Black scuff marks on cylinder walls

[mertkajosh]

Use a factory replacement gasket.---Best quality

Are these opening suppose to be in the crankcase heas assembly?

 

[mertkajosh]

Use a factory replacement gasket.---Best quality

I have a question about the oring that sits at the top of the driveshaft. Mine currently doesn’t have one on it. When I replaced the water pump last year it also didn’t have one when I pulled the lower unit. My manual says to install oring on the upper drive shaft but I can’t find an oring on any diagram for my engine. So I’m confused about whether or not I need an oring on the drive shaft. Could you possibly help me answer that? And if so, would you happen to know the part number if I do need that gasket? Thanks again!

 

[mertkajosh]

I have a question about the oring that sits at the top of the driveshaft. Mine currently doesn’t have one on it. When I replaced the water pump last year it also didn’t have one when I pulled the lower unit. My manual says to install oring on the upper drive shaft but I can’t find an oring on any diagram for my engine. So I’m confused about whether or not I need an oring on the drive shaft. Could you possibly help me answer that? And if so, would you happen to know the part number if I do need that gasket? Thanks again!

There is definitely a spot for one on the driveshaft. But there’s also a big oring inside the crankshaft head cover. So does that seal the driveshaft or does it need an oring added on the driveshaft as well?

 

[jimmbo]

It does look like the Bottom Crankcase Seal has seen better Days.
However, knowing which engine this is, will make it easy to find the correct Parts Listing, which will reveal if it has an O-ring on the Driveshaft.

 

[mertkajosh]

It does look like the Bottom Crankcase Seal has seen better Days.
However, knowing which engine this is, will make it easy to find the correct Parts Listing, which will reveal if it has an O-ring on the Driveshaft.

It’s a 1994 Johnson 90hp v4. Model number J90TLERC. I have looked at multiple diagrams and cannot seem to figure out if it’s suppose to have an oring below the splines.

I am replacing the bottom crankcase seal and the oring that sits inside the sleep that goes at the end of crankshaft that sits under the crankshaft head

 

[jimmbo]

Looking at the Parts Diagram for that Model # doesn't show an O-ring on the Driveshaft.
Put some Grease on the Splines, but make sure there is None on the Top of the Driveshaft, or Bad Things will happen. Do Not put any grease on the Splines in the Crankshaft, as that too can cause Bad Things. Wash them out with Brake Clean

 

[mertkajosh]

Looking at the Parts Diagram for that Model # doesn't show an O-ring on the Driveshaft.
Put some Grease on the Splines, but make sure there is None on the Top of the Driveshaft, or Bad Things will happen. Do Not put any grease on the Splines in the Crankshaft, as that too can cause Bad Things. Wash them out with Brake Clean

Thank you so much!

 

[jimmbo]

Going back in the yrs, it appears that 1991 was the last yr there was an O-ring at the top of the Driveshaft.
There would be an O-ring included in the Water Pump Kit, if the Kit was covering a large number of years.

 

[mertkajosh]

Going back in the yrs, it appears that 1991 was the last yr there was an O-ring at the top of the Driveshaft.
There would be an O-ring included in the Water Pump Kit, if the Kit was covering a large number of years.

So I’m assuming the big thick black one inside the crankshaft head seal is what stops water from from back up into the motor and keep oil from leaking out. That and the seal

 

[jimmbo]

Deleted

 

[mertkajosh]

Going back in the yrs, it appears that 1991 was the last yr there was an O-ring at the top of the Driveshaft.
There would be an O-ring included in the Water Pump Kit, if the Kit was covering a large number of years.

Do you know what these little pin holes are? Looks like corrosion or something. The pits aren’t too deep but there’s quite a few of them

 

[racerone]

???----Don't worry about those pin holes !

 

[mertkajosh]

???----Don't worry about those pin holes !

Ok it scared me when I saw them. There’s quite a few in almost all the ports. Just wanted to make sure it’s all good. Thanks!

 

[Mc Tool]

They are bubbles in the ally casting that have been exposed by the machining and as said above dont worry about them ............and dont think about all the big ones you cant see

 

[jimmbo]

Just Bubbles in the Aluminium

 

[racerone]

Little bubbles are not troubles ----On these wonderfully simple motors.

 

[mertkajosh]

Little bubbles are not troubles ----On these wonderfully simple motors.

I just figured since it was on the hot side of the piston the heat caused those pin holes. Thanks for the help and information!

 

[jimmbo]

Heat can cause Cracks, but those Bubbles were formed when the Aluminium was Molten

 

[mertkajosh]

Heat can cause Cracks, but those Bubbles were formed when the Aluminium was Molten

Good to know. It scared the crap out of me. I really do appreciate everyone’s advice and input. It’s helped me tremendously while working on this motor. Thanks again!

 

[Mc Tool]

yeah well dont look at nothing else aye ....just put it back together and go boating ,