Engine flooding (over fuel)

[Gvdmerwe]

Hi Guys,

I have a Yamaha 85AET 3 cylinder outboard, serial 686L405597 it looks like.

I will try my best describing the fault and my attempts at solving.

The engine starts with a flick of the switch and idles smooth at +- 1000rpm and if I floor it it revs up very quick to full rpm and pulls/push the boat like it should but then starts smoking and studdering and the rpm gauge falls back to maybe 2000rpm or so and it doesnt do much in delivering power.

Attempts:

I bypassed the fuel pump to see if it doesnt over pressure the cabs, and force fuel into the main jet, used a fuel vessel over the engine to gravity feed - same problem.

If i pinch the fuel line it does the same until the carbs start running dry then it revs up normally and dies.

If i rev it without load, not in gear, it revs to 5500rpm quick and stays.

Cleaned carbs nothing funny in them, needles seating good. If i look into the carb throat whilst running wot i see a stream of fuel spraying out the main jet. The engine is very heavy on fuel, no power, no revs, smoking.

I syncd the carbs and the timing seems good. (I am not a expert but it looks best from the workshop manual).

Would appreciate very much any one pointing me into a direction or at least a tip or a hint as to what to do. Or if somebody had a similar problem.

I had the boat at a mechanic, they fitted a test disk prop and it runns fine, power no flooding etc. Took it home and to the dam, and exactly the same problem.

Please help.

Thanks
Gerrit

[99yam40]

check your alarm system
sounds like you are getting an alarm and hitting the RPM reduction due to over heat or low oil level as it reduces/ limits RPM to about 2000

[Gvdmerwe]

I dont think it comes to any safety features. I dont think its got any. I will try andpost a video of the mechanic test and the self test.

[99yam40]

then how are you suppose to know what is happening with the motor?

Gauges should have lights and other indicators to show alarms.

remote controls usually have a buzzer built into them
If this motor is a premix model the overheat may be the only thing that will cause an alarm and RPM reduction/limit

If it will run fine during the testing but not when pushing the boat the only thing I can think of that may be different is the length of time it is run. And once run long enough the motor is overheating

[Gvdmerwe]

It doesnt have a autolube system, and assuming the buzzer is working nothing sounded. The mix we use is 50 to 1. The engine stays cool to the touch.

https://m.youtube.com/watch?v=GCHwhlbjkrU in the end of the video the fuel is depleting and the revs pick up before i un pinch the pipe.

https://m.youtube.com/watch?v=oHsdE_Fo864 test at the mechanic yard.

Dont know if this will help.