Topic: mower flywheel removal

[stresssolutions]

older briggs and stratton 3.5hp vertical shaft.  I want/need to remove the flywheel to get at the points/condenser.  Seems like it is time to tune it up a little.

How does that sucker come off?  Or....what sort of puller works to take it off?  I've squirted the shaft and tapped it a bit, but....the holes that are arrowed at have no threads, or it'd be pretty easy to build a puller.  will try heating the area around the shaft to see if that'll pop it loose.

Any tips tricks concerns don't-do's?  thanks!

[martino1972]

mostly a healthy wack to the side of the flywheel makes it to come off....you do have the recoil part off I asume..
what also works well,is if you have an air chissel ,to put a pry bar under the flywheel,putting a little bit of pressure on it,pulling it up,then "air chissel" on the centre of the shaft....
they are not that tight on there,I mostly give it a good wack on the side of the flywheel....

[martino1972]

here you go......2 minutes into the video........

btw,this is from dave's farm...check him out on youtube....906 videos,all sorts of red neck,boys and their toys stuff....

[fuzzybutt]

i ended up using a harmonic balancer puller on my 5hp briggs

[kirkn]

Yep, what the video shows...

OR

For a vertical shaft motor, all you need to do is hoist up a bit on the flywheel (as if you were lifting the whole mower) and give a whack on the end of the shaft.  Pops right off.

The only thing, once or twice, I've had one that was really stubborn, and I wound up just barely mushrooming the end of the shaft to the point where the recoil thing wouldn't slide on.  However, 10 seconds with an ordinary flat file took care of it and I was good to go.

[Steve F]

Loosen the nut, lift up on the flywheel to support MOST of the engine weight, and tap on the NUT (not the crankshaft directly) and it should pop loose.  Be sure you check that the key isn't sheared or partially sheared.  Clean the crank taper really good before you reinstall the flywheel.  A wheel puller is available from Briggs, and is nothing more than a bolt in the center of a cast iron diamond shaped body, and two self tapping bolts at the ends that thread into the holes in the flywheel.
I don't recommend smacking the flywheel from the side.

[fuzzybutt]

be real careful if you end up having to pry against the flywheel, i've seen the things crack and break when the pulling forces were uneven

[Jonesy]

Briggs makes a puller for the job, however it's easy to make your own. It's just a small piece of bar stock with a hole in the center for the starter clutch spindle. On either side, there are smaller holes for two long self-tapping screws. These tap into the holes on the flywheel with the arrows, and then there are nuts on the screws to allow you to tighten them down and pop off the flywheel.

You can also gently pry up on the flywheel and smack the crankshaft with a brass or lead hammer, however do this with care....

You don't want to smack the flywheel directly, as you could cause it to shatter during operation. Also, if you sprayed penetrating oil on the crank, make sure you thoroughly clean the shaft and flywheel bore before reassembly. The flywheel fits to the shaft with a tapered joint and if it has any kind of lubricant on it there is a chance of it spreading while being tightened down, causing the flywheel to crack.

[stresssolutions]

Thanks, guys.  I made a tool, used big sheetmetal screws, instead of self tapping bolts, put some pressure on the flywheel, then tapped on it with my brass hammer, it popped loose. 

The reason for this tune up:  When my wife mows, she runs the engine full throttle and walks slower, the engine gets a little hotter than when I mow, and when she's about done, it 'lopes'.  RPMs run up and down, frustrating her.  vent holes in gas cap are clear, so I thought: condenser.  We'll see.

[martino1972]

lopes sounds more like a fuel mixer problem.....

[333]

Mix issue.  sounds like it's running rich.

Loosen the nut, lift up on the flywheel to support MOST of the engine weight, and tap on the NUT (not the crankshaft directly)

Never do it this way.  No matter how softly you hit the nut, you will F the threads.  If you are smacking the shaft, you will have to hit it real hard to mushroom the shaft.

[Steve F]

Mix issue.  sounds like it's running rich.

Loosen the nut, lift up on the flywheel to support MOST of the engine weight, and tap on the NUT (not the crankshaft directly)

Never do it this way.  No matter how softly you hit the nut, you will F the threads.  If you are smacking the shaft, you will have to hit it real hard to mushroom the shaft.

I used to do repair work in a Briggs authorized repair shop, and I said "loosen the nut", which means just no more than 1/2 turn, and hitting the nut, which is exactly to prevent damaging the threads on the crank.  If the nut does (never happened) get damaged, they're cheaper than a new crank.  Personally, I'd rather use the puller, but it wasn't likely that the original poster would have one of these.  The important thing is to never strike the flywheel.

