# Help with Yamaha F90 fuel delivery



## Native Son (Oct 4, 2012)

I have a 2008 yamaha F90 bought new and put on a 17ft Boston Whaler in the spring of 2009.The boat only gets used about 6 to 8 times a year. We had to replace the fuel pump in April of 2012. We ONLY use ethanol free gasoline. Well I went to get the boat ready to take out this weekend and the usually very reliable motor wouldn't crank. We noticed the primer bulb wasn't hard so assumed it was a simple fuel delivery problem from the tank to the motor. I replaced the bulb and that didn't help. 

So, here is what else I have done:

1) started at the fuel tank checking the siphon tube for a clog ~nothing
2) moved on to the bulb and disconnected the downstream hose to insure the bulb was pumping fuel ~ it was 
3) I re-connected the downstream hose to the bulb and removed the fuel/water seperator to make sure there was not any air in the separator ~ there wasn't' it was full of fuel
4) While the fuel/water separator was off, I again pumped the bulb to insure fuel was making it to the fuel/water separator ~ it was
5)Put the fuel/water separator back on and moved on to the motor
6) Removed the fuel reservoir that has the water/fuel alarm in it , emptied the fuel out of the reservoir and manually tested to make sure the alarm sensor was working ~ it was
7) put the empty reservoir back on the motor and pumped the bulb. The reservoir filled back up with fuel


So, is it possible that the fuel pump has gone out again in a little over a year with minimal use? Is there something I haven't checked? If the fuel pump has gone out again what more can I do to prevent this from happening. The pump itself is a $350.00 part plus labor. No way these pumps are meant to be replaced this often.

Thanks in advance for any help guys.


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## TheCaptKen (Mar 14, 2011)

Turn the key and listen for the high pressure pump to hum. If it does, find the schrader valve on the top and press the valve like you would a car tire and see if there is pressure.

Before all that, the kill lanyard is clipped in isn't it?


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## Native Son (Oct 4, 2012)

Yeah, the kill switch is definitely plugged in. If I pump the bulb non-stop for say 1 min, then when I turn the key the engine starts to turn over and then stops. Almost like it is getting just a small amount of fuel and once that is burned off it doesn't get anymore. I will try the schrader valve.

Thnx CaptnKen!!


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## TheCaptKen (Mar 14, 2011)

I would bet your high pressure pump isn't working or water in the fuel.


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## Flounderpounder (Oct 3, 2007)

I never even had to touch the bulb w/my 90F!! Sounds like you may be onto something with the pump/valve? If that doesn't work, you might check the tank/lines and filter etc by using the shortest line you can from the motor into a 5 gallon (or smaller) jug (bypassing the rest of the fuel system). This worked for me once.....apparently an interior piece of fuel line separated, causing a flap/obstruction. New piece of line.....she ran like new! Good luck tracking down your gremlin! Like Ken said.could be H20 as well...you need to fish more!!!!


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