1996 50hp won't rev past 2300rpm

[Dr Jizm]

Hi,

got a wierd one here, went out today and the engine would not rev past 2300rpm, no alarm sounded or anything so don't think it was that. But it was like the motor was 'bouncing' at those revs and would not go any higher no matter what. I earthed out the pink alarm wire and that brought on the buzzer and the engine seemed to limit itself to just under 3000rpm but no 'bouncing' as such. I had a good look at the manual and I am thinking maybe a dodgy charge coil (high speed) or suspect CDI unit maybe. Got home and had a look at it in a test tank and low and behold the fault had disappeared but it has done this before! Anyone got any thoughts on this? Does my motor have a low and high speed charge coil? Anyone know the wire colours, as the manual is a bit inaccurate!
thanks

 

[Dr Jizm]

Re: 1996 50hp won't rev past 2300rpm

update.......

Ran it in a test tank, in gear at 2000rpm or so, for an about an hour and the prob did not return. It ran as sweet as a nut and I had to stop it in the end as the tank water was getting very warm! The only thing I did find was that the flywheel had worn through one of the crank position sensor wires, so I repaired and re-routed that. I dis-connected that as a test and the motor ran a little rough but not too bad. I also put the bare wire to earth to see if it created the fault but i didn't so no luck there anyway.
Couple of things I am not sure of:
Why does my motor have a crank position sensor?
Is it to govern the timing of the spark as the motor only appears to have one pulsar coil not three as I expected?
Does my motor have a high and low speed charge coils as there are only 2 wires (brown & blue) when I was expecting three, unless it grounds through the motor?
Why do the lighting coils have a red link wire between them as none of this really corresponds to the schematic (seloc manual) I have?
thanks