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Results 1 to 13 of 13
  1. #1

    Default 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    New to forum so sorry if this is been addressed in past.* I need advice.

    I have 2003 Yamaha*200 HP OX66 EFI that has never given me a problem.* I bought it new.* Has had 100 hr checkup every spring since new at reputable dealer.* Very well maintained, has 527 hours.* Last spring (2011), I started having slight hard start rough idle after running to fishing spot and turning off engine for 10-45 minutes.**This would continued all day on a trip but didn't seem too bad as*problem was minor and would clear up within 5-10 seconds after starting.* Engine would then be perfect....idle great, run great, up to 6000 rpm's, just like new.* Come off*to idle at next spot and idle 700-800 rpm, just perfect until I turned engine off and sat for some period of time, then slight hard start again, but quick clear up.* Used it all last year and was just a minor irratant.* Put about 75 hours on engine since it started doing this.* In January/Febuary this year, it seemed like this problem seemed to get a little worse....still cleared up quick after warm start, but sometimes had to advance throttle to get started, and engine would idle rougher and smoke quite a bit for first 10 seconds after hard start.*Would*idle at 300-400 rpms while rough idle until it cleared up and idled fine at 700-800 rpms*within 10 or so seconds.* Still, after it cleared up, all great....good idle and runs great at all speeds.* If I stopped and tried restarting immediately, idle was great.* Only after engine was off for a while did I have hard start.

    So....I took it in 2 weeks ago to dealer for 100 hr maintenance and asked for them to also fix this problem.* They have replaced all filters (water sep, filter on side of engine), spark plugs, cleaned O2 sensor, etc.* Lake tested and duplicted hard start problem.* They checked compression (said it was perfect), checked fuel pressure (36 psi while running and 28 psi and holding after turning off engine), check all electrical components and couldn't find anything.* They finally pulled a hose on top of Vapor Seperator and found fuel coming out.**Opened up VST and found needle valve worn out.* They were convinced that was problem.* Replaced needle valve and cleaned out VST and lake tested.* Guess what....warm hard start was still a problem.* They called Yamaha and Yamaha said it was "winter fuel mix".* Impossible as I have run at least 15 tanks*of gas since last spring.* Current gas*was put in within last month, so it is running on fresh fuel.* Dealer is stumped.* They are not ready to give up, but*I took boat last week and ran it to see if it is any better.* I put in double dose of Ring Free and ran it all day on Friday.* Ran thru about 25 gallons of gas and the problem still exists, just like before. Engine is perfect except hard start rough idle when warm.*

    So....HELP...what could I be missing?* Still smokes*more than*normal when first started warm until it clears up in 10 or so seconds.* I think*I am too rich at start.* Could I be getting gas leaking into manifold or cylinders after I turn engine off?* Could this be a primer bulb issue (this is original bulb).* I have never had to pump it since I have owned the boat.* Always started within 1-2 seconds without ever pumping it even after sitting a month.* Checked bulb throughout day on Friday and it never seemed to get really hard when pumped.* Actually, I pumped it a bunch before one start, and it seemed to make the start even harder.* Or, could I have a pin hole in one of my fuel pump bladders? said my pressure held at 28 psi after turning the engine off.* Not sure how long they waited.* What else could it be?* I like things right, so it's hard for me to just accept that I will have to live with this.* Remember....if I wait a*week and walk up to my engine and turn the starts great immediately with good idle rpms.* Seems like if the gas in dumping, then it has time to evaporate over time and give me a good cold start.

    You can tell I am frustrated....appeciate any incite on this.* Sorry for the long verbage, but wanted to get complete info to everyone so as to get the best most accurate response.**

    I **

  2. #2
    Join Date
    May 2011

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    Good info. Start with the simple things. Have your fuel pumps ever been changed? If not it is time.

  3. #3

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    Thanks....I will be at the bay house on Monday, and will replace them and give it a go. I believe fuel is dumping when warm, so a pin hole in one of the bladders makes sense. Hope it is that easy. We seem to have checked everything else.

  4. #4
    Join Date
    May 2011

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    Those lift pumps aren't reliable after 350 hrs in my opinion so it is good PM to change them out regularily. Also if pumping the primer is causing a drop in idle rpm you can assume that the pumps are leaking into the crankcase. The winter fuel blend is also a valid diagnosis if that is what your distributor is still pumping.

