Yamaha 70hp rough idle

[Hawklakebenny]

My new boat has a rough idle, it's a new non- current 2013 model year 70 hp Yamaha. We have about 5.5 hrs on it now and it has not improved yet. Is this due to the more aggressive cam in the engine? Or might there be a need to have it serviced?

 

[cwag911]

Call your dealer.

 

[BigKahuna]

Was it sitting a long time before you bought it? Could be old crappy gas. Run out that tank and add a fuel injector cleaner/gas additive and fill up with fresh gas and see if it improves. Worth a shot.....

 

[Bamaman]

The Yamaha 70 hp is the same now as 2 years ago--no changes.  Chances are it's a fuel issue.  I cannot recall reading of any customer complaints on the 70 Yammie.

You might want to continue with your break in procedure (per factory directions) and regroup at the 20 hour mark--when the first oil change is done.

In the meantime, I suggest you run 100% gasoline in it and warm the engine up well prior to going out.  And don't forget to check the oil level before every use--looking for the oil level to "increase" on the dip stick.  At least that engine's not known to "make oil" like some of the larger Yamaha engines.

 

[SEMPERFI8387]

AND USE FUEL CONDITIONER in the fuel, ESPECIALLY if it's ethanol. Even non-ethanol should have additive unless you are running it every day or two. Boats sit on water (typically), and are maybe run once or twice a week on the weekend if lucky. Unlike a car typically driven everyday, the fuel (ethanol) just sits pulling moisture. Knock on wood, we have been using treatment for 7 years on two boats and have not had issues. We also change fuel/water separator every year.

 

[CTays]

Had a similar issue on my old pontoon with a new 2013 Yamaha 70 hp upgrade. It turned out to be the fuel line was pinched slightly the way the dealer had ran it from the tank to the motor. Ran fine after the line was replaced. He put a spring around the fuel line to prevent it from being pinched agian when turning the motor.