Yamaha 25 Cutting out

Motor ran great on the lagoon all day. Take it to the lake for a quick run/flush on the way in to the ramp about 3/4 to full throttle the motor dies instantly. Takes a few cranks to get it started and does the same thing. Got it started and motored half throttle back to the ramp. Any ideas? High speed jets clogged. Its a two stroke 05 model. The motor acted as if I had hit something but the area was clear and it happened again once I throttled up. Seems odd that a motor would suddenly die at high rpms... Thx

 

Primer ball was still primed. I checked that and the vent first. The motor was ran for several miles that day with no issues. Thats what has me stumped. The fuel was only a day old and non ethenol has always been used. Im the second owner of the motor and probably should start with a carb rebuild. It has been having idle issues and sometimes I have to idle up a little to keep the motor from stalling....

 

Spoke with a mechanic this afternoon and after examining the last chance filter, it appears my fuel line is breaking down. It's the older grey mercury line with the plastic liner so I replaced with new blue lines and primer bulb. After I split the old line in two I was shocked. Not a very good design and apparently they have had a lot of issues with them.

 

I ended up getting 20 ft. My tank is mounted in the front so I'm not sure of your length. Best thing to do is remove your old lines and measure. As far as what type to get, I just went to a boat shop and got the blue ethenol resistant at about $3 a foot and a new primer ball at $30. Shouldn't have any issues now and I highly recommend that if you do have the mercury gray line then to replace. Take it off a fitting and slice it in half and tell me what you see...

 

Heres some pics to show you what breaks down. If you notice, the last 1/2" of the plastic lining is gone at the fuel connector. It ended up in the filter.





This is the line I used to replace. It is 5/16" and fits nice and snug on a 3/8" barb connector. No need for clamps, I just used zip ties...

 

Took the yamaha out today and Presto!!! Ran like a champ.. Made sense that the liner in the fuel line would collapse under high fuel demand. I guess that's why it is nice to have an honest mechanic on your side