Mariner 1980 150HP Questions for a guy that knows little

[Dqberry]

Hello,
I have a few questions and thank you for taking the time to read. History...purchased a 1980 bass boat with a 150hp Mariner and it has been sitting for several years. I replaced the starter and fired it up with a water hose. Ran for about 3 mins and didn't see any water out the tell tale. So I killed it.
Question 1
The overtempt switch that goes in the block is dry rotted off. So only a wire sticks out. Do I replace and if so is this for the diy guy
2
Pulled the thermostat housings and there were no thermostats on either side. Why? Should I replace? I only seen a little water on the starboard side thermostat housing.
3
Pulled the Poppit valve (I think that's right) which had probably hand a handful of water in the cap. Does this mean the pump is working?

I have ordered new thermostats and poppit valve kit and I am awaiting them. Just curious if I should go ahead and order the overtempt sensor and pump kit also.

Again thanks and sorry for being long winded.

 

[444]

Do the pump kit as well and check/change your bottom end oil. My over temp switch is also corroded off, I have never fixed it. I picked up a temp gauge and water pressure gauge for peace of mind but ran it for years without.

 

[Chris1956]

Without thermostats, you should have had water out the telltale very quickly. Check the telltale for a clog. Did you see water out the grating above and behind the prop? That is the main water discharge.

You still want to rebuild the waterpump and add thermostats and a poppit valve. Maybe the previous owner pulled the 'stats to mask a bad waterpump? That wont work for long....

Make sure you get the poppit rebuild kit for your exact motor. Merc changed them a few times.....

 

[CharlieB]

A water pump impeller that old could have lost some of the vanes. Make sure you have all the pieces out before reassembly.

 

[Faztbullet]

That motor needs t-stats or a restriction washer to cool properly. Nedd to replace that impeller first.