2007 80 hp jet very hard to start when cold

[Just like to fish]

My 2007 Yamaha 80 hp jet (115 power head) very hard to start when cold, fine after that and runs good. I suspect the auto electric choke maybe not working. Should I hear it click or something when the key switch is on and pushed in, I am not even sure just where to located the choke and assume it has a solenoid that I should hear engage. I don't think there is a manual choke on it. Any advise would be appreciated for checking this out. Thanks for welcoming me to this forum.

[TownsendsFJR1300]

Is the an out board engine with a jet drive? And is it 80 HP or 115, don't think it can both...There is no 80 HP listed for the US.. Where are you located?

Model #? Should be 3 or 4 letters..

2 or 4 stroke?

Which one of these?: http://www.boats.net/parts/search/Ya...ter/parts.html

[Just like to fish]

It says 80 hp on the motor cover and it is an outboard jet drive. I just think it is the same power head as the 115 hp and they just derate the hp when there is a jet drive in stead of a prop drive, though I could be mistaken. It is a 4 stroke with no tiller handle, but controls are by the steering wheel. Thanks

[Just like to fish]

I am in Washington state, forgot to add that. Also I found the motor # F115TJR manufactured in 04/06.

[boscoe99]

Welcome.

Your model is fuel injected. The Primestart system within the computer adds extra fuel to facilitate a cold start. You won't hear a sound. Yamaha uses electrons in that model that are very quiet.

The motor uses various sensors to detect air temperature and engine block temperature. Based on inputs from these sensors the computer determines how much extra gasoline to add. Perhaps one of your sensors is not correctly telling the computer that it is cold.

[boscoe99]

Is the an out board engine with a jet drive? And is it 80 HP or 115, don't think it can both...There is no 80 HP listed for the US.. Where are you located?

Model #? Should be 3 or 4 letters..

2 or 4 stroke?

Which one of these?: 2006 and Later Yamaha Outboard Parts

A Yamaha jet drive outboard can be known as a 115/80. 115 for the horse power of the engine and the equivalent of 80 HP from the jet drive unit. Jet drives are fairly inefficient.

[Just like to fish]

Thanks for the reply and info, guess I need to figure out my next move for the fix.

[Just like to fish]

BOSCOE99,
So are you telling me that my ignition switch, push to choke actually does nothing for me because the computer just uses sensors to add the enrichner fuel when the sensors say the engine is cold.

[ausnoelm]

If your motor is EFI, then there is no choke, the switch will still push in, but it does nothing.

[robert graham]

Try pumping that black rubber primer bulb several times just before cold starts....it may help

[TownsendsFJR1300]

A Yamaha jet drive outboard can be known as a 115/80. 115 for the horse power of the engine and the equivalent of 80 HP from the jet drive unit. Jet drives are fairly inefficient.

Well that's very interesting...

A regular, say F150 doesn't give HP spec's at the prop (their not counting drive-line drag) un-like the above engine...

Agreed the jet drive is less efficient BUT I would think there's more HP loss on a propped engine. Drive shaft, LU, 90wt oil, etc vs non of that on the jet drive...

I guess (doesn't sound right) the jet pump takes MUCH more HP (equivalent to 35 HP??)

[boscoe99]

With a propeller driven outboard motor it is understood that the HP rating is at the propeller shaft.

With a jet drive outboard motor it is understood that the HP is at the jet pump.

Big big difference between the two.

Here is Yams lineup of jet drive motors. They make an effort to be clear that a jet drive F150 is not going to have anywhere near the thrust that a propeller driven F150 will have. Many in the past bought an F150 jet drive and were then disappointed with its thrust.

[boscoe99]

BOSCOE99,
So are you telling me that my ignition switch, push to choke actually does nothing for me because the computer just uses sensors to add the enrichner fuel when the sensors say the engine is cold.

Yes, even though your key switch may have a push-to-choke function, pushing the key does nothing with respect to a Yamaha motor that has PrimeStart, which is an automatic fuel enrichment system. Same key switch is used on different model Yams, some having a choke and many not having a choke.

You did not say what model motor you have. If it is a Yam USA model then it has got to be fuel injected since all F115's/80's have been fuel injected since 2001.

[TownsendsFJR1300]

You did not say what model motor you have. If it is a Yam USA model then it has got to be fuel injected since all F115's/80's have been fuel injected since 2001.

Post #4:

F115TJR manufactured in 04/06.


(Interesting about the output #'s.... thanks)

[DennisG01]

***, I didn't realize there was THAT much drop in HP!

EDIT: Apparently "w o w" is bad word on this forum!

For what it's worth, stern drive boat manufacturer's (Sea Ray, Chaparral, Bayliner, etc) USED to advertise HP the same way. They would advertise HP at the crank, not the prop. Sometimes they did both, but usually they just advertised the higher HP. Somewhere around the mid-90's they stopped doing that and now only advertise prop HP. Whether it was the engine manufacturer's choice, the boat manufacturer's choice, or some combo there of, I don't know.