Yamaha z200Hpdi 2004

[Dave Blaber]

Hi there rodbolt hopefully you can solve my problem again, the motor starts ok, putting it in neutral and slowly revving it up is ok but when I throttle back to idle position it cuts out and when I try to rev it up quickly she won't and then cuts out, I have swapped vst,s over and still the same I also can't get more then 2400rpm out of the motor in gear, help !! Please

[rodbolt17]

then its time for actual testing.
check the voltage on the fuel pressure sensor.
should be, and stay, 2.8-3.2V.
check pink to black.
if its ok then test the shift position switch.

[Dave Blaber]

Thanks Rodbolt I am going to get a mechanic in to do the tests you have sugested, will let you know

[rodbolt17]

if taken to a trained tech the measurements wont be nessasary as it will show up on the laptop.

[Dave Blaber]

Hi Rodbolt I am having difficulty finding a tech with a laptop for that motor, I gave it a compression test all cylinders are 850kpa to 950 kpa which is good, but what I have found on two cylinders is the spark plugs only fire when I start the motor then stop sparking while the motor is still running, I am going to swap the coils around tomorrow, what I need to know is if that does not change anything what gives current to the coils?, thanks mate

[99yam40]

Do some more reading up on your motor, I believe it does not spark all plugs in neutral.
Take it to a good Yamaha shop

[rodbolt17]

in nuetral,running,cyls 2&3 do NOT spark.
in nuetral above about 1500 RPM cylinders 2,3,5,6 do NOT spark.
fouled plugs can also lead techs on goose chases,
thats why I also own a Kv tester.

[Dave Blaber]

Another question, if I disconnect the switch on the control arm it allows me to rev the engine in neutral, can I leave the switch disconnected?

[rodbolt17]

no
it must function as designed.
revving in N is a teat on a boar hog.
if all you want is RPM, remove the prop.
toss it in the creek.
problem solved.

if the ECU"sees" its in gear and gets a crank signal, it limits RPM.
if the ECU "sees" in in N, it cuts spark.
the switch simply must function or it wont run correctly.

[Dave Blaber]

Hi Rodbolt the reason why I asked is I do not want the ecu to cut spark I want it running on all cylinders at all times?

[99yam40]

he told you if the computer does not get the proper inputs then it will not run properly.

[Dave Blaber]

This motor has never run properly so I am trying everything, It's just another dud motor, thanks for all your help guys

[rodbolt17]

if properly taken care of,the Z200 runs well.
however it does require a bit more maintenance and tender loving care than a carbed 2 stroke.
from a maintenance stand point its wildly different than a carbed motor,most techs simply dont understand the electronics.
its actually very simple.
however you cannot fake out the ECU.
in N it runs on 4 cylinders,in N above about 1500 it runs on two cylinders.
the O2 sensor feedback is,supposedly, not used above 1500 RPM.
not my fault most techs cannot deal with HPDI.
mercury and BRP have the same issues.

HPDI takes a certain amount of test equipment and system knowledge to maintain.

[99yam40]

either get the proper equipment yourself and learn to do the testing or take it to someone that is trained and has the proper test equipment

[Dave Blaber]

Thanks for that, are there any more filters after the metal filter above the vst towards the high pressure fuel pump, and is there any way I can bypass the pressure regulator behind the vst?