How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson 20?

[joehudock]

I had what I thought was a leaky upper crankshaft seal on a 67 Johnson 20 hp. I split the crankcase and changed the seal.
Just tried the motor and it did what it did before, cuts out every so often, like 10 to 30 seconds apart. I think I see oil up around the magneto again after just a couple minutes of running.
I have not pulled the flywheel yet, since I will need to borrow back my puller for that. Would a worn bearing, or worse yet worn crankshaft cause this problem? I would change the bearing if that would do the trick but if the crankshaft is worn then I would just junk the motor.
The bearing and crankshaft did not look like other than shiny metal when I had things apart. The problem wasn't just the seal I guess. What should I look for on the crankshaft and bearing when I get the case split again? Or is there a way to determine if the bearing or crank is bad prior to splitting the crankcase?

 

[Daviet]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

Can you rock the flywheel from side to side?
I don't think your problem is a crank seal by the way you described it, sounds more like you are dropping a cylinder.

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

Can you rock the flywheel from side to side?
I don't think your problem is a crank seal by the way you described it, sounds more like you are dropping a cylinder.

I can move the fly wheel about .007 inches back and forth. I determined this by clamping my dial indicator base to the starter motor, the only thing magnetic on the motor big enough for the indicator base, and adjusting the dial indicator contact point to rest on the fly wheel. When I push and pull on the fly wheel total movement is 0.007 inches. What is "dropping a cylinder"? Doesn't sound good though. I really appreciate your help in figuring this out.

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

Can you rock the flywheel from side to side?
I don't think your problem is a crank seal by the way you described it, sounds more like you are dropping a cylinder.

I checked again with the indicator base on the flywheel with magnet holding to the big nut on top of the flywheel, this time I got about 0.003 inches of movement with indicator point on the outer rim of the magneto base.
Is there a "best" way to measure flywheel motion back and forth or is that no help in figuring out the problem?

 

[F_R]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

If you had the bearing in your hand, you should have seen if it was bad. A good bearing (and crankshaft) will look perfect. Any wear, rust, flat spots, etc means it is junk.

I don't think yours is bad at .003". In fact, a roller bearing must have "some" clearance. The service manuals don't even specify how much.

EDIT: By "perfect", I mean there will be evidence of where the rollers rolled. It is called "burnished". But it should be smooth, not undersized, and defect-free.

 

[Daviet]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

By dropping a cylinder I meant it sounds like you are loosing spark to a cylinder.
You can test it by using a timing light on each plug wire while it is acting up and see if you have a steady light or it skips when the ehgine acts up.

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

If you had the bearing in your hand, you should have seen if it was bad. A good bearing (and crankshaft) will look perfect. Any wear, rust, flat spots, etc means it is junk.

I don't think yours is bad at .003". In fact, a roller bearing must have "some" clearance. The service manuals don't even specify how much.

EDIT: By "perfect", I mean there will be evidence of where the rollers rolled. It is called "burnished". But it should be smooth, not undersized, and defect-free.

Well everything looked fine when it was apart as far as I could tell, but then I would not know what to look for. However I did bring the bearing with seal in it along with other stuff to the OMC dealer when I got a new O-ring and gaskets and some other stuff. The mechanic there saw the bearing and did comment that the seal was not seated uniformly all around. He didn't say anything about the bearing condition.
He did say that he had the special tool for fishing out the seal without breaking opening the crankcase. However, last fall when I called about doing that he was reluctant to do the job unless I brought in the motor whole so he could charge for doing the whole job, not just pulling the seal with the magic tool. Back then he did say that the magic tool for seal pulling doesn't work all the time. I can believe that part, because it took more effort than I thought it would to knock out the old seal.

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

By dropping a cylinder I meant it sounds like you are loosing spark to a cylinder.
You can test it by using a timing light on each plug wire while it is acting up and see if you have a steady light or it skips when the ehgine acts up.

