View Full Version : Flying Flywheel Magnets

09-11-2009, 07:57 AM
Hey all,

I have a mid 80s 90HP Oil Injected 2 stroke Merc, which i has been very temperamental in her operation over the past few months.

I was out on p/passage on friday and i hit something on my way home and bent up the prop. After taking it off and straightening it out again, last night i put it back on, and had the cowling off to reconnect the plugs.

So after getting it back on, i kicked over the engine and started to idle. As i was watching the cowl-less engine, i noticed a small bit of metal come flying out from under the flywheel housing. Sure enough, i moved a little closer to see what it was, and another came flying out, bounced off the block and hit me between the eyes. >:(

I turned the engine off, and had a bit of a look, and the flywheel magnets were falling out from under the flywheel. I removed three bits, about an inch and a half in total, and a lot of filings. I havent taken the flywheel off yet, so i am not 100% sure on the extent of the damage.

So, not knowing much about engines, am i right in saying that the magnets on the fly wheel are a part of the system to generate current that ultimately fires the engine? so with out them, i am stuffed?

Are losing magnets a common event? And are they easily replaced?

Any help would be most appreciated. cheers.

09-11-2009, 06:02 PM

Had to replace the flywheel on my Honda 40 last year as the pads on the flywheel had started to come away and rub. The engine had started making a whirring noise which alerted me to the problem early enough before totally coming away. Wasn't cheap unfortnately......


09-11-2009, 07:16 PM

Not all that uncommon on these.Firstly your engine you will find is later than mid 80's, if it is a autoblend with the oil bottle in the boat is somewhere toward late 80's but if it is a 3cyl 90hp with the oil bottle just foward of the starter under the cowl it is most likely at the oldest early 90's.If yours is the 3cyl 90hp with the bigfoot gearbox they are a bloody good motor with proper care.

You will pick up a secondhand flywheel on e-bay for not much at all just be sure to get one for your number of cyl's, have seen many buy a flywheel thinking one size fits all but this is not the case at all i.e timing marks etc.



09-11-2009, 09:51 PM
yeah, thats it steeler, 90 hp 3 cl with the oil bottle in the cowl. It sat unused for years before i started playing with it, and it started first time, so i am keen to get it back to its former glory...

Just been looking online and there seems to be a good supply of parts around, so hopefully i can fix it up.