Yamaha 2a 2hp outboard starts but dies

[hurley]

My exact same outboard, and symptoms. Did everything you did then finally changed the one year old sparkling clean spark plug and it started and worked faultlessly.

 

[Shuggy]

No-one has mentioned compression. My checklist would be as follows, most of which you have done:

Check fuel is clean
Check fuel filter is clean
Check that fuel is getting to carb
Pressure test the fuel line into the carb and check that the needle valve is not leaking
Check for spark
Stick a bore scope into the cylinder and look for bore score
Check compression
Rebuild the carb and make sure the metering diaphragm has the correct clearance
Check that the impulse feed is working
If everything else checks out then bung a Chinese carb in there

If all of that fails then all hope is lost!

 

[obmij]

Here's a simple solution.

Take it to an outboard mechanic.

You think the carb looks clean. Has it been ultrasonically cleaned?

How many outboards do you service / repair a day?

Sixty quid and I reckon you'll have a functioning o/b

 

[alahol2]

I have to get the choke off very quickly, within the first 2-3 seconds after starting. It won't start without the choke unless already warmed up.
Is this true of all 2s?
or is there a jet blocked somewhere?
Runs fine once going.

 

[Shuggy]

I have to get the choke off very quickly, within the first 2-3 seconds after starting. It won't start without the choke unless already warmed up.
Is this true of all 2s?
or is there a jet blocked somewhere?
Runs fine once going.

Sounds normal to me.