I'm pretty sure its missing spark and I think the cause is oil/gas mix coming up through the upper crankshaft seal and getting sprayed on the points. Tomorrow I'll have the puller and get the flywheel off and see if there is oil in the magneto again. I think I can see an oil type smear on a portion of the side of the magneto plate when I look under the flywheel. It may be that the seal I put in was defective out of the box, although it looked new. But then I am speculating about another seal leak. Last fall the magneto definitely had lots of oil contamination. That's when I decided to change the seal. The shifter lock lever was also broken with the engine kicking, bucking and missing the way it did.
This spring with the replaced shifter lock lever it stayed in gear when it missed and bucked. I would bet money on a missing spark just because of the short duration on-off nature of the problem. My experience has been, at least with cars, that jerky rough running is an electrical problem while fuel or mechanical problems have longer time constants. I'll reply again tomorrow when I can get the fly wheel off.
In the meantime, does anybody know if a seal can go bad just laying around the bench and getting knocked on the floor? I've heard that front wheel drive shaft seals on car transmissions are very tender that way and will leak even if you look at them funny before they are installed in the car. I had the seal out of the package last fall and fussed with getting the old seal out without splitting the crankcase. Gave up when the weather got cold and just started in this spring as it got warm to disassemble the motor and open the crankcase to change the seal the long way.

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

By dropping a cylinder I meant it sounds like you are loosing spark to a cylinder.
You can test it by using a timing light on each plug wire while it is acting up and see if you have a steady light or it skips when the ehgine acts up.

I pulled the flywheel and as I expected there is oil there on the points and elsewhere on the armature plate and under it. So the question I have is there any other way for oil to get out of the crankcase besides through the crankshaft seal? Very little oil on the seal itself but there is some right around where the seal meets the crankshaft.

 

[Beek14]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

Well everything looked fine when it was apart as far as I could tell, but then I would not know what to look for. However I did bring the bearing with seal in it along with other stuff to the OMC dealer when I got a new O-ring and gaskets and some other stuff. The mechanic there saw the bearing and did comment that the seal was not seated uniformly all around. He didn't say anything about the bearing condition.
He did say that he had the special tool for fishing out the seal without breaking opening the crankcase. However, last fall when I called about doing that he was reluctant to do the job unless I brought in the motor whole so he could charge for doing the whole job, not just pulling the seal with the magic tool. Back then he did say that the magic tool for seal pulling doesn't work all the time. I can believe that part, because it took more effort than I thought it would to knock out the old seal.

I would think being that that mechanic had said the seal didn't fit uniformly around it, could mean that there is an imperfection in your bearing. Possibly causing the seal to leak..

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

I would think being that that mechanic had said the seal didn't fit uniformly around it, could mean that there is an imperfection in your bearing. Possibly causing the seal to leak..

Nope, he didn't say anything about the bearing, other than just that I needed to finish seating the seal all the way in uniformly all around. That I did do and checked with a depth gage before I put the motor back together.
From what I have determined so far is that the bearing itself is OK. The question remains, where is that oil coming from, out that seal I just put in or some other place near the top of the crankcase. Pulling the flywheel two days after running the motor for 3 minutes there was a little oil where the seal meets crankshaft, could be the rest got flung out? A lot more oil on non-spinning parts like armature plate, magneto base, wires and points. Or is there another place the oil could come from?

 

[Daviet]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

I can't think of any place else that oil could come from. The only oil in the system is mixed with the gas, and the upper crank seal is the only thing that keeps the oil/gas mixture from escaping.

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

I can't think of any place else that oil could come from. The only oil in the system is mixed with the gas, and the upper crank seal is the only thing that keeps the oil/gas mixture from escaping.

Thank you for taking the time to think about this and respond. I had thought there might be some other way for the oil to get there since I just changed the seal. But this was the first time I ever worked on the power head and was not sure at all. The seal must have somehow been damaged in the 6 months or so I had it laying around before getting it installed. Well, at least the second time around should not take anywhere near as long as the first time.

 

[Daviet]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

You might want to think about trying to find the tool that you can use to pull the seal without taking down the engine, might be the cheaper way to go.

 

[joehudock]

Re: How do I determine if crankshaft bearings as well as seals are bad on 67 Johnson

You might want to think about trying to find the tool that you can use to pull the seal without taking down the engine, might be the cheaper way to go.

That it would normally be, but the only place around here with the tool wanted a minimum of 2 hours shop labor and would not guarantee that it could be done without splitting the crankcase. My guess is they really didn't want to work on it. That's why I changed it the long way myself. The other two places that worked on Evinrudes and Johnsons didn't admit to having the special seal puller. Since I don't pay for my time its cheaper to do it by splitting the crankcase. Hopefully, changing the seal again will fix the oil on the points problem.