Derek, Thanks for the comment. The problem is not the flywheel, it’s a harmonics issue in the crack shaft of the F350, from what I’ve been told by Yamaha. Over time, theses harmonics can loosen the magnets in the flywheel. That is the reason for the flywheel replacement. As for how often the FW has to be replace, I just sold a boat with twin F350 that had 285 hours since a FW replacement and there had on been 60 hours put on the FW in the RPM range that is a concern. So for the average boat, that means the FW gets replaced about ever two to three years. And this is done for free for the owner. Yamaha was already working on the next gen V-8 (425 XTO), so really they were already working on a redesign.
In UK you could opt for just the flywheel service and get loads of free maintenance from yam dealers Or if you were operating it in harsh environments they would do a recall job and replace the entire crank assembly. I got told most opted for just the flywheel swap to get all the free perks.
This just doesn't make sense to me. Why is this the only motor you've ever heard of needing a new fly wheel after so long running in certain RPMs? That is crazy. Redesign the flywheel or the magnets, or whatever. How the hell is the fix "bring it in once or twice a year and we'll give you a new fly wheel"? I'm sure this motor is boss, but what a turn off......that NO OTHER motor has
It’s a crank balance issue apparently because the magnets balance loose. That’s much cheaper for Yamaha than a crank rebuild!!! So replacing a flywheel is easy and cheap!
I don’t get all the Yamaha Hype and I’m a Merc guy all the way. 350 hours on my 150 4stroke, in 1 year and should easily be able to get another 5-7 years of same usage out of it.
The motor is a monster I have twins on 35zf donzi they are great extra quiet at idle. Having to get the flywheel done for free every 2-400 hrs is no big deal your motor will always need some maintenance this is a 1 hr job for free that replaced a part that’s always a good thing you basically have a fresh flywheel and computer update every 2-300 hrs! That’s a good thing
You are all talking mince. Yamaha and Jonnyrude are by far the most reliable. Then suzuki are 3rd best. Merc are a joke they get constant issues after a few year. These are facts not opinions lads. Merc used to be half decent reliability back in the 80s but even then they were nowhere near jonnyrude and yamaha reliability. Here in the UK merc are considered useless as they simply don't last in the North Sea. Modern mercs are attrocious reliability since they have sneaked more and more chinese parts on them. See Parsun engines they are a copy of yamaha that use some Chinese parts and even they have less chinese parts than the equivalent mercs, they are twice as reliable, haul better for the hp and are half the price. Don't take my word for it I'm only a 4 decade boat builder.
Just spoke to our yam rep about this on WhatsApp to check what the real story is. See in UK this engine the dealers offered two packages as a fix, there was a full recall where the full crank assembly was replaced, they recommended this if it was used in seriously harsh environments. The other option was the service option with the flywheel change but a lot of people chose that as it had loads of servicing perks and you got a lot of maintenance done for free. I'm not sure if this is the same anywhere outside UK but I'd presume so.