Briggs and Stratton flywheel nut removal

[benson1980]

Which is why the make the idiot proof tool in the first place.
Professionals use air guns or high speed battery impacts which only need hand pressure to hold the flywheel
After that it is a prybar or two and a hammer
I use a 3 leg puller with an air gun that will pop nearly every flywheel and you can hold the flywheel still enough with your fingers
Special tool that are made in very low volume and sold in even lower numbers will be very expensive because of the logistical / storeage costs if nothing else.
A pallet sitting on a shelf in a warehouse costs money, a lot more money than most would believe , the pallet space itself costs money every day of the week , regardless of how many times it is accessed then there is a picking cost a despatch cost and a retail profit .
Before it is made there is a design cost, a testing cost , and an inventory listing cost .
Then there is the profits in using it.
If it saves me 5 minutes 12 times a day it has made me a $ 76 profit.
If it does the same for the shops in town that blows out to a $ 150 profit
If it saves Joe Stupid the cost of a new fan that they broke getting the flywheel off then again it pays for itself very quickly .

IF no one was allowed to make profits then we would still be cutting grass with sythes & sickles .

No massive issue with expensive tools. I do have a problem with expensive tools that come with instructions that make absolutely no sense and the only logical answer I get as to how to use it comes from an internet forum rather than the people who make it, or not at least to Joe Stupids like me.

 

[Blockhead22]

Maybe I’m not understanding what the problem was but, all I did was secure the blade from moving (wedged a log underneath the mower) and taking the flywheel nut off was a breeze.
Getting the flywheel itself off has been an ordeal, yet to be finished.

 

[benson1980]

Maybe I’m not understanding what the problem was but, all I did was secure the blade from moving (wedged a log underneath the mower) and taking the flywheel nut off was a breeze.
Getting the flywheel itself off has been an ordeal, yet to be finished.

That is another way of doing it. But, for whatever reason my blade was spinning on the shaft (nut fully tightened), which was going to be the next thing I had a look at.

 

[Blockhead22]

Hi both- thanks again for your help with this problem. Managed to remove the flywheel nut using the above method, with that metal plate tool and putting a breaker bar through the square hole. Needed another pair of hands. Completely useless instructions from Briggs and Stratton and their tech support don’t reply either….

also used the pry method as advised, as again there’s no way the tool and following the instructions were going to get it off.

Bad news is flywheel key was actually fine. I’ve already serviced it, put fresh oil and petrol in, and cleaned the carburettor so at a bit of a dead end trying to fix it. I can just about get it started when cold but trying to start it again when warm is really difficult, and the starter rope will jerk back. Ended up buying a new Honda mower so will hopefully have some more success with that.

Congrats on the new mower, love getting new toys!
Next time you have the same issues you were having with the Makita, consider checking valve clearances before you write it off. Flywheel key is a good guess but out of whack valves can wreak havoc…

 

[benson1980]

Congrats on the new mower, love getting new toys!
Next time you have the same issues you were having with the Makita, consider checking valve clearances before you write it off. Flywheel key is a good guess but out of whack valves can wreak havoc…

Thanks! I suspect I have a few issues. I did manage to get it started today but the dipstick keeps getting forced loose somehow- excess pressure from somewhere? I definitely tighten it properly. It was also vibrating more than usual, then there’s the blade issue. I’ll put it in the garage and might have another tinker with it when I have time. I don’t mind taking things apart and trying to fix them and will have a look at valve clearances as well.

 

[sgkent]

IF no one was allowed to make profits then we would still be cutting grass with sythes & sickles

better get the blades sharpened - with the coming mandates to EV trucks and farm equipment we will be using them again unless we can harness lightning.

 

[SeniorCitizen]

A 2X4 two ft. long makes a excellent impacter when it smacks the end of the box wrench that's on the nut .

 

[Fish]

The cord jerking will happen if there is no blade, or the blade is loose.

 

[Cajun power]

Hi all,

I am attempting a repair on my Makita lawnmower which has a B+S 675Exi engine. I believe that the flywheel key is the culprit for difficult starting/rough running and therefore have taken it apart to access it.

I have bought the special (and very expensive) tool that supposedly both acts as the flywheel puller, and holds it in place to remove the bolt. I have tried the strap wrench method and as you can see this has just caused the fins to shear off as I tightened around them. I have therefore bought a replacement secondhand flywheel off Ebay. This repair is not going well...

Now that I thought I had the right tools, I cannot for the life of me work out how the tool works to hold the flywheel securely in place whilst I remove the nut. The bolts just drop down loosely into the two holes. They don't actually secure into anything underneath. The instructions say hold the bolt in place with a wrench, but I'm just holding onto a loose bolt!

Is anyone able to tell me what I'm missing, or best way of holding the flywheel in place? My other issue appears to be that my blade rotates around the spindle freely so I can't jam it from underneath. Was going to try and fix that after I've sorted this problem.

