Yamaha 9.9 Outboard Problems (2013)

[ausnp84]

Hey guys, anyone have experience with a Yammy 9.9 4 stroke? Having finished refitting our cat this is the last issue on the list.

From cold it starts ok but then idles really high, then drops down, then really high, etc Once it’s warm it generally idles pretty even.

It also seems to bog down at mid revs and then increasing the throttle a bit really accelerates the boat forward.

Today we left the dock, I had it at 3/4 throttle and opened it to WOT just for a few seconds then backed it down again, and it cut out. We got it restarted on a single key turn and it ran fine for another few mins, but then the harbour entrance had a bit of swell (less than 1m) and it cut again. Got it running on second key turn, turned around, and it ran fine all the way back to the dock.

We’ve cleaned the carb 4 times, replaced fuel hoses, the primer bulb, fresh fuel, new spark plugs, and scrubbed both fuel tanks. Any thoughts? Carb rebuild time? Fuel pump issue?

N

[ggray]

A friend suggested to me that with most small motors...and he was including more than just outboards...you can buy a new carburetor for not much more than the cost of a rebuild kit.

I thought I had checked, and didn't find this to be the case, so bought a rebuild kit to fix the poor running of a 30 hp Tohatsu (2 stroke though) and preformed the operation.

Was probably my inexperience, but this didn't help much.

Long winded answer, but I searched again and found the correct carb this time, and it was indeed just a little more than the rebuild kit. I bought one, and that was the end of my troubles.

So the carb may or may not be your problem, but a brand new one probably isn't too expensive.

[ausnp84]

Thanks - we’re now thinking a new carb might be the best way forward as well!

N