mercury 2.2 outboard - cooling system blockage

PaulR

PaulR

Well-Known Member
Joined
9 Sep 2001
Messages
1,000
Location
Home West Sussex, Boat on Mooring in Gosport
Visit site
sods law- had a clear out this week of stacks of sailing magazines - one of which I am sure had a guide to diy servicing 2 stroke outboard - today - stripping boat for winter layup took our mercury 2.2 to flush through with fresh water before layup and no water coming out of tell tale under engine cowling - must be a blockage somewhere - has anyone please got either a manual for the 2.2 and can email me the section on cooling system so I can have a go or point me in the right direction as to where blockage is most likely to be found ?

thanks all
 
My Merc. 2.2 had prostate problems, which I cured by removing the head and cleaning out the very narrow cooling water passage around the head/block joint. It was full of gunge caused by corrosion of the aluminium I should think. There isn't a cooling jacket as such, just this groove. It's not a difficult job, and I reused the old head gasket. It's been fine now for 3 or 4 years of infrequent (ab)use.
If you want a copy of part of the manual, PM me, but I won't be able to send it 'til after next w/e.
 
First thing to check, if you have not already done so is, that it is not just the tell tale itself blocked. Take it off but be careful of the fitting at the engine end as it is probably plastic, or just try back flushing it.

When was the pump impeller last changed? Should be done every few years Some might even suggest every year.

This is an engine from the mid/late 1980s ??

If I have found the right one the pump is located behind the prop so easy to get at.

If it is 20 odd years old then there's a good chance the water passages are getting scaled and blocked but removing the head and digging them out looks like a fairly straightforward job.
 
These two holes (arrowed, right) are the little culprits. Spin a twist drill through them to enlarge them a touch.
(the power head is removed from the leg in this piccy, the cooling passages are outlined in yellow)

Tohatsucooling.jpg
 
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 said:
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
Click to expand...

Well done mate. It's good seeing it all working from your own hands isn't it? Glad you sorted it.
 
You must log in or register to reply here.

Share this page

Top