What does this do?

[azman]

you are looking at the side of the carb on my mercury 8HP 2 stroke

What's the little blue thing?

here you can see that an "arm" presses down on it when the "choke" is pulled out

Front view

anyway the blue "button" is frozen solid, and the beast won't start. is this the reason or coincidence?

P.S there is a spark on both plugs, and it turns over.

 

[monkfish24]

Have you got an engine serial number?

 

[azman]

Yes it's a 98 with the serial number 09977706

 

[monkfish24]

Ok may have found it here, bottom right diagram, It is the priming diaphragm pump AFAIK, it should return to high position after letting it go, it is spring loaded by the looks of things, it may need the pump seals replacing or just a general clean out of any old oil keeping it stuck.

http://www.boats.net/parts/search/M...-0G112449-BEL-S-N-9831799 & Below)/parts.html

sorry, wrong diagram! New old one replaced with this ^

 

[monkfish24]

Item 46 is a service kit, so will be able to be refurbished by yourself or your local OBM.

 

[azman]

Thank you very much. it was stuck in the up position, so if the primer wasn't working, I suspect it is almost definately the cause of not starting.

 

[VicS]

It is operated I think you will find by pulling the priming/slow running speed knob

RTM :-
http://download.brunswick-marine.com/filereader/file/pdf/4/enen/outboard/1998/2-stroke/10104z80.pdf

 

[azman]

I don't read manuals, I'm a bloke

But thanks for the link.

 

[BarryH]

I have the same engine. It is the primer.
I have issues with mine in that the gear actuator has soddin' broke. You wouldn't believe what Merc dealer wants for the "assembly", because "No" you can't just by the little nylon gear.......

 

[azman]

ohhhh go on, horrify me.

 

[VicS]

I have the same engine. It is the primer.
I have issues with mine in that the gear actuator has soddin' broke. You wouldn't believe what Merc dealer wants for the "assembly", because "No" you can't just by the little nylon gear.......

What part is broken then?

If its shown on the parts diagram as a separate part it should be available!

 

[corinthmistral]

as above, it is the fuel primer. when you pull out the choke it squirts fuel through the carb. i had the same on a mariner outboard. it should freely spring up and down. i used to pull and push the choke in and out 3 times (having first primed the carb with the bulb on the fuel line.) it always used to start first pull even in the winter. having primed it in this way i always found it didnt need any choke at all, even in winter.