Workshop manual for 2006 Yamaha 40 2 stroke.

[Bremar]

Hi,
I have the above 2 stroke 3 cylinder Yamaha that has a misfire problem. I’ve done a compression test and all cylinders are ok. The engine will stop if I pull the middle spark plug cap off. Pulling the bottom or top plugs off the spark plugs doesn’t change the engine note appreciably. I’ve stripped the carbs and thoroughly cleaned them with carb cleaner and compressed air. I’ve swapped over the ignition coils on the plugs and nothing changes, only the middle cylinder seems to continue to power the engine.


Now I am at a loss and need more detailed info from a workshop manuel for eg ignition timeing (does anyone know it?) I’m happy to pay for one but can not find one to buy anywhere as I can’t find a reference for my engine.
Thank you
Bremar.

[Davie]

This engine has primestart. Is the red over ride in the tick position? Also look at the 3 wires coming from CDI unit. It’s possible cylinder 3 coil is plugged into cylinder 1 from CDI. They have numbers on the black wire with the white stripe. (Number 1 cylinder is at the top.

[Roflhat]

As Davie said make sure they're firing the correct cylinders, check to see if you have a spark on all plugs. If not then check all the connections on the coils especially the earths

[Bremar]

Thanks for the reply’s.
The manual choke leaver has 3 settings. Normal open and closed. It is set to normal. ( I have tried for over an hour this morning to upload a photo from my iPhone. I’ve resized to less than 300kb made it square and still says it’s an invalid JPEG’s file so I’ve had to give up on that sorry)
Not often you find manufacturers naming the wires 1 ,2 etc. Checked those and they are ok. All wire seem to be connected correctly. I have also checked the coil earths

I found a mention of a problem with the oil level sensor and the pink wire. Some have suggested disabling the sensor resolves a misfire because it’s also connected to the temp sensor! Does anyone know how exactly to disable the oil sensor.

My outboard is a 2006 Yamaha 40 hp 3 cylinder 2 stroke. 40YETO. 68PK. L. 1001350. J. Would that be a “service manual for a 40X” ?? I’m happy to buy one but can’t find a manual referencing my model. Help!

Not being able to find how to reference my outboard makes it difficult to buy spares in advance if dismantling.

Does anyone know the timeing setting for this model? And any advise on sorhee critical settings.

One final request. If I can’t sort this misfire myself does anyone have any recommendation for a localish repairer/service engineer who would be good with this Yamaha. I live in Stratford upon Avon but am willing to travel for an independent specialist if necessary.

Thank you all in advance and for the suggestions so far.

Bremar

[Davie]

Alarm overheat and low oil will only come in after +/- 1100 rpm. Pull the pink wire at cdi unit to disable. The 40x is a twin cylinder engine, completely different machine. Send me your email address and I will send a parts book.

[Roflhat]

Have you checked the plugs for spark? We had a misfiring Yam 40 last week, turned out to be a dud top plug. Brand new plugs as well, pretty rare but it does happen. After a 5 min run the other 2 were hot the top was still cold.
New plug and it's all good

[Bremar]

Thank you davie and Roflhat for your replies.
I will have a go with the pink wire tomorrow after work. I’ve slso messaged you with my email. Thanks for that offer. I really appreciate it.
Yes all the plugs spark. But only no 2 cylinder is firing. It doesn’t seem to need it but I’ve irdered a new fuel pump. I used the primer bulb to manually pressure the system while engine running and without the air box you can plainly see fuel being sucked in.
Maybe a very weak spark.? Can this be the cdi?
Thanks again anyway.
Bremar

[Bremar]

Hi davie
I tried sending a private message but your in box is full and it won’t sccept anymore till cleared
Do you know how that engine is referenced as far as buying parts is concerned?
Thanks again and it is really helpful if you
Email is bremar@ntlworld.com

Bremar.

[Bremar]

I managed to get some service data sheets from BHG marine ltd in lymington.
Andy was very helpful. If I can’t sort the misfire myself then I’ll be taking it to them. They appear to specialise in Yamaha.
Ivd not had many helpful replies so I guess people don’t know anything much about these Yamaha 40YETO engines. I’ve attached the three sheets here to help others

[Bremar]

I’ll try again to upload
Service Data1.pdf

Service Data2.pdf

Service Data3.pdf