Yamaha F150 idle and stalling

[Enzo200500]

F150a
Production date 07/12
136 hrs run time.

Hi everyone from the UK.
I have found and read most of the issues on the Idle Speed Con*****er issues. Especially the ‘rodbolt’ adjustment for the TPS and butterflies.

Did this procedure today on the engine and it enabled the tickover to be restored back to 700 from the 500/400 rpm’s it was sitting at!

I do not currently have the YDS software to cycle the ISC valve, and the only noise with the ignition key on is the fuel pump priming, no noise or visual movement from the ISC valve when laid on top of engine.

So my first question is, can I run with the ISC disconnected, but still fitted in the manifold, without throwing any warning lights, as I have seen a lot of people mention the ECU being damaged.

Secondly, what version of the YDS software would I need for my year of engine. I have seen two versions mentioned?

Thirdly, are the ISC valves direct from China etc ok for the job, or is it OEM all the way?

The engine only had 28 hrs showing when I got the boat in January, and has been absolutely perfect right up until this issue decided to ruin a days fishing.

Thankyou to everyone for such a great resource.

Steve.

[99yam40]

Not much help from me, but do you hear the ISC rattle (resetting to 100%) when you turn off the key?

not sure how you could get the motor to idle as it should if the ISC is not moving when it should

[TownsendsFJR1300]

I believe this kit is what you need:

https://www.powersports-diag.com/en/...ostic-kit.html

I didn't spend nearly that much, many years ago.


Here's a video of the valve cycling: https://vimeo.com/264625510

As 99Yam posted, you should only hear the rattling for maybe 2 seconds when the key is turned off(it's re-setting).
I believe it's a "stepper motor" so the ECU, adjusting the idle, I would think movement would be very little.

If it's rattling at key off and idles at 700 (operating temp), you should be good to go.



.

[Enzo200500]

Hi guys, the only noise I get is the fuel pump priming.

Even with the ISC valve sitting on top of the engine, like in the video, it does not move, or make any noises!

I’ll pop back down to the boat this morning to balance the Throttle Bodies, and bring the valve home for further ‘inspection’.

Thankyou for your help.

steve.

[Enzo200500]

Ordered that YDS kit too!

thankyou for the link.

steve.

[Enzo200500]

My Robalo R180 being lifted ready for me to service it a few weeks back.

[99yam40]

Hi guys, the only noise I get is the fuel pump priming.

Even with the ISC valve sitting on top of the engine, like in the video, it does not move, or make any noises!

I’ll pop back down to the boat this morning to balance the Throttle Bodies, and bring the valve home for further ‘inspection’.

Thankyou for your help.

steve.

have you listened when turning the key to the off position after the motor has been running?
you will not see or hear the ISC move when you turn the key to on, it should be sitting at 100 % until the motor is running and then is adjusts as needed to control the idle

[Enzo200500]

No noise at all from the valve, even when turning off key from running.

I have the unit at home now, I may investigate the internals, or just wait for the YDS kit to arrive, then run some tests using the laptop!

[pstephens46]

No noise at all from the valve, even when turning off key from running.

I have the unit at home now, I may investigate the internals, or just wait for the YDS kit to arrive, then run some tests using the laptop!

Do you have the cowling removed when you are trying to listen? You cannot disconnect the valve and run normally. How would the motor get any air at idle? If you can get the YDS to connect properly, there is an ISC test function. The motor has to be running at idle during the test. You need to determine if the ISC truly is faulty.

[Enzo200500]

Cowling is removed when testing.

The YDS kit is due to arrive around the 29th, I’ll try to get back down to the boat after then.

Been reading up on the Com 1 port issues as well!

will report back when I find out something.

Thankyou for your help everyone.

steve.

[Enzo200500]

The butterflies have been opened using the stop screw and TPS adjusted back to 0.7v when on 700 rpm tickover. The input voltage is exactly 5v into the TPS.

This setup effectively ‘bypasses’ the ISC valve, except for the faster idle when cold.

Not a perfect situation, but at least I can safely move the boat throughout the marina on tickover!

steve.

[Enzo200500]

Just to keep the thread updated, received the YDS cable and disc from Europe, Slovenia it was posted from, a couple of days back.

loaded onto the laptop and spent a little while finding and changing over to Com port 1.

Finally managed to get down to the boat this morning, it had ice everywhere, due to the rainwater freezing!

Found the 3-pin plug and it connected to the laptop straight away.

i did flick the ignition beforehand to activate the ecu.

Tried to cycle the ISC through the YDS and it only made a slight noise, no physical movement on the plunger.

Dropped tickover to 750 and reset the TPS output, monitoring through the YDS screen.

Typically, the three units I ordered from China were at home when I returned!

I may try them on the engine tomorrow, or just go fishing....... FD14B80C-C96C-4A22-892F-3B8603B71E2B.jpegED736AAE-8BD0-473E-AA18-76956E861BE2.jpeg

[TownsendsFJR1300]

Sounds like you found the issue!

A good way to start the new year!

[Enzo200500]

I hope so Scott.

I did run the boat out fishing yesterday. There was ice on the deck all day!

About 35 miles travelled and the engine ran perfectly at all rpm’s.

The only issue is when first started in the frosty morning, it almost stumbled on tickover. A slight increase on the lever in neutral sorted that cold start problem.

Once warmed, it started and idled fine, all day.

I will pop down to the boat with laptop today and try out these replacement ISC valves.......

[Enzo200500]

Went back down to the boat and tested the three valves from China.
Every single one worked perfectly.

Total cost of all three valves, delivered within 10 days, from China was £9.57!!
The genuine Mitsubishi valve here the the UK is over £350.


I’ll keep one on the boat as a spare and ordered some more!

A188CA84-EBD1-461B-8500-C549F8413E40.jpeg

Thankyou for such a great resource of helpful information everyone.

Steve.