90 Yamaha 115

[Bozo]

My 90 Yamaha 115 has a tough time starting when it has not been used after a day or two. <br /><br />I have to crank it for 30-40 seconds straight to get it to hit/fire with the manual choke engaged. (even though I have verified the electric choke is working, it just doesn't cut it for some reason) <br /><br />Once it hits/fires, mind you it isn't running at this point, I have to go back to the motor and disengage the manual choke and start it with out any choke at all. Then and only then will it fire and run. The rest of the day it is fine and dandy without a problem.<br /><br />I am thinking that it may be the fuel pump diaphram that is weak and not reall pumping hard enough to prime the carbs. <br /><br />Any thoughts?

 

[rickdb1boat]

Re: 90 Yamaha 115

Bozo<br />Next time before you try to start her, give the Carbs. a shot of premix in each one and see if it pops right off. Also, are you pumping up the primer bulb before you try to start it? Does it pump up and stay firm? I would also get the electric choke repaired, if defective.

 

[Bozo]

Re: 90 Yamaha 115

The electric choke is working, meaning that it closes the butterflys when activated but, for some reason it just seems to fire up quicker if I use the manual choke. <br /><br />Additionally, yes I am making sure the primer bulb is pumped up nice and firm. <br /><br />I will try the premix idea the next time.<br /><br />If it does kick off right away after that, am I on the right path with the fuel pump diaphram?

 

[rickdb1boat]

Re: 90 Yamaha 115

I doubt that it would make a difference on start-up. Make sure your choke plates are closing all the way first. Also if it runs good after that, it's not the pump.

 

[Bozo]

Re: 90 Yamaha 115

Yeah...it runs good after that. My line of thought was that it seems to smoke quite a bit after it first starts for about 30 seconds and was thinking that it may not be getting the right amount of gas.

 

[Bozo]

Re: 90 Yamaha 115

Let me throw this in as well.<br /><br />I have a repair manual for this motor and it indicates that the adjustment screw on the carbs needs to be set at "5/6" . I interpreted this to mean that would be approx. half a turn from bottoming out or five sixths of a turn.<br /><br />I rebuilt the carbs and set the adjustment screw to "5/6" and the motor would work for crap. I ended up adjusting the screw to around 2 complete turns from the bottom out and it runs fine other than the hard to start problem.(I adjusted each carb identically) It idles at around 900 rpm out of gear and 600 in gear.<br /><br />Did I interperet the adjustment setting wrong or what?<br /><br />Does anybody have a repair manual that says anything different?<br /><br />Thanks,<br /><br />Bozo

 

[Bozo]

Re: 90 Yamaha 115

Oh yeah, it has the two bowl carbs. <br /><br />Thanks again for any assistance.

 

[bret walters]

Re: 90 Yamaha 115

reclean the carbs, yamaha carbs are very sensitive to fouling. they needed to be soaked a dip type carb cleaner. buy the strongest type you can find ( napa has a good one), the carbs must be completely disassembled first, soak for at least 2 hrs. then rinse with hot water and blow dry with compressed air making sure every passage is clear. reinstall and perform sync. and link exactly from service manual. adjust electric choke to completely close when activated. clean all battery cable connections? yes battery cable terminals, if loose will cause large voltage drop when starter is engaged and choke soleniod will not keep choke plates closed when cranking. check this first by cranking with airbox cover removed and obseving choke plates, thy should stay closed until you release key switch.

 

[Bozo]

Re: 90 Yamaha 115

The choke selonoid on this motor is attached to the airbox. It is not possible to see how the butterfly is working with the airbox on and is impossible to operate the choke with the airbox off.<br /><br />I will look and see if there is an adjustment for the choke and make sure I close it a little if there is.<br /><br />I have a gallon of the beremans(sp?) Chem-dip that I used the last time. I will try to soak them again and see if there is something that I missed. You are right though, I do remember that it started very quickly when I installed the carbs after cleaning them with the muffs on so that I could adjust the idle mixture setting.

 

[Capt Ken]

Re: 90 Yamaha 115

Bozo, you mixing this one up with an OMC. Yamaha's choke solenoid is attached to the starboard side of the intake manifold.

 

[Bozo]

Re: 90 Yamaha 115

This model is a Yamaha and the selonoid is mounted to the black plastic airbox. If you are looking at the carb side of the motor, the selonoid is mounted on the left side of the air box on the back side closest to the carbs. The wiring runs across the top of the airbox to the right side of the motor and the actuator arm extends in a downward direction and attaches to the carbs. when the choke is activated the arm retracts, raising the actuator arm and engaging the choke. <br /><br />The wires have quick connectos built in because you have to unplug them to get the airbox off in addition to removing the actuator arm from the carbs.<br /><br />I have had the carbs off 3 times, that is why I know that the selonoid is attached to the airbox and not the side of the motor. <br /><br />The Yamaha airbox is a solid one piece unit that completely covers the front side the motor and makes it impossible to see exactly how well the electric choke operates.<br /><br />Thanks for the response, I hope that with enough folks thinking about it I can get this fixed.<br />All suggestions and help is much appreciated.<br /><br />Actually, it works, just not as good as I want it to.