40 ho won't start in cold weather

[trapper 12]

Hi
Thanks for letting me join this forum.

I have recently purchased a 2007 yamaha 40 hp outboard with pull start. It has very low hours and was well taken care of. I purchased this this motor mainly for duck hunting in winter when the temperature can range from 0 to -35 Celsius. The problem is that it won't start when it gets cold. I have cleaned the carburetors and replaced the plugs but still won't go but bring it in the shed in the warm and it well start with 2 or 3 pulls every time. I even change the oil with a lighter weight one (5w-30), and you can pull it over the same as it was summer. Any help would be appreciated.

[TownsendsFJR1300]

Your model should have an automatic fuel enrichment device, referred to by Yamaha as Primestart.

Check the red lever on the carburetor to verify that it is in the automatic position. The lever/knob should be in the full counterclockwise position.

If it is in the automatic position then rotate it clockwise until it is in the manual enrichment mode. See if the motor starts any easier, or the same, in the manual enrichment mode.

The presumption is that that you are pumping the primer ball until it gets firm before the first cold start attempt of the day.

[boscoe99]

Hello.

You are welcome.

Is this a four stroke or two stroke motor?

I will stick my neck out and hazard a guess that it is a four stroke. But...

An F40, if this is a four stroke model, won't have a Primestart override lever.

[trapper 12]

Yes this is a four stroke. Sorry about that the

[boscoe99]

What is the complete model identity please?

[trapper 12]

It is just a 40 hp four stroke with manual start with a tiller handle. 3 cylinders with carburetors. No battery hook up at all.

[rodbolt17]

try this.
pump the primer to insure the carb bowls are full.
rapidly open the throttle 3-4 times.
now try it.
those carbs use actual accelerator pumps.
add a touch of fuel with them.

[boscoe99]

It is just a 40 hp four stroke with manual start with a tiller handle. 3 cylinders with carburetors. No battery hook up at all.

Do you go into an automobile parts shop or service shop and tell them you need an octoflugaron for your car, just a V6 car with a normal starter motor with four tires? Six cylinders with fuel injection? With aluminum wheels on the car? And expect the guy to know what specific octoflugaron you need?

The complete model (and serial number) for you motor can be found on the side of the motor. A label will be on the left hand side. Write this all down in your owner's manual so that you will know in the future. It can be very important. See image below:

[99yam40]

OP pick one from these that is your motor
2006 and Later Yamaha Outboard Parts