Mercruiser 120 Reliability questions

[KyleM]

A couple questions for some of the guru's in here.

Treat me as a I/O newby because, well, thats what Iam.

Iam going to look at an 1981 15 ' Peterborough with a mercruiser 2.5/120 within the next couple days.

Now.......

Are these motors reliable in a general sense? (if looked after ofcourse)

What kind of speeds will I be looking at?

What are some general issues with these motors that I should be aware of before I look at this thing and how will I be able to tell..

Im not looking for anything special but Iam looking for something practical, cheap to fix, and reliable.

How much gas will a motor like this eat if I were to troll for about 4 hours with it?



Thanks guys....

This forum is a great place for guys like me to learn.

If anyone has any cabinetry questions, feel free to ask LOL

 

[Rhadley]

Re: Mercruiser 120 Reliability questions

I have a 16' with a 120 in it. Engine is very economical and is smaller than most. Only issue with this engine is the tendancy to bog during acceleration; like when pulling a skier up. Make sure you test drinve it and see if it bogs when you hit the throttle. Also get it good and warm, then turn it off for a few minutes and see if it re-starts easily. That can also be an issue. Overall it is a good engine. You should be able to get 40MPH out of it, but that depends also on the prop.

Take a screwdriver and poke around to see if you find any soft spots anywhere in the boat. Older boats will rot from the iside out. Especially check the transom and under the deck around the ski storage area. I'd also open the outdrive drain screw barely, to see if the outdrive oil is milky, which indicates water in the fluid.

 

[KyleM]

Re: Mercruiser 120 Reliability questions

Thats easy enough...
Ive owned a fair share of outboards so hopefully atleast some knowledge will carry over.

Whats the reasoning behind the warm start-up?
Is it a sign of blow-by due to the rings warming up?

Theres no need for me to slam the throttle down.
Im just a simple fisherman, pull the tube the odd time.

I dont think I'll get a chance to test drive it before I buy it as its in the guys garage but I will try and get a "sea-worthy recipt" as I like to call them.

Thanks for your help, much appriciated.

 

[Rhadley]

Re: Mercruiser 120 Reliability questions

There can be various issues during warm startup related to fuel or even electrical. I had that problem intermittently for a long time and hope it is gone.