What is the logic of banging DOWN on a crankshaft to remove a flywheel?

[Steve Barker]

BUT it is the first choice. And if you had a B&S manual, you'd see that.

[Tony]

Why don't you just admit that you were not able to do what thousands of other people do successfully quite often, and to make matters worse, you also broke something else in the process?

[Harry K]

Asking the same question here, and getting the same answers, isn't going to change anything.

To add something that hasn't been mentioned (or I didn't see it). The inertia delivered by the hammer affects the crankshaft, not the flywheel (you are preventing it from moving).

At the end of the day you will just have to accept the fact that it does work when done properly and won't cause damage to anything.

Harry K

[Harry K]

Why don't you just accept the _fact_ that it has worked when done properly since B&S engines were first built? That it is also done by almost every small engine mechanic that has ever worked on them? You have been given clear explanations on why it works, You are just being obstinate in refusing to believe them.

Harry K

[Harry K]

The 1/8" was a gross exageration. It is only a few thousandths but that is all that is needed. There is _no_ mechanical assemblage that does not have a bit of "play" in it.

Harry K

[Harry K]

Again, the one who said 1/8" misspoke. It is only a few thousandths.

Harry K

[Harry K]

:

So you "ham handed" your engine and now want to tell all the engine techs out that that have done it for about 100 years it doesn't work. See anything odd about that?

Harry K

[Harry K]

:

BTW if those holes were "designed to be tapped 1/4 x 20" they would have come from the factory that way.

Harry K

[Harry K]

And very repeatedly. That wall should be almost destroyed by now.

Harry K

[Harry K]

Back to your repeated "because I couldn't do it, everybody who has ever done (and continues to do) it is wrong, wrong, wrong" You have a lot of manuals that you need to start rewriting.

Harry K

[James H.]

Allow me to clarify. I didn't drill anything. All I did was tap the two pre-drilled holes in the flywheel. They are there, it turns out, expressly for the purpose of removing the flywheel.

Apparently the proper way to remove this type of Briggs and Stratton flywheel is NOT to bang down on the crankshaft while prying up; nor is it to lift up on the edges with a flywheel puller; but it is to lift up from near the center with the two bolts in those pre-drilled holes.

For some reason, Briggs and Stratton prefers us to tap the holes ourselves, which I did with a 1/4 x 20 tap. Once I did that, the flywheel lifted up easily with a harmonic balancer puller.

Point is not many people seem to know this so that's why the word needs to go out that the other methods are deprecated for this type of motor.

[James H.]

Hi Oren, I don't disagree with you on replacing the flywheel (I ordered one from Sears in fact, but didn't mention it because it wasn't relevant to the discussion).

However, please realize, that "tradition" is apparently dead wrong here.

This is tradition:

However, the owners manual begs to differ with tradition: The ONLY way to remove this type of Briggs & Stratton flywheel is to tap the pre-drilled holes and lift up with a two-bolt harmonic balancer puller, the lifting force being near the center of the flywheel and the indented tip of the crankshaft.

The "flywheel puller" is part #363 (Sears part number 19069, Briggs and Stratton part number BS 19069) on page 38 and 39 of the Owner's Manual for the Craftsman Rotary Lawn Motor, 6.5 Horsepower, 21" Rear Discharge, Model No., 917.388853 with the Briggs & Stratton 4-cycle engine, model number

123K02-0444-E1.

Here is the flywheel puller for $7.50 online:

It's sheer folly to try to bang the flywheel off with shock and awe.

[James H.]

Hi Bob, On the Briggs and Stratton web site, they explain the use of the flywheel puller.

In the owners manual, they show a picture and the part number for the flywheel puller.

While I definitely see "tradition" has it that almost everyone (except Sears and Briggs and Stratton) recommends banging on the flywheel, that's NOT the way to remove the flywheel on my Craftsman Briggs and Stratton engine! :)

This video shows the (wrong) traditional method:

This is the $7.50 flywheel puller (Briggs & Stratton P/N: BS 19069): The owners manual (page 38 & 39) show this as Sears P/N: 19069: Point is, banging on this type of Briggs & Stratton engine is sheer folly when there is a perfectly cheap and effective method.

Even the Briggs and Stratton web site says (at least for their racing engines) the ONLY way to remove a flywheel is to use a flywheel puller.

So, I'm just letting folks know the lessons learned. I asked. I got advice. Most of it was wrong. But some of it was dead on right. I made mistakes. I learned. I found out, the hard way, the right way. And I'm letting folks know.

The only thing that had confused me was how the old way was supposed to work (logically that is) ... and it turns out that it does work ... but it's the wrong method to use for these Briggs and Stratton engines.

I need to post some pictures instead of responding with text. :)

[James H.]

It IS designed for the flywheel puller and the holes are not tapped. We already pointed out this in the owners manual.

In addition, the Briggs & Stratton FAQ says to tap the holes with a 1/4 x

20 tap: This says it's dangerous (to the equipment) to smack the crankshaft. Read this: says the same thing.

This says to use the flywheel puller:

The more I learn about this, the more I realize the "traditional" shock and awe method is wrong (and dangerous to the equipment).

Yes, it works (for those of you with experience); but it's not the proper method of removing the flywheel on this type of engine.

I'll post some pics for you guys to see.

[James H.]

B&S says first choice is the flywheel puller:

[James H.]

Hi Harry, I appreciate your input. I can't say why the factory doesn't tap those holes, but, they have arrows and something like the words "tap here" on them and all the Briggs and Stratton instrucions say to tap them, so, it's pretty clear what to do (once you know the answer).

I suspect the reason they don't tap them ahead of time is pure cost; albeit it can't cost a lot.

See these references, all of which say to tap the holes when pulling the flywheel on a Briggs and Stratton engine:

etc.

[James H.]

So that makes three (somewhat similar) explanations so far:

1. Vibrations allow the friction to lesson
2. Move the crankshaft down 1/8th of an inch moves the flywheel up
3. Try to move the crankshaft down; it can't; so the flywheel moves up

[James H.]

I uploaded some pictures which show the Briggs & Stratton flywheel and even the instructions on the flywheel itself to tap the holes.

Direct Link:

Link: Player: It's pretty certain by now that the traditional shock and awe method works; it's just not the correct approach for this type of engine (according to Briggs and Stratton and Sears).

I ruined my flywheel and intake manifold trying that hammer & pry method, so, if you are going to use the brutish approach, it's best you use it on someone elses' engine. :)

Thanks for all the help. I learned a LOT about lawnmowers. I'll let you know when it's all back together (parts haven't arrived yet).

I realized I didn't have actual pictures of the flywheel being removed, so I'll re-enact them tomorrow in the daylight and add them.

[James H.]

By now, I'm convinced the shock and awe method of hammering and prying works, but I wouldn't recommend that method except on someone elses' mower! :)

Pictures here of my mower. I learned a LOT from you guys! Thanks! Direct Link:

Link: Player:

[Hustlin' Hank]

The "preferred method" is to use a puller because the risk of damaging other components is lessened. But, the "traditional method" also works well for those with experience.

The experienced mechanic will probably use the traditional method due to the TIME it takes. Time is money for the professionals. They can remove a flywheel in a couple minutes as compared to having to tap holes and use a puller which may take much longer.

I have used both methods on various engines. Most motorcycle engines use a totally different type of puller and MUST be used because of the weak metal surrounding the flywheel to pry on (replacing a motorcycle case gets expensive and time consuming.

On some of todays generators, the only way to get the armature off the engine is to use a hammer.

In closing, whatever works for ya! You can't argue with success.

Hank