# 150 yamaha surging



## Brett (Jul 16, 2008)

Fuel feed would be my first guess.
Checked your plugs to see if you're running rich?


----------



## twitch (Mar 4, 2007)

I'd check the fuel pumps again. Unbolt them from the block and pump the primer, if any fuel comes out of the engine side of the pump the diaphragms are shot. A bad FP diaphragm can make you run rich at idle and lean on the top end, just as you described. [smiley=2cents.gif]


----------



## jeff_erickson (Jul 18, 2011)

Thanks, I think I will rebuild both pumps to be on the safe side. Cheap fix for a 2005 engine


----------



## jeff_erickson (Jul 18, 2011)

Do you think ethanol might have caused the trouble?


----------



## DuckNut (Apr 3, 2009)

Ethanol is not the root of all engine problems. Most likely it is the years of use that simply deteriorated the seals and gaskets.


----------



## twitch (Mar 4, 2007)

If you are running ethanol I'm sure it contributed, if in fact your fuel pumps were the source of your problems. ETOH is hard on rubber parts.


----------



## cutrunner (Jun 8, 2010)

Ok. If your fuel pump diaphrams are white, they are mylar and most likely your problem, the updated ones are black and made of neoprene. Or.. Another syptom of your problems is a stuck float or a "sink" (a float with a hole in it that doesnt, well float lol)


----------



## jeff_erickson (Jul 18, 2011)

I replaced both fuel pumps and it runs like new! Thanks


----------



## twitch (Mar 4, 2007)

Glad ya got it fixed.


----------