  5. #5

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    PBR...thanks for the additional input. Didn't think to pump the priming bulb while running....such a simply test!! I will try it first. Don't think it is winter fuel blend, as this started a year ago (spring 11), so I have probably run motor at least 60 hours since then with this problem, so probably 10 tanks of gas (60 gal tank) since then with most hours from April-October. Problem has been consistent through out the full year. I run regular fuel (87) all bought from the same Exxon station since I bought the boat in 2003. I was told by my dealer and tech that yamaha fuel lines are silicone based and are not affected by Ethanol. Can anyone confirm this....I originally thought I might need to change out my fuel lines, but shop said no....they could have easily sold me that repair.....but didn't?

  6. #6

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    WLS... I have a 2001 Yamaha 225 OX66 and have been experiencing the same exact problem for over a year. My fuel is fresh and mostly Ethanol free. Also treat with Stabil. Took boat into the shop last year with no definitive answers. They called Yamaha and were not able to get an answer there either. Shop thinks may be one of the temperature sensors or oxygen sensor. Going to start with the temperature sensors. Please post if you are able to find a solution on your end.

  7. #7

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    I feel your pain....frustrating when you can't identify or toubleshoot a problem. I am going to work on mine the next few days (LP fuel pumps) and will report back. The shop cleaned my O2 sensor, so I don't think that is the problem. This seems to be such a common problem that someone should know the solution easily........

  8. #8

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    You may be on the right track. After searching the internet for an hour I found the following on Several had the same experience. I am going to return the Temp Sensor $60 and opt for the 3 new pumps $120 for the parts changing.

    Re: Hard to start VMax 225 when warm (Cajun Skeeter)
    My 225 V-max (ox66) motor did the same thing. Changed the plugs, cleaned the O2 sensor, changed the inline fuel filter (water seperator-you really need one of these), changed the filter on the side of the motor, changed the filter in the vapor canister and it still was hard to start when it was warm. Read about the 3 mechanical fuel pumps on the side of the motor and the problems they can cause when a diaphram starts to leak. Went to Yamaha dealer and bought three new pumps ($35 ea) put them on and it starts on the first turn when it's warm. Just a suggestion for you.

  9. #9

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    Blazer....good find. I'm optimistic this will solve my problem, but who knows. I will report back by Wednesday evening.

  10. #10

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    UPDATE!! Problem solved! Replaced all 3 LP fuel pumps and problem solved. Took the old ones apart to see if I could figure out which one was leaking and one had a bulge on the bladder, but no obvious hole. When I took them off, I looked for a sign of leaking from the hole on the back, but none present. Ran on the bay for 8 hours yesterday (probably 30 warm starts plus used 20 gallons of fuel) and started perfect within a second every time. 800 rpms...perfect. Plus I caught fish!
    As a side note, came back to Houston today and stopped by the dealer and talked to the owner and Tech who worked on this problem 2 weeks ago....both said they knew the test procedure and had disconnected the pumps and pumped the primer bulb to test them. No leakage was noted so they moved to the next possible cause. They figure the hole must have been small. Known them (and trust them) since I bought the boat from them 9 years ago. Owner will give me $100 credit on next repair, and was very sorry they didn't fix it when it was in.

    FYI, before I replaced them, I started the motor, let it warm up, and pumped the primer bulb hard. Didn't lose any RPM's, so that doesn't always work.

    Finally a solution to a problem I have had for over a year. Thanks, PBRMAN....I owe you one!

  11. #11
    Join Date
    May 2011

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    Here is the easy way. Identify the parts that wear out and replace them on a schedule. To whomever may care, "Preventive maintenance is a way of scheduling your down time", Charles Walther.

  12. #12
    Join Date
    Sep 2010
    Jersey Shore

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    FYI, keep a spare set of pumps available. This is a common problem and with ethanol in the fuel it has become a frequent problem.
    Dockside Marine Services
    Jersey Shore.
    Let the insanity begin.

  13. #13

    Default Re: 2003 OX66 VX200B Hard Start Rough Idle when warm HELP

    Thanks for the follow up and glad to hear your problem is solved. I changed my 3 LP Fuel Pumps today. 2 of mine were leaking using the primer bulb test. One was leaking so bad if you blow on the in port with your mouth, covering the out port, air would escape out from the hole in the back. I have not run the boat yet, but feel pretty confident this will fix my problem as well. Regardless some PM has been performed.

    Thanks wlspathfinder and pbrman for creating this forum.

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