Both magnetos cracked!!

wiboatergile

Seaman Apprentice
Joined
Jun 19, 2007
Messages
39
:eek: Finally got back to the 18hp johnson. Got the inspection cover off the flywheel and noticed both magneto casings cracked. Points and condensers look recent but will change them anyway. Now to find someone with a flywheel puller.. I believe this is why #2 cylinder doesnt fire. Does anyone think the local Johnson dealer would pull the flywheel for me. Or should I just ask them to replace and set timing on it.. Just a thought..
 

BoatBuoy

Rear Admiral
Joined
May 29, 2004
Messages
4,856
Re: Both magnetos cracked!!

Puller - $9.99 at Harbor Freight

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Put it back together with the new parts and timing will be OK. There's really no adjustment.
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: Both magnetos cracked!!

what you are calling magneto are actually the coils. a simple harmonic balancer puller, with 3 # 8 harden 1/4 x 20 bolts and washers, will pull the flywheel. have to use the # 8 bolt because the standard bolt will strip off in the flywheel. auto parts store has the bolts.

typing at the same time
 

wiboatergile

Seaman Apprentice
Joined
Jun 19, 2007
Messages
39
Re: Both magnetos cracked!!

Called them mags outta habit as they look the same as the ones in a P250 pump the US Navy used when I was in. Hope this solves most of the probs with running on one cylinder.. Thanks for the Info guys...
 

BoatBuoy

Rear Admiral
Joined
May 29, 2004
Messages
4,856
Re: Both magnetos cracked!!

They may be the same. I understand OMC made quite a few pumps used by the Navy.
 

fishchaser

Cadet
Joined
Jun 17, 2007
Messages
23
Re: Both magnetos cracked!!

what you are calling magneto are actually the coils. a simple harmonic balancer puller, with 3 # 8 harden 1/4 x 20 bolts and washers, will pull the flywheel. have to use the # 8 bolt because the standard bolt will strip off in the flywheel. auto parts store has the bolts.

typing at the same time

tashasdaddy,
I went to my local hardware store tonight and bought 3 Grade 5 bolts (1/4 - 20) to use with harmonic balancer puller. Wanted Grade 8, but they didn't have them in a long enough length. Do you think I'm risking damaging my magneto by using the Grade 5 bolts?
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: Both magnetos cracked!!

Dude (and TD), Grade 5 will work fine. Now WAY they will strip out the FW, any easier than Grade 3. 5, or 8 will..ya just have to do the following (Machinist all my life) ..... ..tighten them snug, then tighten the center screw super snug ...strike it with a 5lb or better sledge. Don't beat it down ..what you are looking to do is shock it off the taper. Rap, tighten the center screw down again, rap...it will pop off..its the shock that breaks the taper..not the puny 1/4 bolts..I've done enough Flywheels that I just stick a heavy duty screwdriver under the flywheel and a solid piece of motor block, crank nut almost flush, and rap the SOB my my 20 pounder. But it takes a lot of doing it before ya get the feel..talking lots of years here..(yeah...busted a few wheels too!)

Stop saying magneto...a mag is a self contained magnets and rotor...you don't have one..its the coils that are junk...you will find many small pieces of the coils when it comes off. $40 for 2 new coils, ya back on the water again. Hers what you will find

PICT0009.jpg
 

fishchaser

Cadet
Joined
Jun 17, 2007
Messages
23
Re: Both magnetos cracked!!

Hey Scaaty,

Looks like you got a picture of my motor. My coils look just like that. New ones on order. Thanks for the info about the bolts.
 

wiboatergile

Seaman Apprentice
Joined
Jun 19, 2007
Messages
39
Re: Both magnetos cracked!!

:eek: Thank god mine arent that bad yet!! But that is pretty much the motor, right down to the throttle cam roller poking its head up.. Ah another topic on how to adjust that coming after coil and related electrical repair..
Thanks for info on bolts just in case cant find grade 8 around here in podunk...
 
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