Yamaha 115 two stroke / 2001 surged at 1/4 throtle.

[17footter]

Hi. I'm new here. I have a 2001 115 Yamaha 2 stroke on 174 sailfish boat with 200 hours in salt water. Lately, the motor is having problem bogging down from idle to ~ 2000 rpm for several seconds, then just like turn on a switch, it picks up and run as normal.( Max out at 5500 rpm ). already take the carbs apart to clean twice. add Racor filter won't help either. I really thanks in advance for any info.

 

[Ray Neudecker]

Re: Yamaha 115 two stroke / 2001 surged at 1/4 throtle.

You obviously have a fuel restriction problem. Replacing the fuel pump would be in order since it is a maintence item. Doing a flow test on the carbs would also be in order.

 

[17footter]

Re: Yamaha 115 two stroke / 2001 surged at 1/4 throtle.

Thanks Ray. I did just that. Disassemble the old pump and found a pin hole in the diaphragm. It probably flooded the spart plugs at idle speed. As your advice, change a new fuel pump, the motor is back to normal at the afternoon run. Thanks again.

 

[Ray Neudecker]

Re: Yamaha 115 two stroke / 2001 surged at 1/4 throtle.

Glad you got it fixed. Happy boating.