Crank bearing???

[AU10]

1988 Johnson 140 V4 looper

I was out running the other day, and all the sudden lots of engine noise (sounded like somebody picked it up and shook it) so i throttled down quickly and shut it off. Just did a compression check, 110 on all 4... When turning the flywheel in gear and in neutral, it has a rough spot that is tough to turn. Would this be the crank bearings? How tough/expensive of a fix is this? As you can probably tell, I don't know a ton about outboards or engines at all.

Also, what would've caused this issue? I know it wasn't running hot or lack of oil in fuel...

Thanks in advance for any help/advice!

 

[jbjennings]

Re: Crank bearing???

You may have lost a magnet in the flywheel. I'd remove the lower unit and if the bad spot is still there, I'd remove the flywheel. IF all the magnets are there, then research other possibilties. Could be a bearing but I'd say it's not likely if you've had oil in the fuel.
JBJ

1988 Johnson 140 V4 looper

I was out running the other day, and all the sudden lots of engine noise (sounded like somebody picked it up and shook it) so i throttled down quickly and shut it off. Just did a compression check, 110 on all 4... When turning the flywheel in gear and in neutral, it has a rough spot that is tough to turn. Would this be the crank bearings? How tough/expensive of a fix is this? As you can probably tell, I don't know a ton about outboards or engines at all.

Also, what would've caused this issue? I know it wasn't running hot or lack of oil in fuel...

Thanks in advance for any help/advice!

 

[multimech]

Re: Crank bearing???

Could be the lower unit. Pull the drain plug and look at the oil. If you see a lot of metal in it, pull the lower unit and try turning the flywheel. If it turns easy, it is the gearcase. The gears are always driven. If you have a broken tooth or teeth it will make the sound you are talking about and the noise.

 

[AU10]

Re: Crank bearing???

Could be the lower unit. Pull the drain plug and look at the oil. If you see a lot of metal in it, pull the lower unit and try turning the flywheel. If it turns easy, it is the gearcase. The gears are always driven. If you have a broken tooth or teeth it will make the sound you are talking about and the noise.

So the gears in the lower unit are always engaged??? I always thought they were only when the motor was in gear... Well, that gives me hope! It's not too difficult to remove it is it?

If that is the case, how would I test a craigs list buy? Just turn the drive shaft and see if it spins freely?

 

[AU10]

Re: Crank bearing???

You may have lost a magnet in the flywheel. I'd remove the lower unit and if the bad spot is still there, I'd remove the flywheel. IF all the magnets are there, then research other possibilties. Could be a bearing but I'd say it's not likely if you've had oil in the fuel.
JBJ

THanks for the advice! I'll be pulling the lower unit tomorrow after work

 

[multimech]

Re: Crank bearing???

Yes, the gears are always driven, they are engaged to the propshaft by the clutch dog. If you have a tight spot, it could be a broken tooth or teeth that are contacting each other as the engine rotates.

 

[AU10]

Re: Crank bearing???

That makes sense because the tight spot is sometimes really tight and sometimes not very noticeable whereas if it were in the powerhead, it would be the same every time I would think. Thanks again for your help