 Help my Yamaha F225 is killing me... Grounded for Memorial Day weekend!
Re-posted from the main forum:
I hope there's some expert that might suggest a diagnosis from the description. Sorry for the long post, but I really need some help. Dealer can't seem to fix this thing and I missed about 8 weeks last summer and now starting off this summer on dry land again.
There's some history with this motor, but first the current status:
2005 Yamaha F225 with 398 hours. Winterized and stored until April.
Started up after the winter. Idled just fine. Dropped it into the water and idled out of the harbor, tried to power up and it just stumbled, misfired, and wouldn't rev past 2500. Woudn't get on plane. Idled back into the dock and back onto the trailer she goes. Yamaha dealer ran it on the hose and did miscellaneous tests. Looked for scan codes. Checked injectors. Filters are clear (and new). 100 gallons of fresh fuel a few weeks ago. The 25 gallons that remained in the tank from last fall were treated with Stabil, Ringfree, and Startron. Plugs are new and perfectly clean.
Dealer couldn't find anything wrong, and said it ran fine on the hose. Couldn't find the time to do an in-water test before the big weekend. So I took it home, hoping the mysterious problem went away. Ran it in my driveway and had the exact same problem. Stumbling, misfiring, and won't rev up. And now the idle has become rough. I have no idea why it didn't perform this way in the dealer's yard. I ran a gallon of fresh gas and a can of Seafoam through it and it did not help in the least. Incidentally, there was virtually no smoke from doing this so this would seem to indicate my engine is very clean.
I mentioned there was some history. Here it is:
Last season, boat was dead in the slip one Saturday. Brought it in to the same dealer. VST and both external filters were replaced, and the low pressure fuel pump was dead and was replaced. It ran fine for one day. Then next time I tried to run it, the fuel pump was dead again. Replaced the pump again. And pumped out the remaining 20 gallons of fuel. Replaced with 125 fresh gallons, along with Startron and Ringfree. Incidentally, there was never any verification of phase separation or contamination. So Yamaha covered most of this under warranty. (except for the filter changes).
Finally I get the boat back last September and the low pressure fuel pump finally continues to work properly. But the motor never ran perfectly after that. Rough idle, slight hesitation, and I lost about 500 rpms on the top end. But it ran just okay and I put about 20 more hours on it. Back to the dealer in October, they finally diagnosed my problem as 2 clogged injectors. They were replaced under warranty and I picked the boat up. It was now mid November and time to put her away for the winter. I expected everything to be perfect in the spring. Unfortunately that is not the case. The problem is even worse. I can't run the boat at all.
Any ideas? Any of this sound familiar. My dealer and the Yamaha factory tech have both been great in terms of trying hard, communicating, and putting in the effort. And covering the majority under warranty. But I'm missing the summer again. Help! Anyone.....
I had a random thought that the high pressure fuel pump may be failing. I'm not an expert, but this sounds plausible. Although I'm pretty sure my dealer has used the proper test equipment to test that.
I welcome your input. I'm on the ground all weekend and maybe longer... | 
