I recently bought a sailboat that had received little care for the last many
years. It has a 1983 Honda 7.5hp long shaft motor.

I couldn't get it to start so I took it to a local boat repair facility.
They admitted that they had never worked on Honda motors but they would take
care of me. (I would not have done this EXCEPT this company is a client of
mine) I asked them to get it running, tune it up, replace the impeller and
change the grease in the lower end. I supplied the new impeller.

Tuesday they called me to say that they couldn't get the motor to run and my
bill was $(the MAX I allocated for repair based on their maximum cost
estimate)
Wednesday I picked up the motor. This evening I have it running well BUT
there is no water discharge at the rear of the engine. It's in a 55 gal
drum.

Prior to tonight I've never seen this motor run. I assume there should be a
visable discharge of coolant. Is that an accurate assumption?

I found a pair of small holes above the water line at the rear of the motor.
When I cover them with my fingers while the motor is running, there is
considerably more bubbling from the exhaust.

What is involved in replacing the impeller? Are there instructions online?

Any help will be appreciated.