Yamaha 9.9 outboard 2stroke running poorly

[mattyc1959]

Hello from the Abacos,

My 9.9 Yamaha outboard (a 2002 2-STROKE ) is acting up. Basically it runs fine at idle. Well just after it starts up it might miss a couple of times but then it idles fine. As soon as the throttle is applied, it bogs down and has no power and just sort of blubbers along. Gas is new, I have had the carb apart 3x to clean it,the jets checked out, the float is not stuck,etc. Checked all the electrical connections including the grounds and changed the plugs. Took the fuel filter apart - no problem there. The fuel pump is working. I pulled out the plugs out again this morning while it was still dark and both showed a good spark when I pulled the starter. It has spark fuel and air. What am I missing? Any suggestions?

[Tucker]

How do you know the fuel pump is good? Did you unbolt it keeping fuel lines attached and pump the bulb?

[Tucker]

Abacos eh?? I have 3" of snow on the ground and its 32 out and we're almost a week into Spring.

[arny]

Possible defect/leaking gasket labyrinth on crankshaft between cylinders.Up to 2004 it was made of rubber(not a good idea). Later it was made of aluminium.Crankshaft have to be taken apart to change labyrinth seal.

[2strokesmoke]

Possible defect/leaking gasket labyrinth on crankshaft between cylinders.Up to 2004 it was made of rubber(not a good idea). Later it was made of aluminium.Crankshaft have to be taken apart to change labyrinth seal.

I have a 2000 9.9 2 stroke MSHY, I checked the parts lists and cant find the labyrinth seal. Plenty of washers, seals etc. but nothing that says labyrinth. I searched and found labyrinth seals in the 6 hp and some higher hp motors but not mine.
Would calling Yamaha help me find out if there was some kind of known issue with these?