Yamaha 225 ox66 rough idle

[rodbolt]

Re: Yamaha 225 ox66 rough idle

hello<br /> I hope they can fix it. if you unplug the knock sensor it usually will lock the timing,instantly at 7*BTDC. I saw a guy fall over doing this once and almost wet myself laughing. the RPM increase is about 1500 rpms and its instantaneous.<br /> good luck and keep posting<br /> PS please lose the caps. it hurts my new bi-focals

 

[sschoener]

Re: Yamaha 225 ox66 rough idle

rodbolt,<br />i just stopped by the marina and they think it needs a new vapor separator - are looking for a used one to test it with. they say the new part is $12oo. at this point i don't care i just want my boat to run

 

[rodbolt]

Re: Yamaha 225 ox66 rough idle

agghhhhhh<br /> now they are parts chunking<br /> run man<br /> run like hell<br /> your getting ready to get snorked.<br /> all the VST is is a gas tank<br /> it is a place to insure the high pressure pump can have a supply of clean bubble free gas. that way it can maintain 35psi on the fuel rail regardless of throttle setting or speed of opening. the vst contains the pressure regulator the needlevalve to maintain the proper fuel level and the high pressure pump. other than that its a large gas can on the side of the motor. its time you found a dealer that has some trouble shooting capeabilities on the water. the poke and hope method gets dang expensive on that motor.<br /> good luck and keep posting

 

[bruce537]

Re: Yamaha 225 ox66 rough idle

hello<br />I was just reading this post. 2 things I have found on my 1998 yamaha 225 ox66 is that like Rodbolt mentioned, that O2 sensor must be cleaned every 100 hrs or so, mine is almosy 100 hrs like clockwork, I can tell when it starts running rough and chugging that it is time to clean. I have 1200 hrs on my motor, at about 700 hrs, I bought a new O2 sensor so now I have 2. When I take one out I have a nice clean one to put in after decarbing with Deep Creep, a clean O2 sensor, running it, then changing the plugs.............it runs sooooooooo smooth it is truly amazing.<br />Also, before you go through a big process to check fuel problems when you are losing RPM's.check the resistor caps, they are a common problem and only 10$ a piece to replace. Check the resistance. Plug wire w/resistor should be approx 750-850. The coil w/out the resistor cap should be approx 350.<br />bruce

 

[sschoener]

Re: Yamaha 225 ox66 rough idle

rodbolt - yesterday i went to the marina and spoke to the mechanic. he has diagnosed a faulty fuel pressure regulator NOT a bad vapor separator - and they have ordered the part. hopefully i will have the boat back early next week. i feel better having talked to someone who is actually working on the boat. the communication at this place is abosolutely horrible. they have had the boat for eight days and to date no one has ever called me - i have had to initiate contact each time - each time getting either partial information or wrong information. theres is a lesson here somewhere in customer service. anyhow i'll keep you posted on the repair - the mechanic seemed very knowledgeable and straightforward - hopefully the guy who figures out the bill will be the same!!

 

[sschoener]

Re: Yamaha 225 ox66 rough idle

Rodbolt and Capt. Crunch - Thanks again for all your help. I got my boat back today and it runs really well. It turns out, it needed a fuel pressure regulator and new filters. It runs out perfectly all the way to 5500 rpm - It had not seen more than 5300 since I've owned it. <br />This experience has convinced me to do my own maintenance (with the help of the factory service manuals of course). It seems to me that the routine service performed so far with this motor has been inadequate so I will begin a more rigorous routine right away (including regular O2 sensor cleaning and biannual fuel filter replacement). I also have a 2003 90hp Yamaha on the boat I just purchased for my wife and I ordered the service manual for that as well. Again, thanks for all your help.