Pulling flywheel on Merc 25

Carl

Carl

Well-known member
Staff member
Any advice on pulling the flywheel on my 2003 Merc 25 manual start? Mainly how to hold the flywheel in one place when breaking the nut loose? I think I can pull it once that is off.
Did the ohm test today, kill switch and switchbox are good. No resistance in the trigger, either stationary or when pulling the rope. So everything points to a bad trigger. Gotta get online and order one ASAP.
 
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Carl said:
Any advice on pulling the flywheel on my 2003 Merc 25 manual start? Mainly how to hold the flywheel in one place when breaking the nut loose? I think I can pull it once that is off.
Did the ohm test today, kill switch and switchbox are good. No resistance in the trigger, either stationary or when pulling the rope. So everything points to a bad trigger. Gotta get online and order one ASAP.
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Impact wrench to loosen the screw. Otherwise a spare set of hands to grip the OD of the flywheel and a sharp blow to the wrench to loosen the screw. I think it is a right hand thread but can't guarantee that.

The flywheel itself, sits on a taper and will most likely require a puller to break it loose. You may find 3 tapped holes in the upper surface of the flywheel. Those are for using a puller. If no tapped holes you may be able to use a puller which has jaws to engage to OD of the fly wheel. You should be able to borrow or rent a puller at your local auto parts store.

To properly use the puller. Reinstall the crankshaft screw (without the washer) except leave it about 1 to 1.5 threads from contacting the flywheel. (unless the screw head will go thru the center hole of the flywheel, then the screw can contact the crankshaft, contact is better if it will pass thru the hole in the flywheel) Install the appropriate puller and tighten the forcing screw up fairly snug. With good tension on the puller, smack the end of the forcing screw with a decent size hammer. The impact should immediately pop the fly wheel loose. If it doesn't increase the tension a bit more and hit it with the hammer again.
Do not try to pop the flywheel just by tightening to forcing screw. It's the hammer impact while under tension which does the job.

You will want to clean any rust or corrosion before reinstalling the flywheel. Do not use any lube where the flywheel contacts the crankshaft.
 
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You da? man Dave, knew I could depend on you for a good description. I owe you a beverage of choice
 
If my local marine store does not have one, anyone have a recommendation for a good marine part online store?
 
Carl said:
If my local marine store does not have one, anyone have a recommendation for a good marine part online store?
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Carl, I have no personal experience with these folks but I do see their name pop up on several boating forums. I-boats

http://ww2.iboats.com/Boat-Motor-Parts/dm/utm_medium.magento--utm_source.shop--view_id.268656
 
Carl,
I did a real quick look up of the trigger assembly on I-boats, about $70.00 if I looked under the right engine. (didn't go back and check your numbers) Hope that's it, the switch box is a whole lot more $$. [;)]

PS, you type faster than my hunt peck method.
 
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Carl said:
I owe you a beverage of choice
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Carl,
I'd settled for you getting Mark W to send some of those Mallards he is "short stopping" up there in MN, down my way. I promise to send most them along your way.

I did have a pair come in today. The Suzie is headed your way but the greenhead stayed behind. [;)]
 
Carl, iboats is good, they have one of the best. DIY forums. I run/fix only Johnson/Evinrude, use Seaway Marine a lot although Seaway recently stopped having Parts diagrams online. Also used Marineengine.com Seaway website indicates they handle Mercury parts too. Dave McCann technique is same as mine--keep in mind the flywheel may come off the tapered top of crankshaft with a minor "explosion".
 
Huntindave McCann said:
Carl said:
I owe you a beverage of choice
Click to expand...

Carl,
I'd settled for you getting Mark W to send some of those Mallards he is "short stopping" up there in MN, down my way. I promise to send most them along your way.

I did have a pair come in today. The Suzie is headed your way but the greenhead stayed behind. [;)]
Click to expand...

Ok, I promise starting today I?ll. Or ?short stop? any more mallards.

Mark
 
Local shop has one in stock for $80, I'm going to pick it up today.
Hopefully up & running when the split comes back in here on the 7th.
 
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