NEED HELP! 2003 Yamaha LZ250TXRB HPDI

[ADSnegrita]

I have an engine problem! The engine will not go over 2500 rpm. Sometimes it runs fine then drops to 2000 rpm. The mechanic connected the computer to the engine, and it shows that the engine has 240 hour of operation and at 195 hours the Ignition Coil #2 and #3 stopped working.

After replacing the two ignition coils the problem persisted. The mechanic checked the wires to see if there was a signal to the ignition coil and there was none, but all wiring is in good condition with continuity. Looks like everything is pointing to the Engine Control Unit, is there any reason why two Ignition Coils would stop working? Do you know if these types of engines have ECU problems? This engine is over 11 years old, so I know it has more than 240 hours of operation.

Any help is appreciated. Thank you

[rodbolt17]

looks like you need to find a real mokanik.

what did the shift position switch indicate ??

look on your mokaniks wall, is there fuel and electrical certs from Yamaha.
that's your first clue he aint got a clue.
ask the mokanik what cylinders get shut OFF when the ECU sees a neutral ger selection.

then quit chasing ghosts and don't look for peter cottontail.

that laptop RARELY finds the issue, however it will tell the trained observant tech what the ECU "sees".

[greasyshaft]

If i had plenty of money I would just pay the mechanic to replace parts and watch him chase his tail. Could be very entertaining.

[rodbolt17]

the shift position switch is rather innocuous yet critical.
tells the ecu if the motor is in gear or not.
if the ecu sees an ingear signal and a start signal it limits rpm.
if the ecu sees a neutral signal it drops cyl's 2 and 3.
if the ECU sees a neutral signal AND rpm greater than about 1500 it drops 2,3,5 and 6.
whats funny is some idiots can still rev it past 4000 RPM in neutral.

switch operation AND proper cable adjustment is critical.

[ADSnegrita]

Thank you, rodbolt17, for your input. It makes sense.
I did not mentioned in my post that the boat is in Mexico. Therefore, The mechanics from the Yamaha dealers are very hesitant to work on my engine because its an American engine. They don't have any experience with HPDI or parts. They are the mechanics that suggested the replacement of the two Ignition Coils. Now I and working with an experience mechanic that is willing to work on it to find the problem.

Would it help to buy the service manual to work on this engine?

[rodbolt17]

yes and no.
depends on the training of the tech reading the manual.
the Yamaha manual is made for trained techs and explains nothing.

lucky for me the US taxpayer spent about 400K on my training.

however in exchange I gave up some health issues and 6 yrs of my life.