Themostat

[luke1979]

Hi there please could someone help me I've ordered a theomstat kit for my mercury 15hp 2005 model and I gave the serial number to te people on line and it's came but it is a lot bigger size than the one That came out of the engine.

[luke1979]

I just wondering does the old one go smaller as it gets older or do u think it is the wrong size

[PeterM]

Am I remembering you had problems in the past with the engine?

[luke1979]

Yeah when I had engine rebuild I had themostat taken out but I want to put new one back in

[paintman]

Some things do shrink with old age but stats aren't one of them.
Sounds like you've got the wrong parts.
Don't know if this might be of any use, I've found it handy as a reference in the past (if only for the exploded diagrams):
http://www.crowleymarine.com/parts.html

[luke1979]

I gave the bloke the engine serial number of outboard and he sed it would fit

[spartacus]

Check against this. Normally you'll need a new gasket too.
http://www.mercurymarine.com/parts-a...parts-catalog/

[luke1979]

[luke1979]

That is it

[The Gurnard]

Hi Luke.. I fitted one a couple of months ago.. and initially it seemed a bit big in that it protruded from the hole it fits in ....a bit too much for the cover to go on.

Then I looked closely at the round rubber washer..shown just below the thermostat in the diagram you posted.

I then discovered there is a slot in the washer and it fits round the rim on the thermostat..so there is part of the washer above and below the rim...if that makes sense ? Then it fitted perfectly

Could that be your problem too ?