Expert Needed Yamaha 200 HPDI

[fowler2709]

2003 Yamaha Z200TXRB

Recently had 100 hour service done, impeller replaced, shift shaft replaced (don't ask why please). Took the boat out yesterday and everything seemed fine at first, stopped in a cove for a few minutes with motor turned off. Cranked motor back up, drove slowly out of cove, went to plane off and RPMs were limited (assuming guardian mode was activated). Turned motor off, put it in gear, then put down throttle, boat planed off flawlessly. Recreated initial scenario by turning motor off, driving slowly a few minutes, tried to plane off and guardian mode was activated once again. Turned motor off, turned it back on, put it into gear and put down throttle and boat planed off easily again. It is easy to recreate the problem but I have no idea how to fix it. Something seems to be activating guardian mode and I have no idea what it is. Oil levels are fine, no overheating, no alarms, all gagues show motor is functioning normally. Thanks in advance for the help.

[99yam40]

Test and fix the alarm system if it is not functioning properly.
Pull and test/ replace the tstats and PRV.
PRV sticking open can cause low speed/RPM over heat

[Hollywoodfish]

On the engine side, at the end of the shift cable there is a shift position switch (two wires). When the circuit is slosed it tells the computer that the motor is in gear. When this goes bad the engine remains in safe mode. If you have a way to get it hooked up to the YDS (Yamaha Dyagnostic Software) then you can see if it is working by putting the throttle in and out of gear. You can also bridge the wires and close the circuit. Beware that if you close the circuit you will no longer be able to operate in safe mode. It is a relatively cheap fix. Good Luck and please post your findings.

[mitch]

...really you need to connect to yds to see what is going on

[Hollywoodfish]

You don't need to, but it helps to diagnose certain things.
I found out the expensive way that replacing the wrong parts just wastes $$. So, now I bought the cable and software. It has been a worthy investment.