"Walking" Flywheel...

[Big Jay]

Re: "Walking" Flywheel...

The flywheel looks original, and looks the same as any I can find in pics of the same motor online...

 

[bwkre]

Re: "Walking" Flywheel...

If you place the flywheel on the crank and seat it to the bottom, no nut, you should not be able to wobble it. It should be snug. Have you had the timing cam off? As far as I know it should sit on the crankshaft shoulder, no shims or spacers under it. If all else fails, I would have someone else confirm that there is or is not any damage.

 

[Chinewalker]

Re: "Walking" Flywheel...

If you remove the key and put the flywheel on, does it wobble? That would indicate as to whether it is hanging up on the key or if there's an issue with the tapers...

 

[Big Jay]

Re: "Walking" Flywheel...

If you remove the key and put the flywheel on, does it wobble? That would indicate as to whether it is hanging up on the key or if there's an issue with the tapers...

I have just torqued it down, but am thinking of pulling it again to check. Good idea pulling the key to see...

 

[the machinist]

Re: "Walking" Flywheel...

I have seen one that was probably a used replacement off a differwent motor, (or could have been spun) that the top of the flywheel taper had a slight ridge that would bottom out on the top of the shaft taper. If that is the case, just use a 1/2 round file & remove that ridge so it will settle down onto the taper.

 

[Big Jay]

Re: "Walking" Flywheel...

I have seen one that was probably a used replacement off a differwent motor, (or could have been spun) that the top of the flywheel taper had a slight ridge that would bottom out on the top of the shaft taper. If that is the case, just use a 1/2 round file & remove that ridge so it will settle down onto the taper.

Thank you so much... if you are the author of Lerroys Ramblings, thank you again lol. You helped me on a different motor in the past.

I will look at the taper and see if this is the case and post my findings....

 

[bwkre]

Re: "Walking" Flywheel...

I've been following this thread with interest! So Big Jay what did you find?

 

[Big Jay]

Re: "Walking" Flywheel...

Hey bwkre...

Well... it just seems like I'm gonna wind up overhauling this engine yet (kidding).

On closer inspection, I do have some sort of build up on the crankshaft taper. It looks to me like the flywheel had been on so long that it actually fused itself to the shaft, and once it was removed it left 3 round spots of itself still fused to the shaft. Of course it won't ever sit the way it was again so I'll file it down.

I've been using the manual at boatinfo.no and read that if there is any oil whatsoever present on the armature plate, the top seal must be replaced. So of course I looked.... and of course there is oil present:facepalm:. So... now I trying to figure out how to remove the points cam to access the seal.

The manual says to work it up and out, but it looks like it is all one piece with the crankshaft on this model.

And while I had the armature plate off I decided to inspect the coils a little closer and it turns out the laminates on one are separated and there is a small hole in the casing. So I have to replace it too, and if I replace one I might as well buy two.

So my new question is this:

How do I access the top crankshaft seal to replace it?

 

[tx1961whaler]

Re: "Walking" Flywheel...

I wouldn't replace that seal quite yet. Take the magneto plate off, clean up the plate and seal area, and then run it for awhile. If after that you see signs of leakage, then replace the seal.

 

[Big Jay]

Re: "Walking" Flywheel...

Ok... lol I won't argue with you haha!

I don't want to change it if I don't have to.

Here are some pic's of where I'm at right now:

I had already cleaned up the shaft area, wish I hadn't because you can't see the greasy oil build up that was there.
You can also see a spot where the flywheel left some sort of deposit on the crankshaft taper... there is 2 or 3 more like this one as you feel around the diameter.

 

[Big Jay]

Re: "Walking" Flywheel...

Here is some of the grease that was under the armature plate:

 

[bwkre]

Re: "Walking" Flywheel...

Hey Big Jay,

Glad to see your still working on it. Those marks on the taper are probably the wobble problem. Your repair method should take care of it. I had a look at the parts breakdown on another site and it appears that the timing cam is part of the crank. It was not shown, was not in the parts list and from closer inspection of your picture it appears to be machined on the crank. The oblong section is right below the taper, correct?
I know my 76 9.9hp and 61 18hp both have removable cams and they both engage the key on the tapered shaft. The key on yours is up high on the taper, so, if the cam is removable the would have to be a second key to keep it in place?

I also agree with cleaning and running before replacing the upper seal. You will probably find it wasn't leaking.

 

[oldman570]

Re: "Walking" Flywheel...

The grease on the bottom of the armiture plate has to be there as the plate moves on the top of the motor and needs something to lube it. As long as the compresston is good the upper seal is not that bad yet. When the motor gets warmed up that grease will get thin and run somewhat and that is probly what you are seeing. Fileing the high spots only should let the flywheel set back down as it should. Good choice in rebuilding the whole mag as it is best as long as you have it apart and will save time later. From the way the key for the flywheel looks ether you have another key for the cam or the cam is ground on the crankshaft. Heating it up to try removing will ruin the upper seal. There is a probuct called Fresse Off that can be bought at a local auto parts store that can be used on the cam to see if it can be removed. JMO
Oldman570

 

[Big Jay]

Re: "Walking" Flywheel...

Alright, I'm just going to replace the coils, re-grease and reassemble and keep an eye on the top seal. I have good compression on both cylinders (120/119) so I won't worry yet.
I also have new points and condensers too, figure it couldn't hurt.

But what type of grease should I be using under the magneto?

Also, I notice that the available parts lists for most sites including BRP only date back as far as 1968, does that mean that by next year they'll only carry back to 1969?

 

[HighTrim]

Re: "Walking" Flywheel...

You can see your parts list at marineengine.com, they go back to '55

Not too much grease under the mag plate, or youll ruin your points.

 

[Big Jay]

Re: "Walking" Flywheel...

You can see your parts list at marineengine.com, they go back to '55

Not too much grease under the mag plate, or youll ruin your points.

Thanks HighTrim, but what type of grease? Plain Bearing grease?

 

[Big Jay]

Re: "Walking" Flywheel...

Success !!

Well, sort of lol. I finally started this motor tonight, albeit in a barrel mind you... but it ran !!!!

So happy right now


I managed to file the taper smooth and get the flywheel to sit relatively flat with next to no wobble, and after confirming my spark jumped a 1/4 " on the tester... I figured it was time. I replaced the fuel lines on the powerhead and went on to dig a 6" hole to set my barrel in to accommodate the long shaft and had the wife hold tight while I reefed. I never realized how good a crank this 40hp needs to turn over, I guess it's called a BigTwin for a reason! My arm won't be sore tomorrow, but it'll be almost sore lol. 5 pulls and she kicked, 6th she was running smooth.

I did notice however the impeller was weak once the thermostat opened. Not much water but a little flowing. So I didn't run it long, but it sure sounded sweet.

Now I have to endure waiting 'til spring to bring the old Traveller boat I'm mounting it on back to life and get her out on the water in order to really test it out

Thanks a lot for the guidance guys, this site has been a great help to a musician in need .

 

[Rick.]

Re: "Walking" Flywheel...

You've made good progress. Be proud. Rick.