2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

[phockeye]

motor starts & idles fine but has no power when you throttle up under load the charge coil tested bad so I replaced that and since then I've swapped out or changed all ignition components, carb is spotless, fuel pump looks good, checked fuel line and gas tank on another motor and that tests good as well what the heck is wrong with this thing could the exhaust be plugged? any ideas anyone?

 

[99yam40]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

Have you check to see if timing is advancing to spec

 

[phockeye]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

Have you check to see if timing is advancing to spec

yup very simple procedure

 

[99yam40]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

If compression is good and spark & timing are good at problem RPM then you are left with fuel/air ratio issue

 

[phockeye]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

compression is 115 on # 1 and 117 on # 2, do you think I should swap out the carb & fuel pump (I have 2 more of these that run fine) or should I pull the exhaust cover? maybe I got off on the wrong path with the ignition (the charge coil tested bad for sure) the timing is set by gauge according to piston position not with a timing light (according to Seloc manual)

 

[99yam40]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

I just asked if you checked to see if the timing is advancing to the proper WOT timing listed in manual.
That takes a timing light to see where it is firing at

 

[phockeye]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

I just asked if you checked to see if the timing is advancing to the proper WOT timing listed in manual.
That take a timing light to see where it is firing at

will double check this today, however as far as I can remember the manual does not discuss the use of a timing light with these motors.........Thanks!!

 

[99yam40]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

So , how did you check to see if the idle and WOT timing was in spec without a timing light?

CDI controls the timing as far as I know on these modern motors

 

[phockeye]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

turn the flywheel until timing mark lines up with the 30 degree mark (as specified in the specs) turn the throttle to wide open position then check to make sure pointer on slide lines up with timing mark. that's it according to seloc manual no further checks required if these line up. don't even have to run the motor no other procedure is discussed if the marks don't line up a dial gauge is used to measure # 1 piston position before making adjustments

 

[phockeye]

Re: 2001 9.9 2 stroke yamaha what the heck is wrong with this thing?

FYI haven't water tested yet but I'm pretty sure I found the problem, I pulled the lower unit yesterday and found the lower exhaust housing to be plugged with mud, someone must have had the thing literally buried in the silt lake bottom, never seen this happen before live & learn I guess ...Thanks again for the replies