Thanks

just curious to ask: what made you think the keyway/woodruff was the problem with timing?

while it can happen, it's actually quite rare to see a keyway fail and slip.

there are a few things you can do to diagnose a slipped or sloppy keyway.

lock the flywheel down (anchor the blades so they never move)...the try and move the flywheel...if it slips back and forth...yup...that's your problem...

but sometimes a flywheel keyway is smashed and the doesn't actually move...it's just OFF in timing.

so then to do a better way to diagnose is to perform a timing light test. There are some youtube videos that explain how this is done. What you need to know before doing a timing light test, is where the ignition timing phase begins on your particular machine...paint or mark on the flywheel where that specific spot should happen. Like for instance on my kawasaki v twin (FR 691V, a very common mower engine), the magnet on the flywheel will be just right before it lands on the leading arm of the coil. One can prove this by moving the flywheel to top dead center for that cylinder..and to the other if you have a twin cylinder.. It's an easy concept and process to determine where ignition timing should occur. But you will need to consult with the specs on your specific engine to find out where that ignition timing mark SHOULD BE> if the woodruff key has smashed or slammed the timing will be off...so you have to know where the timing SHOULD BE PER SPEC. Then make that painted mark and go about shooting a timing light to it off the coil high tension wire. IF the timing mark is not correct, then yes, the flywheel is probably off. Some other symptoms when shooting a timing light is that the mark seems to vary back and forth...this would also indicate the keyway has smashed or slammed and that under load the flywheel is shifting back and forth under load. (this is particularly a thing with multi cylinder engines...where ignition pressure in one cylinder will overcome another weaker 4 stroke cycle in the other cylinder and this creates torque on a weak or damaged keyway..thus the flywheel moves...and the timing marks also moves with the timing light test.

a timing light is a very useful tool...especially in these small engines where timing is fixed and not variable, versus something more complex like variable timing or electronic timing/ignition. The vast major or mower engines are fixed timing systems....So this makes timing light test very easy to accomplish. Kind of like using a compression test set and a leak down test set, you can really get a pretty good idea about the condition of the engine overall by shooting a timing light. Brand new, most engines will shoot a really consistent steady mark on both cylinders...and it that timing mark should be exactly where the specifications indicate OEM in the area where the magnet approaches and meets the leading arm of the coil.

so a timing light might be a better idea to diagnose if you really have a flywheel keyway problem. It would save alot of time and frustration versus pulling the flywheel. It's just not that common a problem.

which raises the next question: since you know it's not the keyway...what is the root cause of the poor performance ? Have you determined what the problem is? just curious

 

[benson1980]

just curious to ask: what made you think the keyway/woodruff was the problem with timing?

while it can happen, it's actually quite rare to see a keyway fail and slip.

there are a few things you can do to diagnose a slipped or sloppy keyway.

lock the flywheel down (anchor the blades so they never move)...the try and move the flywheel...if it slips back and forth...yup...that's your problem...

but sometimes a flywheel keyway is smashed and the doesn't actually move...it's just OFF in timing.

so then to do a better way to diagnose is to perform a timing light test. There are some youtube videos that explain how this is done. What you need to know before doing a timing light test, is where the ignition timing phase begins on your particular machine...paint or mark on the flywheel where that specific spot should happen. Like for instance on my kawasaki v twin (FR 691V, a very common mower engine), the magnet on the flywheel will be just right before it lands on the leading arm of the coil. One can prove this by moving the flywheel to top dead center for that cylinder..and to the other if you have a twin cylinder.. It's an easy concept and process to determine where ignition timing should occur. But you will need to consult with the specs on your specific engine to find out where that ignition timing mark SHOULD BE> if the woodruff key has smashed or slammed the timing will be off...so you have to know where the timing SHOULD BE PER SPEC. Then make that painted mark and go about shooting a timing light to it off the coil high tension wire. IF the timing mark is not correct, then yes, the flywheel is probably off. Some other symptoms when shooting a timing light is that the mark seems to vary back and forth...this would also indicate the keyway has smashed or slammed and that under load the flywheel is shifting back and forth under load. (this is particularly a thing with multi cylinder engines...where ignition pressure in one cylinder will overcome another weaker 4 stroke cycle in the other cylinder and this creates torque on a weak or damaged keyway..thus the flywheel moves...and the timing marks also moves with the timing light test.

a timing light is a very useful tool...especially in these small engines where timing is fixed and not variable, versus something more complex like variable timing or electronic timing/ignition. The vast major or mower engines are fixed timing systems....So this makes timing light test very easy to accomplish. Kind of like using a compression test set and a leak down test set, you can really get a pretty good idea about the condition of the engine overall by shooting a timing light. Brand new, most engines will shoot a really consistent steady mark on both cylinders...and it that timing mark should be exactly where the specifications indicate OEM in the area where the magnet approaches and meets the leading arm of the coil.

so a timing light might be a better idea to diagnose if you really have a flywheel keyway problem. It would save alot of time and frustration versus pulling the flywheel. It's just not that common a problem.

which raises the next question: since you know it's not the keyway...what is the root cause of the poor performance ? Have you determined what the problem is? just curious

It was difficult to start and the cord was pulling back. Some Googling suggested the key was worth checking and I thought it would be easy to check! It was, apart from getting the nut off.

not sure as yet what is causing the performance problems, but to be honest aside from basic checks such as flywheel key, carburettor etc I’m a bit out of my depth. I can just about get it started and running so I will try and sort this loose mower blade.