Yamaha 2004 115 HP 4 Stroke Troubles

[Catfish J]

I have a 2004 115 Hp Yamaha 4 Stroke. The engine seems to cut out like it is starving for fuel after running at 3/4 to full speed for a few minutes. The boat does not come off of plane it just seems to bog down and makes the boat jerk like you are hitting the brakes in a car. It will do it two to three times in a few seconds and then stop especially if I back off the throttle. I have changed the fuel filter and added Sea Foam to the gas. I am also slowly replacing with the fuel with non-ethanol gas as I burn the old gas out. Since putting in the Sea Foam it has gone from cutting out always to only at high speeds. Does anybody have any other suggestions on what to try. I am trying to keep from putting it in the shop and spending a lot of money. Thanks for all your help.

 

[99yam40]

Re: Yamaha 2004 115 HP 4 Stroke Troubles

monitor fuel pressures to see if they are dropping due to restrictions or maybe sucking air into fuel system due to leaking connections

 

[Capt Ken]

Re: Yamaha 2004 115 HP 4 Stroke Troubles

Listen to the rear of the engine with the cowling off. Does it sound like a lifter or valve ticking? Squeeze the primer bulb, does the ticking go away? If so then the fuel pump is not holding pressure.

 

[Catfish J]

Re: Yamaha 2004 115 HP 4 Stroke Troubles

Listen to the rear of the engine with the cowling off. Does it sound like a lifter or valve ticking? Squeeze the primer bulb, does the ticking go away? If so then the fuel pump is not holding pressure.

What will that sound like. When I was running in the boat I thought I heard what sounded like a high-pitched bell. Not a warning signal or anything just like light metal rattling against each other.

 

[Capt Ken]

Re: Yamaha 2004 115 HP 4 Stroke Troubles

You can do this in the drive while flushing. Just remove cowling and listen at the rear of the engine. Should be a ticking noise.

 

[multimech]

Re: Yamaha 2004 115 HP 4 Stroke Troubles

Since it gets better by adding Seafoam, I am going out on a limb and going to say it could be the carbs. Unless you know how to accurately clean a carb and synchronize them on a four stroke, leave it to a reputable dealer.

 

[Pas Bon]

Re: Yamaha 2004 115 HP 4 Stroke Troubles

Since it gets better by adding Seafoam, I am going out on a limb and going to say it could be the carbs. Unless you know how to accurately clean a carb and synchronize them on a four stroke, leave it to a reputable dealer.

That motor is Fuel Injected

 

[Mfulfer]

Re: Yamaha 2004 115 HP 4 Stroke Troubles

I am with Capt Ken. Sounds like fuel to me. first things first take a sample of what you engine has been trying to run. there should be a hose coming off your VST. (that would be the metal thing that is behind the intake) the hose should be pink and cliped to the intake. it will lead to the vst and there you will find a brass screw...crack it lose a that will give you a sample. what does to look like is it filled with crap. if so you may have a clogged high pressure fuel filter