1977 50hp Mercury flywheel removal

garyd13

Recruit
Joined
Jan 26, 2016
Messages
2
best way to remove flywheel without damage. i am currently replacing original wiring Thanks
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,585
garyd13, :welcome: to iboats. Glad you could join us...

The usual way to remove an O/B engine's flywheel is to use a flywheel puller (harmonic balancer puller) that has three legs. Each leg is bolted into the three threaded holes on the top of the flywheel. And the center bolt is then tightened down until the flywheel breaks loose.

There are many threads on these forums that cover this subject in great detail. But some times flywheels are very stubborn to come off. So it takes some effort to remove them. First thing you need to do is use grade 8 bolts and thread them in about 1/2" into the flywheel. If you go in too far it will thread through and possibly damage parts underneath the flywheel. So only thread the three bolts in only so far.

And once you applied all the torque you can to the center bolt, take a hammer and whack the center bolt to help break the tapered flywheel off. Some times it takes a lot to remove them. And when they do break loose, it sounds like the flywheel has broken. But it is just the sound of it breaking loose.

This is the type wheel puller you need to be using with grade eight bolts. If you try to use other bolts, I can guarantee you they will either break, or strip. Been there and done that! So save yourself some time and headaches and buy grade eight bolts to start with. :thumb:

Z_8ODvfo5oy.JPG
 

garyd13

Recruit
Joined
Jan 26, 2016
Messages
2
Thanks gm280 your help is appreciated just learned of this site yesterday !! Think it will be a great site Thanks again
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,051
The MERCURY flywheels use one big internal thread for use with a puller.---Some of their flywheels can be pulled using 2 bolts.--Remove 2 of the bolts on the flex plate and use those to pull it off.
 

tommarvin

Ensign
Joined
Nov 22, 2015
Messages
999
All I know is don't use the three jaw puller,
We had to heat around where the flywheel and drive shaft meet with propane for two minutes gently tapping drive shaft every two seconds it finally broke free.
Are you replacing the wiring on the trigger and stator?
CDIelectronics.com is the king of ignition parts.
Free factory service manuals at www boatinfo.no/lib/library.html click make
 
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