1985 20 hp Johnson non electric start what are the 2 holes in the front of the mid section?

[AGosik]

HI I am rebuilding this motor and am worried about these 2 holes in the mid section front, facing the bow, On the the parts drawing they are shown but no mention of them or anything that might go there.The drive shaft runs up through there and the area seems sealed/water tight except for these holes. They have paint on in them as if nothing goes there THANK YOU for helping me with this issue...I don't want to start the motor until I know it is safe to do so!

 

[fdrgator]

Your observations are correct, the drive shaft tube is sealed. That is to keep exhaust, steam, and other nasty stuff away from the lower crankshaft and splines area. However, the drive shaft has to enter the water pump housing below. Some water comes out of the pump to provide an air seal. That water must be drained off or it will rise up in the drive shaft tube and get at the area just mentioned. So......the drain holes are provided to drain it off. They also give lots of opportunity for people to worry about them. Don't worry, they are intentional.

 

[steffco]

I recently had my lwr unit off on a 25 hp and had trouble getting this spacer tube re-installed due to damage from a overheat from the previous owner so I left it out. Bad Idea?
The motor does seem louder than it needs to be at low speed/rpm. I was wondering if this spacer tube that surrounds the driveshaft had anything to do with it until the exhaust starts comming out the prop at speed?

 

[fdrgator]

Very bad idea. It defeats the whole purpose of the tube. It will do severe damage up above, given enough time.

 

[steffco]

Roger That, I will replace it.
Do you think the tube has anything to do with exhaust back pressure?
Thanks

 

[AGosik]

Your observations are correct, the drive shaft tube is sealed. That is to keep exhaust, steam, and other nasty stuff away from the lower crankshaft and splines area. However, the drive shaft has to enter the water pump housing below. Some water comes out of the pump to provide an air seal. That water must be drained off or it will rise up in the drive shaft tube and get at the area just mentioned. So......the drain holes are provided to drain it off. They also give lots of opportunity for people to worry about them. Don't worry, they are intentional.

Thanks for the fast reply I was hoping it was some thing like that...now just to finish it and see hope it runs! Thanks again!

 

[fdrgator]

Roger That, I will replace it.
Do you think the tube has anything to do with exhaust back pressure?
Thanks

Yes, you would be able to hear it barking out the drain holes. Just how loud that would be, I can't really say.