Trouble with a 2005 Yamaha 225 hpdi

Anyone now what the problem could be with my 2005 yamaha 225hpdi it seems like when I'm sitting in idle that the RPM's slowly drop then it will finally die. Then after it does this it is hard to start I have to wait a minute or so then it will start fine. Only way I can get around it starting sooner as when I'm cranking the motor it will try to fire but won't start unless I put it in gear while I'm trying to start it. This will only happen though about every 6th start of the boat it doesn't do this all the time. Also it seems like it is loosing some of it's top end speed. Before this problem boat would top out around 72-73mph now it struggles to hit 68mph. Also seems a little sluggish coming out of the hole. But when the boat is running above idle speed though the boat runs great. I have changed the spark plugs, air filter, ran a diagnostics test but nothing has seem to work. Any help at all would be greatly appreciated thanks in advance.

Air filter? What air filter? What diagnostic test did you run? How is it able to start in gear? There is a kill switch that activates if in F or R?? Sounds like that is a problem as well. Could be contaminated fuel, or problems with the injectors, or you may need the high pressure filter changed as well. If you don't have one installed I would also run a 10 micron fuel/water separator filter between the tank and primer bulb. Once all filters have been changed and you’re sure the fuel is good, it might be time to seek professional help. Good Luck.

The fuel is good I have ran about 4 tanks of gas in it since this started happening. As for the diagnostics check I took it to a dealership and hooked up to the computer to see if it has thrown any codes and it had not. As for the air filter they told me it was one that needed to be replaced once a year so they did, not for sure on what kind it actually is. I think it was the High Pressure filter that you stated. As for starting in gear I ment as I'm cranking it as it is in neutral you can hear the motor start to fire and when you hear it doing this you can put it into gear real quick and it will stay running but if you keep cranking it and not put it in gear it won't completly turn over and start. As for the injectors the dealership told they checked each of those and said they all were good. As for the 10micron fuel water sperator what kind would you recommend for that? Thanks for the help

pull a plug and see what they are doing. Also is your primer bulb hard when pumped.

Your dealer can only test the injector only to see if it’s operational. Dealers can not tell you the amount fuel an injector is flowing at different rpm levels. We flow test, clean injectors and will tell you if your injector is lean, within specs or if is flooding. No other injector service shop uses our method of testing and cleaning. We do not utilize an automotive type machine as all other shops do. If you want your injectors flow tested and cleaned visit Brucatosvs.com for all necessary information. You will receive a flow test report for each individual injector and the amount each injector is flowing on idle part throttle and at 6000rpm. With added ethanol in fuel we recommend this service at least once a year.
I would seek another dealer to fix your other problems. My guess is that your shift interrupt switch is bad. And your high pressure pump filter in VST only needs to be cleaned once a year, not replaced.

The plugs are good I replaced them twice, but when this engine starting problem happens (every 6-12 starts on the motor) that they get a fuel and oil mixture on them like the may be getting to much but the engine is not starting when this happens to clean them off but when the engine is running and I check them after that they are clean as a wistle. As for the injector testing that you were speaking of I will look into that but hard to drive to your shop when your in NC and im in MO (gas prices) LOL. The shift interupter switch what is that exactly? Thanks for the help everyone.

When was the last time you replaced your fuel pumps. Maybe a pinched fuel line. I don't know for sure just trying to help you out.

All our customers ship their injectors to us so no driving is necessary http://www.bassboatcentral.com/smileys/Laugh.gif . Right now we have a 3 to 4 day turn around time. As previously suggested check low pressure fuel pumps. They will flood your engine. They work of an engine pulses and if diaphragms are torn they will leak fuel into the crankcase and cause plug fouling, rough idle and possible engine shut down at higher rpm. This just happened to mine over the weekend.
Shift interrupt switch can be activated by poor engine performance (vibration) or lower unit problems. This switch is located next to the shift rail linkage and is design to cut out 2 cylinders while shifting in or out of gear.

Rich Z this switch should put a code in the computer if it is bad or not working the way it should.

Check your cables right in front of the motor. There is a latch that holes the cables in place, it may have opened up or just holding the cables tight at all times.

Yeah, I know. That’s why I suggested he should seek another dealer. I can’t believe people come here for answers AFTER they spend $$$ and time at dealers that can’t diagnose simple problems. One thing I noticed about hpdis is that some can be little temperamental with starting. At first crank up; prime the bulb, tilt the motor a little to reduce back pressure, turn the key to run for 5 sec or until fuel pump completed charging the system and then crank. BTW, how old and what condition is that cranking battery?

Hey Rich I guess I was assumeing

Hey Rich I guess I was assuming the dealer knew what he was doing but with some to the dealer out there like the one I just had look at my motor did not even know it had such a switch!!