Yamaha F75 fuel injected. 2007

[Swifty1]

Been having my first trouble with my boat since new in 2007. It was starting and running fine till my last service, then it started idling high 2500 3000 rpms then slowly drops to a ruff idle. It was only dong this once its warm. Took it back to my service shop and they charged me $150 to tell me they could find nothing wrong. They then said if the trouble returns they will replace the idle air control module @ $257 for the part and another $185 labor. Took it back out on the lake and it was doing the exact same thing. The shop is under new ownership and I no longer trust them. I went and bought one myself and replaced it. First engine start it was at 3000 rpms, shut it down and restarted it, now its starting and dying right away. Is there an idle adjustment or do I need to get the Yamaha software to calibrate the new idle air module? Any help is welcome. I have added 1/2 tank of new gas and added a full can of seafoam before replacing the module.

 

[99yam40]

adding new gas to bad old gas make a bunch of bad gas.

If the idle control valve was sticking it could have hurt the ECU.

Does the service manual have a procedure for replacing that valve?

maybe finding a Yamaha shop with a master tech to troubleshoot the motor would be a good idea

 

[Swifty1]

Thank you for the reply. I have always added a gas conditioner since I only get out once a month or so and in southern calif there is no gas without ethanol .
It was running fine until it warmed up then the high idle and ruff idle would start happening. If I want it to stop I shut down the engine and wait 5 minuets starts up and runs fine till it gets up to speed then if I slow down turn off engine then trouble returns . If it was a gas issue I think it would run bad all the time?
I added some fresh gas and added seafoam on reading suggestions of others who have had the same trouble with their injected 4 strokes on the internet. I have ordered the service manuals and expect delivery in 2 weeks, hope there is some useful info inside. Is there a way to locate a shop with a master tech? I hate to throw money at someone just on their say so.

 

[99yam40]

try this link, put in you zip , then look for master tech certifications at the dealers near you
https://yamahaoutboards.com/en-us/f...9.1336950404.1529744015-1902684319.1526821226

 

[Swifty1]

Thank you for the link, tried it and the closest one is the same place that told me nothing is wrong and billed me $150 for that info. I will wait for the service manuals and see if I can figure this out myself.

 

[99yam40]

Did you ask if the master tech looked at your motor?
they usually have more than one tech working at a shop

re reading your post, what did they do on the last service that caused this high idle to start happening?

did they not see the high idle at the shop?

 

[Swifty1]

They only have one tech and some helpers, I have no clue if the he is a "master tech". The shop is listed in your link but that link is only Yamaha Dealers and not a listing where Master techs are located. I dropped the boat off as soon as the trouble started which was the first day I used it one week after the service. They said they could not find any trouble and charged me for labor to trouble shoot it and found nothing wrong. The tech did call me while he was working on it and asked me to describe the trouble. He then asked me not to say anything to the store manager about his call, not sure what that was about. I picked the boat up and the manager said they found nothing wrong but if the trouble returned they would replace the idle air control valve and quoted me the parts and labor for that work. They cant have done anything more then start it and stop it, they must have never gotten the motor up to speed. I saw the trouble after the very first minuet out on the water again and loaded the boat back up came home and started shopping for the control module.

.I looked on line and found where the control module was located and decided to do it myself since its only 2 screws and a few minuets to get to. I took the boat to a 2nd repair location and they informed me they only work on inboard engines. Next closest Yamaha Dealer is 70 miles away so I can wait for the shop manuals and see If I have to make that trip. ​

 

[99yam40]

what is your zip code so I can look for you?
If they do not have a Master tech listed under the shop name, they do not have one working there

like this
Details & Certifications

• Fullline Outboards
• Generators
• Factory Trained
• Master Technician

do a web search for Rodbolt17 to find a site he posts at to ask for help.
he is a Master tech

 

[Swifty1]

Update, good news found the trouble, it seems that when it was serviced they had somehow moved or rearranged the fuel rail for the fuel injectors. Each injector has 2 O rings, one on top for the fuel rail and one into the cylinder. One of those O rings was leaking and the motor was acting as if it was a vacuum leak. Pulled the injectors reseated them and its all back to normal.

 

[99yam40]

Good to hear you are going good again,
but a leak on fuel rail(which is pressurized) will not act like a vacuum leak.
a leak will allow fuel to come out not suck in air

edit
being it was the oring at the cylinder maybe the pressurize fuel was not the problem area,
the bad seal was allowing air into the cylinder besides what was coming past the throttle plate