Heating a Flywheel ?

[boscoe99]

I read on another forum not to use heat to help with the removal of a stuck flywheel.

The flywheel of the F300/F350 gets so hot naturally that it damages itself. I am guessing that they all get hot.

Is there anyone with an infrared temperature gun that can shoot the center of their flywheel after the motor has been warmed up and run for a good while so that we can see what the temperature may normally be?

[walleye1]

Why doesn't yamaha use a alternator instead of a stator on there bigger v6 and v8 engines?

[99yam40]

I have heard not to hit on the puller bolt, but no heat is a 1st for me
I do not own a ray gun.

I would think Yamaha would put some holes in the flywheel to force some air circulation while the thing is turning.
might whistle a little tho.
Boscoe look at my solar panel thread to see what that is in the pic I posted

[fairdeal]

can and will do it - but don't know when;
brisk winds here, the boat is up on the dock.

The temp sensor on my F225txrd - in the top of the block, just below the flywheel -
has gotten to 205 F running -

have to imagine if i shut it down right then:
no more air flow through the cowl,
"heat rises" - flywheel would easily be > 200 F
but is that "hot" ? to flesh, sure - but does it matter to the flywheel?

I just learned that while Marie Curie was killing herself studying radiation,
her husband was working on magnetism -
and the "Curie Temperature" is the point that a magnet permanently becomes un-magnetized

at a quick glance I'm seeing enormous range of Curie Temps by magnet type
for example:

Standard grade neodymium magnets have a maximum operating temperature of 80 C (176 F)
When heated above this, they will experience irrecoverable losses in performance

in contrast

Any of the Alnico magnet grades commercially available can operate in temperatures between 400 and 450C,
some of the higher grades can even operate in temperatures as high as 550 C,
meaning they are the only suitable option for applications with an operating temperature about 350 C.
Alnico magnets can continue to be effective, even when heated to the point of glowing red-hot.

[boscoe99]

Hmmm. Interesting. Had not heard of the Curie Temperature.

My PMA rotor uses N45 neodymium magnets. The housing gets hot. Damn hot. Might shoot it to see what the temperature is.

Saw this the other day about a Suzuki DF250. Wonder why Yamaha does not use something similar. Particularly with respect to the V8 F300/F350.

[boscoe99]

Why doesn't yamaha use a alternator instead of a stator on there bigger v6 and v8 engines?

Damn good question.

Yamaha seems to be stuck with their motorcycle heritage. Also, why use several parts (belt and alternator) when many more parts can be used (lighting coils, rectifier/regulator, water coolers, etc.) can be used. Yams thinking seems to be if X parts are needed to get a job done, let's use X plus some more.

Suzuki and Yamaha, being motorcycle companies first, seem to embrace a PMA electrical generation system. Mercury does not on their bigger motors. Honda does not even though they make lots of motorcycles. Probably because some of their bigger models have an automotive heritage.

[walleye1]

May save some weight also.

[boscoe99]

Definitely would save weight. Costs.

R & R would be a piece of cake.

[walleye1]

No flywheel failures also.

[pstephens46]

Did I see an alternator on an F425 picture?

[boscoe99]

Did I see an alternator on an F425 picture?

Unfortunately, you did not. Looks like that bad boy is using a lot of current internally to operate itself and the engine RPM's increase. Note how the available power to the boat gets lower at the higher RPM's.

[walleye1]

I have had several flywheels that i had to heat to remove, red loctite. I was told to use lapping compound on the taper of
both tapers before assembling. {smaller engines}.

[pstephens46]

Unfortunately, you did not. Looks like that bad boy is using a lot of current internally to operate itself and the engine RPM's increase. Note how the available power to the boat gets lower at the higher RPM's.

That is interesting. The five fuel pumps perhaps.

I must be thinking of one of the new Merc models.

[walleye1]

The opti, vrod and the new pro xs 4 stroke use a alternator
1998 till now.

[rodbolt17]

not the first flywheel I have had to heat.
trick is to have tension on the puller,heat like heck on the center and tap the puller screw with a large hammer.