1990 70hp Mercury advice???

I'm going to purchase my first boat & motor this week (used). The boat is 16' long. Very light 4 seater. The boat is a 1990 Crestliner. The motor is a 1990 70 HP Mercury. From the photos the motor and boat look very well taken care of. It looks like I could eat off the motor. An old guy has it and I don't think it was run very hard. I am taking a compression tester with me when I go to get it just in case these is something the old guy doesn't know.

Is there anything I should look for when inspecting this engine besides compression? It has power trim too.

Any advice to save me from a terrible transaction would be very much appreciated.

Thanks in advance.

Water Test the boat and motor. This is very important, I can't stress this enough. Run the boat at all throttle positions. Ask the owner when the last time the Thermostats and water pump was replaced. Also ask when the last time the carbs were done and gearcase oil was changed. get a good picture of the maintenance history for the motor.

Do a compression test!!!!!!!!!!!!!!! Do a compression test!!!!!!!!!!!!!!!!!!!!!!

Also check and see what the plugs look like before and after water test.

Make sure the motor doesn't overheat. There should be an alarm close to the controls that sounds when the motor gets hot. Ask and check that out. It easy to disable to hide an overheating problem (it happened to me).

You can always find a marine mechanic for about $50-100 to check it out before purchase.

Buy the motor and leave the boat - it's a collectors item.... Merc last produced a 70 horse in 1989, so if it's a 1990 model it is more than unique

Ok, seriously, obviously they have the production year of the motor incorrect but the 70 was a decent motor (shared it's powerhead with the 75 and the 90).

Agree, if you can take it out for a run that can tell you alot. Just having it running without hiccups, coughs or sneezes tells you that that the ignition and fuel system is probably working as it should.

I always "assume" a few things when buying a used motor 1) its not perfect - if it was it would not be for sale 2) the impeller needs changing 3) the lower gear oil needs changing 4) the sparkplugs need changing 5) the motor needs to be decarbed.

Go in with your eyes open and figure on spending some time and money on servicing it if you buy.