set hours at that rpm
In the US owners may hit the required hours as they tend to do long hours running at continuous speeds however in the UK for a leisure user it's probably unlikely to reach those hours for a very long time
Many engines in the marketplace have common failure points eg bmw 5 series timing chains snapping or swirl flaps dropping onto pistons both destroying engines
I'm sure outboards from other makers will have common failure points too
This problem seems to have been identified & measures put in place to prevent the owner getting a nasty surprise or big bill
Enjoy the boat and forget about the flywheel!
Personally I don't think there is much in the market place to better yamaha so if I was in the marker for that size of engine I'd happily buy one

RTV (resonant torsional vibration) in piston engines is a well understood problem and other manufacturers get round it without needing the flywheel replaced 40+ times in the engine's life. Jaguar scrapped it's first attempt at a V8 because of this and started again.
This is the consequence of a fundamental schoolboy error in the engine design and it should have been sorted long before the it went in to production. I really can't see how Yamaha can think this an acceptable solution. Other engines do have their problems but keeping replacing the bit that breaks isn't a fix.

[beamishken]

Originally Posted by Last Tango

At least once a year.....

I'm guessing you meant 3500hrs.

The average use of a UK leisure boat is around 50 hours per year therefor it will take most average boaters several years to accumulate the 80 hours required at the specific rpm range.
The sensible thing would be to avoid that rpm range
Lots of engines suffer from harmonic vibration, 6lp yanmars can snap cranks due to it,yamaha have identified a problem and offered a no cost solution for the owner.
Most engines require annual service or 100 hours whichever is sooner so engine should be in for service well before required hours are accumulated at specific rpm so no need for extra time in dealers as replacement can be done at service time

[Xk59D]

Originally Posted by Last Tango

At least once a year.....

I'm guessing you meant 3500hrs (or 43 flywheels) "10 years" that'd be 4 a year.

So Yamaha are going to come down to the marina. or whatever remote place you might be, to replace it........how many days are you going to have to give up trailing it back and forward to the dealer? Frankly, I'd have given it a wide berth. There are plenty of other engines out there that don't demand that kind of pampering.

To clarify every 80 hours it needs replaced basically to keep it simple.

I would bet after 10 years the problem is yours as the epa is 10 years rating.

[69cmw]

Originally Posted by Last Tango

RTV (resonant torsional vibration) in piston engines is a well understood problem and other manufacturers get round it without needing the flywheel replaced 40+ times in the engine's life. Jaguar scrapped it's first attempt at a V8 because of this and started again.

This is the consequence of a fundamental schoolboy error in the engine design and it should have been sorted long before the it went in to production. I really can't see how Yamaha can think this an acceptable solution. Other engines do have their problems but keeping replacing the bit that breaks isn't a fix.

It's not your engine so you don't have to worry yourself ...

[beamishken]

Originally Posted by Xk59D

To clarify every 80 hours it needs replaced basically to keep it simple.

I would bet after 10 years the problem is yours as the epa is 10 years rating.

No it doesn't need replaced every 80 hours
It needs replaced when it's ran 80 hours at a specific rpm range which the ecm keeps tabs on therefor it could in theory need replacing at 80 hours but it could potentially never need replaced

Wtf is wrong with you guys the op has just joined and is obviously delighted with his new boat and all
Xk59D and Tango can do is slag off his engine choice
Sometimes if you don't have anything good to say it's better to say nothing!
Maybe a bit of green eyed monster about here
Enjoy the boat forget the flywheel and the negativity

[beamishken]

Originally Posted by 69cmw

It's not your engine so you don't have to worry yourself ...

Well said!

[Xk59D]

Originally Posted by beamishken

No it doesn't need replaced every 80 hours
It needs replaced when it's ran 80 hours at a specific rpm range which the ecm keeps tabs on therefor it could in theory need replacing at 80 hours but it could potentially never need replaced

Wtf is wrong with you guys the op has just joined and is obviously delighted with his new boat and all
Xk59D and Tango can do is slag off his engine choice
Sometimes if you don't have anything good to say it's better to say nothing!
Maybe a bit of green eyed monster about here
Enjoy the boat forget the flywheel and the negativity

I don't how you would know, you clearly haven't researched it and came from a fan boy angle the whole thread, yet I'm the bad one for suggesting the op gets something in writing for his probably 25k engine, get over yourself.

[beamishken]

Originally Posted by Xk59D

I don't how you would know, you clearly haven't researched it and came from a fan boy angle the whole thread, yet I'm the bad one for suggesting the op gets something in writing for his probably 25k engine, get over yourself.

