mercury 2.2 outboard - cooling system blockage

[Fire99]

Well hook or by crook, i've just stripped and overhauled a Mariner 2.5 today.. (On inspection most of which could of been left but worth doing) Ok my motor is prob a fair bit newer than yours but I doubt it's much different.

(As others have said) First check the water pump impellar behind the prop and if it hasn't been replaced in a long time, replace it anyway as it's only a few quid.

The water telltale (cooling outlet) comes from top of the block and as Lakesailor says there are two water inlets in the bottom of the powerhead which are pretty small and easy to clog up in time. If water isn't coming out then the head isn't getting cooled properly.

I'd certainly buy a new powerhead to leg gasket and head gasket since for the little money they are it's pointless adding another possible trouble to the bag.

Good news is that it's a very simple little engine and easy to work on and work out where the water channels are and to make sure they're clear.

[PaulR]

thanks everyone - will clear the workbench of son's stuff!! and have a go - lakesailor - great photo -thankyou

Paul

[PaulR]

eureka - it works - have taken it apart as photo above - flushed out salt build up and put it all back together - been down to club and test run and eureka it runs and good flow of water from pipe exiting from engine housing - thanks everyone

[Fire99]

Originally Posted by PaulR

eureka - it works - have taken it apart as photo above - flushed out salt build up and put it all back together - been down to club and test run and eureka it runs and good flow of water from pipe exiting from engine housing - thanks everyone

Well done mate. It's good seeing it all working from your own hands isn't it? Glad you sorted it.

[Lakesailor]

Plus you get to understand what's happening under the plastic covers.
Priceless.