Yamaha F225 Problem

[dduflo]

I have twin F225s that usually are flawless. Recntly, and then only very rarely, my starboard motor will act as if it is fuel starved. It drops RPMs and quits or runs rough at 300 RPMs. I have checked the engines fuel filters and changed the Racor water seperation filters. If I squeeze the fuel bulb once or twice the problem goes away. I put about 30 hours on them last week and it happened twice. Port engine runs fine. Both will turn up max RPMs at WOT. I'm buying fuel from a very busy marina and they have not had any reports of bad fuel. I talked to my mechanic about putting them on the shop computer and he said he didn't think it was necessary because the onboard computer would display any issues it couldn't correct on my guages. Engines have 455 hours and the water pumps were rebuilt this spring. Any suggestions?

 

[georgemjr]

Are you running both engines off of the same tank? Sounds like a slight fuel starvation problem, but doesn't make a lot of sense that it would only affect 1 engine, uless you were running off seperate tanks. Possibly VST filter getting clogged. Could start by running that engine off a seperate 6 gallon tank to see if problem goes away. If so, the problem is in your fuel supply. If not, in the engine. If the latter, start with the VST...

 

[seasick]

If pumping the bulb helps, it's either a blockage in the fuel feed or a bad low pressure pump. If there is a blockage in the fuel feed, the bulb should get soft or colapse when the problem occurs. If it doesn't, the LP pumps are the next logical place to look

 

[Grady678]

How do you differentiate shop computer from onboard computer. The onboard computer will help narrow down the problem immediately when hooked up to a Yamaha 'shop' laptop. If your mechanic is Yamaha certified.....I am missing something. 101 is hook up the computer for diagnosis.

 

[Lainie J]

I had a similar problem with my starboard engine in the spring. It would hesitate at around 3K and sputter. I changed all filters and it eventually corrected itself. Did you change the smalll filter under the flywheel cover? You have to take the black plastic cover off and its toward the front and top of the engine under a small rubber cover. My certified Yamaha guy aslo told be to check the plugs. Check for if they are good, a white plug means it is bad. I did that first and mine were all good. I then changed out all filters and problem went away.
Good luck.

 

[seasick]

I had a similar problem with my starboard engine in the spring. It would hesitate at around 3K and sputter. I changed all filters and it eventually corrected itself. Did you change the smalll filter under the flywheel cover? You have to take the black plastic cover off and its toward the front and top of the engine under a small rubber cover. My certified Yamaha guy aslo told be to check the plugs. Check for if they are good, a white plug means it is bad. I did that first and mine were all good. I then changed out all filters and problem went away.
Good luck.

If the filters between the motor and the primer are clogged, pumping the bulb shouldn't help but in his case it does. I would look elsewhere.