[Steve F]

Thanks, guys.  I made a tool, used big sheetmetal screws, instead of self tapping bolts, put some pressure on the flywheel, then tapped on it with my brass hammer, it popped loose. 

The reason for this tune up:  When my wife mows, she runs the engine full throttle and walks slower, the engine gets a little hotter than when I mow, and when she's about done, it 'lopes'.  RPMs run up and down, frustrating her.  vent holes in gas cap are clear, so I thought: condenser.  We'll see.

"loping" is usually from a slightly lean condition, which is caused by an obstructed idle jet, or a vacuum leak, or a mixture adjustment.

[stresssolutions]

"loping" is usually from a slightly lean condition, which is caused by an obstructed idle jet, or a vacuum leak, or a mixture adjustment.
[/quote]  I wonder if it is as simple as refilling the tank when that starts???

The points were pretty good, but the 2 parts didn't mate very well, so I put a shim under the round cylinder part to raise it up a bit to match the other part.  thanks again!

[Jonesy]

The (more or less) official term for that is "hunting". It is indicative of a lean condition. I'm not sure how walking slower would have anything to do with it, as the engine isn't loaded as much as the slower travel allows the mower to cut the grass a little at a time and the blower on the flywheel is constantly providing cooling for the engine. Unless you have a really small lawn and the blower housing was packed with grass...

If you have the common "Pulsa-Jet" carb used on most Briggs mower engines in the days of breaker points, The jet can be removed by first removing the bolt containing the mixture screw. Under this is the metering jet, which can be removed with a flat-bladed screwdriver. To adjust the mixture, turn the mixture screw in until the engine runs unevenly. Then, back it out until the engine starts to falter. Turn the screw back in to the halfway point between the "too lean" and the "too rich" spots, slightly favoring a bit to the "too rich" side, as this will allow the engine to run best under load. The diaphragm might be faulty, not pumping enough fuel up to the carb. This diaphragm also serves as the gasket between the tank and carburetor. The fuel pump spring could be tired out as well.

A faulty condenser will usually cause the engine to miss.

Did you use OEM Briggs parts? I wouldn't be surprised if aftermarket points didn't line up very well, and they don't make as many of them as they used to... You could also buy a Magnetron conversion kit and never need points again.

[stresssolutions]

I am always impressed by the amount of knowledge that is available here.  Humbled, too.

I dunno about walking speed/engine speed...but I do know that it only happens on really hot days or when my wife takes extra time to mow.  and she only runs it wide open.

RE OEM Briggs.....the new key that I put in, from the kit, has the B&S logo stamped on it.  The kit was labled as B&S parts.  The old parts were not lined up well either, whatever. 

Thanks!

[scunny]

re the revs.........on my old B&S there is a wee paddle on the fly wheel that controls the engine speed, sort of a rev limiter, don't ignore this or you will find these engines dunna likey over revving, don't ask how I know 

[Jonesy]

Scunny-

RE the governor, did your connecting rod decide it needed some fresh air? 

Good point, though.. make sure the governor linkage works freely. We had an old generator that would sit for long periods of time. The throttle shaft would get sticky and if you didn't twist it back and forth a few times before you started it, it would race like a banshee!

[stresssolutions]

Yeah.  More dumb mower questions. OR, if you prefer, more mower dumb questions.

After electrical part replacement, which was pretty much an exercise, as predicted by most posters here, the mower ran well for 2 mowings, started fine for the 3rd, but only ran about 5 minutes. 

Does a mower engine that is running and running correctly blow air into the gas tank?  I ask, because mine does.  I was sitting there, looking at it, trying to imagine what the problem could be....as I have removed the needle valve screw thing and blew air thru it.  I took the carb off the tank and all is pretty clean.  So I pull the rope.  The air cleaner is off, the tank is full, and gas shoots up out of the carb.  I put my hand over the big hole on the carb, and pull the rope.  I can feel air coming out of the lid vents, and feel the pressure/suction as it goes around. 

I pulled off the little valve cover, they are both operating, I suppose one could be burned.

It does not start, and has an odd wheezing sound as it stops revolving after I yank the rope.

Which is the fuel pump spring?  the long small one, or the short one that has the cap on it?

Any ideas or suggestions welcome.  thanks