Mariner 8M Workshop manual/advice

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changeman

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Does anyone know if the workshop manual for this outboard is available online or have a copy they can email to me?
I don't even have a basic user manual and am experiencing overheating and engine cutting out.
Alternatively, some advice would be welcome, bearing in mind I will need to know where the bits being referred to are located on the engine.

Thanks
 
Try this site for down loadable parts diagraghms and lists. Once you have the pictures you are half way there.

Overheating is usually caused by under-cooling, pump/impellor, blocked waterways etc, faulty thermostat.
 
[ QUOTE ]
Try this site

[/ QUOTE ] ???? Link missing!!!

Try the parts catalog at http://www.crowleymarine.com/index.cfm for exploded diagrams.

causes can be any of those mentioned.

Replace pump impeller esp if not done recently.

Thermostat, assuming there is one, easy to check.
Blocked waterways rather more difficult requiring dismantling to clear properly.
 
On help;if the cooling water stream is hot or intermittent,check the thermostat before removing the impeller/water pump.I did'nt do that & regretted it!The thermostat can become clogged & jammed only half open.If in doubt remove it.
 
[ QUOTE ]
If in doubt remove it

[/ QUOTE ] Don't remove it and run without it. the engine is designed to operate at the temperature determined by the thermostat.

If you leave it out, all other things performing normally, the cylinder will be over cooled although the piston and possibly the rings will still just about reach their normal temperature which means that the piston to bore clearance will be less than designed to be. Scuffing or even seizure could be the final result!
 
[ QUOTE ]
[ QUOTE ]
If in doubt remove it

[/ QUOTE ] Don't remove it and run without it. the engine is designed to operate at the temperature determined by the thermostat.

If you leave it out, all other things performing normally, the cylinder will be over cooled although the piston and possibly the rings will still just about reach their normal temperature which means that the piston to bore clearance will be less than designed to be. Scuffing or even seizure could be the final result!

[/ QUOTE ]

My 9.9 Mercury ran perfectly alright for 5/6 years with the thermostat not working at all but jammed open.If it had jammed closed the conditions you highlight would certainly have occurred.
The thermostats only role seems to be to control the water supply for a few seconds at start up & since we don't live in Antarctica you have got to question it's real value.
I have got a new thermostat fitted now at the cost of thirty quid & I am starting to suspect that the damn thing is restricting the water supply during normal running because the "tell tail" seems to be running hot & not as strongly as before.I may yet remove it altogether rather than risk a seizure.
 
I'm not familiar with the layout of the Mercury cooling system but the purpose of the thermostat in any engine is to control its temperature to the level at which it is designed to operate.

If the flow from the tell tale is reduced and hotter than normal I would suspect the water pump impeller may be due for replacement especially if its much more than 3 or 4 years old. Although of course the system could be obstructed, by scale and corrosion perhaps. For just reduced telltale flow blockage of the telltale is the first thing to investigate.

However the thermostat is easily accessible so an obvious thing to check before tackling the more complex job of servicing the water pump
 
I completely overhauled the water pump replacing the impeller before finding the faulty thermostat & not only was it seized partially or fully open & bunged up with a fair amount of debrie but I then realized upon fitting a new one that it had never worked during my ownership.
All in all it looks like a damned liability & I note that it was not fitted to earlier models of at least the 6/8 HP according to my manual.
I might take it out & see if that improves the flow because to much water has got to be better than to little.
 
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