1975 85hp Impeller / Waterflow

[cixelsyd]

I'm reviving a late 70's boat with an 85hp Merc. I wanted to check the motor before replacing flooring etc. in the boat.

I ran the motor tonite in the drive using a hose cup to supply water and idled the motor. Idled a bit fast, but I'll probably wait a tank or so to clear out the seal n store and fuel stabilizer thru the carbs.

When idling, I only see water flowing near the back of the fin. Does the cooling water normally exit near the back of the fin on this engine, or should it exit near the powerhead? How difficult is it to replace the impeller on this engine?

 

[diaric]

Re: 1975 85hp Impeller / Waterflow

should see water out exhaust of prop, through pee hole on bottom of cowling. if not impellor needs doing. not a hard job, few hours first time, less than an hour after that. search forum, for impeller/waterpump issues, you'll find lots of info

 

[Chris1956]

Re: 1975 85hp Impeller / Waterflow

Most of the water will exit out of the gratings above the prop and antiventilation plate. The telltales clog up easily. You will also see water come out of the square holes just below the powerhead, but usually only when the LU is in the water.

 

[cixelsyd]

Re: 1975 85hp Impeller / Waterflow

Thanks for the responses !!

I've ordered a service manual and will pick up a impeller kit. Any recommendations for online vendors? (Saw some at oldmercs that looked reasonable).

In the meantime, I'll keep a close eye on the "pee" when I get it in the water.

 

[diaric]

Re: 1975 85hp Impeller / Waterflow

you can order right from here, very reasonable. old mercs is good as they have hard to find stuff

 

[diaric]

Re: 1975 85hp Impeller / Waterflow

you can order right from here, very reasonable. old mercs is good as they have hard to find stuff

 

[Motor Boater Bill]

Re: 1975 85hp Impeller / Waterflow

Pee hole is almost always plugged by bugs if the motor sits for any time at all. Clear it with a wire and I bet it pees just fine--but change the impeller anyway because you want to know that is good for sure and old impellers don't pump a full flow especially at low RPMs, and can fail totally at just the wrong time.