Back when engines had carburetors and car engines in boats had open ignitions...
Yes, that's when and why boats were blowing up and blowers became mandatory in boats. And that was a good thing.
Now, fast forward few decades to today.
In your new E-series Yamaha - blowers are nothing more than a holdover from the bygone era of those old boat power plants.
Fuel vapors coming off a fuel injected engine... I don't think that actually exists in FI engines (assuming it's working properly - or you have bigger problems that a blower is not going to solve) and the ignition systems are sealed - you just don't have the vapors and the ignition sources you had before.
Once you start and run - the engines are giant air pumps that move thousand times more air throught he engine comp/bilge than the silly little RULE blower... Which, BTW, hardly moves any air anyway.
I have looked into those issues, a lot, when doing my first ribbon delete (there are still those here who will tell you your boat is going to blow up when you remove the ribbons as those are also flame arrestors
). I happen to have family who often rides with me and no intention to blow my boat up. So - I researched that topic to death, talked to many people way more knowledgeable; concluded this whole idea of ribbons being needed to arrest flames in a fuel injected engine is... pure baloney.
As a side note:
Yeah, we all heard of jet skis blowing up in smoke. Usually a result of a gross neglect/pools of fuel leaked into the little bilge/etc. - I do not believe the stupid little Rule OEM blower would help much in those cases. Would it?
So yes, I do think those OEM blowers are... useless. And awfully loud. And yes, they are required by law.
If you want a real blower, I think @gmtech had moded one that was 6/12v whisper quiet one that was rated something like 10x the volume of the OEM air moved. I would do that, maybe.
In the meantime - the little OEM thingy does nothing to improve our boating safety.
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