Getting flywheel off

[Gary H NC]

1991 3 cylinder 75hp. What are the chances of using an impact to get the nut off and not needing a puller for the flywheel?
I notice the Merc shop manual shows using the threaded puller in the large hole after the nut is removed.
Any other type puller that works?
Anyone know the size of the flywheel nut?

THANKS!

 

[walleye1968]

Re: Getting flywheel off

you can use a air impact to get the nut off
you will stil need a puller the thread puller is best but you can use a steering wheel puller will work
if you use the wheel puller do not thread the bolts in to much
thay will hit the trigger coil

 

[Gary H NC]

Re: Getting flywheel off

Thanks Walleye,
Do you know the size of the nut?

 

[j_martin]

Re: Getting flywheel off

Go ahead and use the impact wrench. Bearings are cheap and easy to install. Use any kind of a Mickey Mouse setup you can think of to pull the flywheel. Mercury Marine don't know chit about that sort of thing. They just like to sell tools. Besides, flywheels, stators, and crankshafts are cheap and easy to install.

My 02
John

 

[walleye1968]

Re: Getting flywheel off

i have 2001 40hp and the nut is a15/16 start there

 

[Gary H NC]

Re: Getting flywheel off

i have 2001 40hp and the nut is a15/16 start there

That looks about right...will start there. Wasn't sure if it was metric.Thanks!

So J_martin,are you saying an impact will kill the bearing or stator?
The boat is on a lift with no trailer so i thought the impact would be helpful in getting it off.I will try it by hand first then....

 

[green4themoney]

Re: Getting flywheel off

why not invest in a universal flywheel puller cost about 20 dollars and saves you from screwing anything up?

 

[j_martin]

Re: Getting flywheel off

An impact wrench is basically a rotary hammer. Would you go at a precision roller bearing with a hammer?

The easiest thing to do is hold the flywheel with a soft strap wrench and use a ratchet, or strong arm to remove the nut.

The proper puller threads into the center hub of the flywheel. It is by far the easiest and safest way to remove it. It comes with a protector for the end of the crank shaft, and doesn't require removing any of the flex plate bolts. Don't use an impact on that device either.]

hope it helps
John

 

[Gary H NC]

Re: Getting flywheel off

Thanks for the help guys. Will not use the impact..

 

[donrjuan]

Re: Getting flywheel off

why not invest in a universal flywheel puller cost about 20 dollars and saves you from screwing anything up?

Agreed. I use the same and it works like a charm

 

[Gary H NC]

Re: Getting flywheel off

Harbor freight or Northern tool will get checked in the AM..
I could use a universal puller anyway. Worth a try before buying the 80 dollar Merc tool..

 

[lowkee]

Re: Getting flywheel off

Hmm, I've never not used an impact gun to remove or install a flywheel. I'm sure there is a ft/lb torque for the nut, but I wouldn't ever want the liability of a flywheel whipping off because I hand tightened that nut. The flywheel would shred everything under the cowling.

As for removal, since the crankshaft is so thick, either way works fine, hand or impact. For smaller high torque bolts I always use the impact, since it greatly lessens the likelihood of breaking the bolt. Call me spoiled, but some tools I wouldn't work without, and my impact is one of them.

As for flywheel nuts, 7/8 and 15/16 are almost the universal sizes. I have seen some 1" and 1 1/8" but not often. I don't recall if even honda's use a metric nut. At that size, you could likely get by with a SAE in a pinch, anyhow.

I bought my universal puller at HF for about $14, I believe. Works as it should. Doesn't handle steering wheels, tho

 

[Gary H NC]

Re: Getting flywheel off

Thanks Lowkee,
I think i will go the universal route first...

 

[sschefer]

Re: Getting flywheel off

J_Martin, you sarcasim is absolutely appropriate - For the rest of you that don't get it, here's why -

1. The first reason: The manuals all tell you to either buy the special flywheel holding tool or use a modified strap wrench to hold the flywheel and then use a breaker bar and cheater (short lenght of pipe) to remove the nut.

2. The second reason: The flywheel has magnets in it. The magnets may be screw on or glue on but in either case impacting the flywheel with any tool will most certainly cause them harm.

3. The third reason - When Merc say's you need a specialty tool to perform a specific job then get the tool. When it comes to pullers, some engines use a specialty tool that screws into the hole in the flywheel where you removed the nut from the crankshaft. If you use any other type of tool you will most likely damage the flywheel.

O.K. Now there is nothing that says you must buy the tool from Merc but it must perform that same basic function as the Merc. What you must remember is that this engine is not an old Iron Duke or bullet proof 350 Chevy. You have to be careful or you will break things and odds are when you do, the part will no longer be available.

If for some odd reason this sounds like the voice of experience it's becasue it is.

 

[Gary H NC]

Re: Getting flywheel off

I know all to well about breaking stuff using the wrong tools.Done that before.

I did find the Merc puller on Ebay for 49 bucks...I think i will buy it and add to my ever growing tool box...

 

[xltier]

Re: Getting flywheel off

I know all to well about breaking stuff using the wrong tools.Done that before.

I did find the Merc puller on Ebay for 49 bucks...I think i will buy it and add to my ever growing tool box...

i just bought one on ebay for 50.00 it does make things easy.

 

[JustJason]

Re: Getting flywheel off

Hey Gary... I dont know if this is 2 late but this is what I do. I use impacts all the time. My 18V Dewalt has taken off everything so far without much struggle. And honestly, and I'll get a whippin for this one. But unless the nut is completely trash I reuse them with a bit of blue loctite and just hammer them back on with the gun. If they are trash I get new ones and loctite the new ones. Your not going to hurt the stator or anything else. And if a magnet falls off it was going to fall off anyways. Not much you can do about that. Just CYA by saying that you can't inspect the magnets while the flywheel is on and the older an outboard gets the higher the chances of it having broken magnets goes up.

As far as pulling it. I have a Crapsman puller. It's worked okay but has busted on me twice over 10 years (warranteed of course) biggest thing is to use grade 8 bolts (can get them at depot) and thread them all the way in. If the flywheel wont come off just using the forcing screw (which I impact down as well) Tighten the forcing screw and use a punch to tap the top of the crank. It's Tighten, Tap, Repeat, and they will come off. They come of with a bit of a "snap" sometimes so don't let the noise startle you. Sometimes it will sound like something broke.

Dunno on the nut size... can you get in there with some veneers?

 

[Ware5150]

Re: Getting flywheel off

I have a trigger assembly and flywheel puller on the way. I got the puller for 27.99 at the site below. I have not seen a flywheel wrench. I have some strap wrenches but they are too short. I bought some nylon strap at Ace and am going to give this a shot.

If the flywheel is so hard to get off how easy does it go back on?

http://mbsmfg.com/mercury.html

 

[sschefer]

Re: Getting flywheel off

It goes back on easy, just use a little zinc based anti sieze compound on the crankshaft and it will be much easier to remove the next time. Your on the right track with the strap wrench, you have to make a new strap.

If your puller comes with a coarse thread bolt then tighten it until you feel like it should come off and gently tap the puller body with a ball peen hammer. If it doesn't pop off on the first try give the bolt another 1/4 turn and try again.

 

[wilde1j]

Re: Getting flywheel off

Crankshaft and flywheel bore must always be dry, with no oil or any other substance on them prior to reinstalling the flywheel. NEVER coat with anything, period!