93 yamaha 130hp help

[baseball2828]

Ok guys need some help here. This is my 1st hi performance boat so be gentle. Right now Im scared to death. 93 Yamaha 130hp V4 last cpl times out it started and sounded "muffled" but idled ok, when I throw the throttle to it, it would turn about 2400rpms and sound like it was "hung" did this for about 10min with me on and off the throttle, then after awhile it would take off and run like a scalded dog the rest of the day. It would hesitate a bit on take off but other than that ran good. Any help? suggestions? diagnosis? Thanks

[Reata210]

I owned a 92 Yamaha 130 for 16 years. I would check and make sure the fuel from the tank is not restricted from the check valve and that fuel is not contaminated with water. When it starts acting up is the primer bulb firm, soft or collapsed? Check the filter and clean the screen on the filter under the cowl. Sounds to me like water in fuel. You may want to also install a 10 micron filter/water separator. The carbs may need rebuilt as well although being an intermittent problem that is less suspect. My guess with out looking at it would be fuel delivery or water contamination.

If you’re running e-10 (10% ethanol) I would change out all old fuel lines with new fuel lines rated for ethanol. This could be a problem as well on an older boat.

Once you rule out fuel delivery I would check compression in all cylinders, in fact you may want to check this first.

Could be ignition as well or your losing a cylinder. Check to make sure your not getting intermittent firing on any of the four cylinders during drops in RPM.

PS: I would also recommend you start using ring free in every tank and change the plugs. Could be a fouled plug as well but being intermittent makes that less suspect as well.

Good Luck

[baseball2828]

thanks reata. I went out this morning and she ran ok other than the slight hesitation but she started good and 1st time i threw the throttle she took off. I put gas in yesterday and a bottle of seafoam.