2003 Yamaha 50HP 4 Stroke Spark Advance?

[anderso8623]

I have a 2003 Yamaha 50hp 4 stroke F50TLRB. I was wondering if this motor had a mechanical spark advance. I am used to old 2 strokes where an advance lever was needed to Advance the spark at higher RPM.

Why?

I am having an issue with acceleration. Right around 1800-2000 RPM where my motor will bog down and die. I can typically get it past that RPM fast enough and then it runs fine from 2500- WOT. I have rebuilt the carbs completely. I have done a full tune up including spark plugs. It idles great right at 800 RPM.

My thought with spark advance, if mechanical, it may be sticking and needs to be greased. This was a routine maintenance procedure with my old 2 strokes.

if this is a different issue, please enlighten me.

 

[rejesterd]

The timing is computer-controlled. The pulser coil sends signals (generated by the flywheel magnet) to the CDI unit. So there is no manual adjustment, other than adjusting the pulser coil air gap (which I don't think is a common thing that needs to be done).

If you're sure the carburetors are cleaned and synced, then I would do a spark test. Make sure it can jump the gap specified in the service manual. If it can't, you possibly have a bad CDI unit or pulser coil.

Of course another possibility is low compression. Probably a good idea to do a compression test.

 

[99yam40]

I would think the CDI or ECU controls the timing using inputs from various things on the motor.
heck even my old C40TLRX 1999 model is that way