If you actualy read the ops post #17 then the info is there
Perhaps you need to go to spec savers or maybe you just like knocking people's new very expensive purchase! Without reading their responses
Think it's you needs to get over yourself

[Xk59D]

I don't need to goto spec savers to spot a fan boy thanks......spotted weeks ago.

The OP is happy, he said so earlier so all I done was clarify what LT said.

If someone is lucky enough to buy a 350 then at least they know what to expect as yamaha uk never mentioned a peep.....

[beamishken]

Don't even know what a fan boy is but I can tell when someone is trying to piss on someone else's chips which is exactly what you've been doing throughout the thread
A nice welcome to a new member!

[Xk59D]

To the OP, I sincerely wish you many happy miles in your new toy and if I came across as anything other than being concerned a new owner is tossing money away potentially without some answers then for that I apologise to you.

[Last Tango]

Originally Posted by beamishken

No it doesn't need replaced every 80 hours
It needs replaced when it's ran 80 hours at a specific rpm range which the ecm keeps tabs on therefor it could in theory need replacing at 80 hours but it could potentially never need replaced

Wtf is wrong with you guys the op has just joined and is obviously delighted with his new boat and all
Xk59D and Tango can do is slag off his engine choice
Sometimes if you don't have anything good to say it's better to say nothing!
Maybe a bit of green eyed monster about here
Enjoy the boat forget the flywheel and the negativity

When someone asks for advice, trying to blind them ill founded brand loyalty is not advice, it's canvasing.
The rev range where this engine appears to have the problem is the range where it will spend 90% of it's time running and I don't know where you're getting the 50hrs/yr figure. This boat is plainly a substantial investment and I'd be expecting to do at least twice that (and in the rev range where the problem is). As for "forget the flywheel", the warning light popping up when you're 60mls from shore might be something of an unpleasant reminder. The OP asked for advice and our advice was that there are engines that don't exhibit this or other serious issues that might be worth considering. It's not an "anti-Yamaha" rant, and it's absolutely NOT about having a go at the OP.
There's a saying "if you're happy with the deal, you got a bargain" and that's where the OP is and I genuinely hope he remains so. Obviously he's ok with this, I wouldn't be, if for no other reason, because of the investment in my time and effort dealing with it, however maybe that's just me.

[willk]

Originally Posted by Last Tango

When someone asks for advice, trying to blind them ill founded brand loyalty is not advice, it's canvasing.

And I'm not seeing either of those things here (where I've had to move it). There was a lot of unadulterated drivel being posted about Yamaha 350s needing a new flywheel every 80 hours - which is patently tosh. You're all entitled to an opinion and a reasoned debate, which you can still have if it remains reasonably civil. But when/if the first haggis gets cast yer all off to the bilges and/or a nice lie down for a while...

[Xk59D]

Willk, i don't wish to keep this going but i object to a mod calling what is posted as "tosh" and "drivel" when what is posted was proven correct in part, if not entirely.

as i posted previously, this is from a yam bulletin in USA-

"80 hours in the 3200-4250 range and flywheel will require replacement"

that was dated 2015, things may have changed now ofcourse in USA.

we don't know what the UK deal is of course but probably similar to our friends across the big pond and at the very minimum the OP got an answer from Yam UK they are happy with, our other member was not so lucky last we heard, so progress was made.

i take onboard your point about being civil and again sorry if any offence caused.

if you want more info then google is the place, i'm not getting involved anymore you will all be pleased to know

[69cmw]

Originally Posted by Xk59D

Willk, i don't wish to keep this going but i object to a mod calling what is posted as "tosh" and "drivel" when what is posted was proven correct in part, if not entirely.

as i posted previously, this is from a yam bulletin in USA-

"80 hours in the 3200-4250 range and flywheel will require replacement"

that was dated 2015, things may have changed now ofcourse in USA.

we don't know what the UK deal is of course but probably similar to our friends across the big pond and at the very minimum the OP got an answer from Yam UK they are happy with, our other member was not so lucky last we heard, so progress was made.

i take onboard your point about being civil and again sorry if any offence caused.

if you want more info then google is the place, i'm not getting involved anymore you will all be pleased to know

It's not your engine so I wouldn't bother getting your knickers in a twist about it ...

[willk]

Originally Posted by Xk59D

"80 hours in the 3200-4250 range and flywheel will require replacement"

Absolutely. Anyone with real world experience of OBMs knows what that means. It certainly doesn't mean the flywheel needs replacing every 80hrs. IMHO, that makes any claim that it does - "tosh" or "drivel". I'm happy to be corrected but I'm not holding my breath...

[willk]

Originally Posted by 69cmw

It's not your engine so I wouldn't bother getting your knickers in a twist about it ...

Was there a haggis thrown there? I'll be inconsolable if there was?