1964 Johnson possible water pump problem

I have a 1964 40HP Johnson mo

I have a 1964 40HP Johnson model RDSL-26. I know nothing about boat motors so forgive my ignorance. At idle and slow speeds I am getting exhaust and water from an ejection port just below the cover at the back of the motor. I am also getting exhaust at the bottom of lower unit. Does water also eject from the lower unit??? Here is why I ask. At high speeds I don't see any water coming out of the top port. Is this normal for this motor?? At high speeds does all the water get pumped out of the lower unit? The motor has never over heated that I know of. However I have never run it at high speeds for very long. I am not sure if I have a problem or not.

"Paul.... That engine should p

"Paul.... That engine should pump water out through that large rear port with a great force at all speeds. It sounds like you are in need of a water pump replacement. If so, I suggest that you replace the complete water pump, not just a impeller.

However, before you do that, be sure to check the compression. It should be in the range of 100+ psi and even on both cylinders. Then check the spark. With the s/plugs out, that spark should jump a 1/4" gap with a strong blue flame on both cylinders. Let us know what you find.

Joe "