Yamaha F40 FETL MY2009

[freshslo]

I have problem with Yamaha F40 FETL MY2009, sometimes when i started they immediately shutdown. If I unscrew bolt for idle speed about 2cm they start normal and keep running at 800-900rpm. After driving approx 10-20min. when I release throttle they work around 1700rpm on idle. Then i have to screw bolt back to original position to get 800-900rpm on idle. This happens only time to time.

[almetelo]

Idle speed screw on a EFI motor???

That you unscrew 2cm (almost 1 in)?

What screw your talking about?

[greasyshaft]

Have an active test performed on the ISC valve on YDS, it is built into the throttle body. You can try cleaning them with combustion chamber cleaner. I have seen it happen before with same symptoms you describe.
You will also have to have the screw adjusted back to factory spec once the problem has been fixed.
\

There was also a TSI on high pressure fuel pump on this engine although I'm doubtful that it will be your problem might pay to check if yours was in the affected serial range.

[freshslo]

ICS valve? This is probably Intake Air Control Valve?

[boscoe99]

ISC for Idle Speed Control is also referred to as IAC for Idle Air Control.

If you have a fuel injected F40 then the idle speed is not adjustable. It is con*****ed by the ECU in conjunction with the ISC/IAC or Intake Air Control Valve if you will.

If someone tries to change the idle speed then the motor (ECU and ISC/IAC) are then going to try and make another change because they are now confused.

[rodbolt17]

but its a screw, it doesn't run right, I can tweak on it cause its a screw.

most folks that Do it with no understanding tend to create issues.

on a 4 stroke EFI motor the throttle shutter is set for air flow at the factory.

never EVER play with that screw.
any idle air is con*****ed by the ISC(IAC) .
if intake idle air is an issue test the ISC.
any codes will result in a high idle.

[boscoe99]

Now that I think about, the F40LA that was introduced here in the states in late 2008/early 2009 is a single throttle valve motor. It does not have an ISC/IAC. The idle air flow is con*****ed by the throttle valve itself.

Is the F40FETL a single electronic throttle valve model or is it a multiple mechanical throttle valve model?

To the OP, what is the complete serial number of your motor.

A Yamaha is not a Yamaha is not a Yamaha.

[greasyshaft]

Here in NZ the F40F has a single mechanical throttle. see illustration I posted above, it has all sorts of sorcery inside

[boscoe99]

Here in NZ the F40F has a single mechanical throttle. see illustration I posted above, it has all sorts of sorcery inside

That looks like an F40LA throttle valve.

[boscoe99]

Have an active test performed on the ISC valve on YDS, it is built into the throttle body. You can try cleaning them with combustion chamber cleaner. I have seen it happen before with same symptoms you describe.
You will also have to have the screw adjusted back to factory spec once the problem has been fixed.
\

There was also a TSI on high pressure fuel pump on this engine although I'm doubtful that it will be your problem might pay to check if yours was in the affected serial range.

Have you actually performed an active test for the ISC on a single throttle body F40? Have you performed the same test for a single throttle body F250 Offshore or SHO type motor? Do the test results appear to be the same?

[greasyshaft]

Yes I have done an isc test on The F40F same dynamic and static tests as any other yammie equipped with an isc valve .
You can see the linkage at the bottom of the throttle body 100‰ sure it is mechanical. never worked on an sho (haven't seen one actually)
Never done isc test on an offshore as they don't have one. (Here in NZ F225F, F250D, F300B)

Copied from F40F service Manual

[boscoe99]

Thanks for the info. I was thinking that the F40LA had an electronic throttle valve. Bad thinking on my part. I see now that it is a mechanical throttle valve with an integrated ISC valve.

[rodbolt17]

for the US market the SHO and F250 use an electronic throttle valve. no ISC the throttle is the ISC.

the rest yep done the ISC test.

I have learned to hate the EFI F40,50 and 60.

to hard to access them tiny parts.

but they run well.