787 RFI Problems
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  1. #1
    PWCToday Newbie srcpaint's Avatar
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    787 RFI Problems

    I have a 04 3D when you floor it it shudders and has no power, it does start right up normal when you go to take off it doesnot sound good, i replaced the plugs and made a lap aroung the lake, when i pulled the plugs the cerimic was still white on both plugs, you but could tell they had been fireing, it seem to me that it not getting enough fuel, but I don't know what to do now

    any advice?

    Thanks

  2. #2
    PWCToday.com Is My Home Away From Home Mr. Bill's Avatar
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    Re: 787 RFI Problems

    Replace the rectifier.

  3. #3
    PWCToday Newbie srcpaint's Avatar
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    Re: 787 RFI Problems

    Bill, I replaced the rectifer last year when the ski was not holding a charge, I just tryed disconnecting the rectifier and it ran the same, i also tried the old rectifier(the one that the ski would not charge with, and it still ran the same,

  4. #4
    PWCToday.com Is My Home Away From Home Mr. Bill's Avatar
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    Re: 787 RFI Problems

    It would be normal that the sparkplugs take awhile before they start to gain color, usually about 20-30 minutes or so, and fuel injection was designed to run cleaner and leaner than carbureated motors ( if not, what is the point of FI ? ) so that even takes longest to color-up sparkplugs.
    What you describe can be a few things, from a malfunctioning rectifier ( most common problem ) to using the wrong sparkplugs and many many other things.
    What we do not hear from most people when they tell us their problems or symptoms is information that might be pertenent.
    Ok you swapped out a possible bad rectifier for another known to be bad rectifier, big surprize ! It did not run better. Did you think it would ? What did you learn ? Nada.
    Put a voltage meter onto the battery before starting motor. What does it read ? Now, test that battery again at 3500 or above rpm. What does it read now ? This will tell you something, and at least answer the question of the charging system and wether or not, you, like so many before you, found out that swapping rectifiers yearly may be necessary unless you wise up and install a better rectifier like those used on the 4 tec motors. How long a rectifier lasts in an RFI has alot to do with how well you maintain a battery during the time the pwc is parked, as well as the overall quality of the battery you have. An RFI, unlike any carbureated model, relies on the state of the battery and charging system about 100% more than the carb models, with that high draw electric fuel pump motor, ECU, EMS, and overly complex double ignition module that costs $1900.00 to replace, about triple the price of a carb model's MPEM system. Carbs use a mechanical fuel pump. I would not even think of installing a battery back into an RFI unless it pulls at least a minimum of 90% or better on a load test of the battery. Anything less puts alot of work on the rectifier and regulator. Have you ever noticed that the RFI rectifier is not mounted inside any box and it has cooling fins on it ? You only see that in FI models. Now, ask yourtself why is that ?
    The 4 tec engines rely on tons of battery power to run them as like your RFI, it has lot's of extra electronics, a heavy duty electric fuel pump, sensors on everything except the rider's heart beat, then add in solenoids to activate high pressure air injectors, rave valves, well you get the gist...........
    Typical pwc owners only buy a battery when the old one no longer turns the starter motor, never pull them and put onto a tender when stored over the winter, check fluid levels on wet cell batteries, nor do they do a yearly spring battery load test to understand just how good their current battery's condition is. Nope, at best they throw a charger on it and when the battery will crank the engine and start it, they assume they are "good to go"......... Next stop, parts dept and a new rectifier, recharge that 75% battery, and everything runs good again for awhile. Then it no longer runs good and they say "it can't be a bad rectifier, I just bought one last year ".

    See why I have to go there first ? How many of the steps above did you skip during storage and getting it ready for a new season ?

    Next question. Did you put the new sparkplugs side by side with the orginal BR8ES's and check to be sure they were the correct sparkplugs ? Did you gap them to spec ? or assume they came gapped ? Beings that carb models use the same 'plugs as an RFI uses, did you assume the gap is the same for both and the NGK gapping is right for either model ? Never hurts to look up the spec and check the sparkplugs, as who knows, maybe the machine packaging them smashed the gap shut a bit, or someone dropped the box on the floor.

    Is your engine clyinder compression the same in both clyinders ?

    Was the hull or the motor swamped at all, or take in a big gulp of water, possibly snapping off a reed petal ? Or getting water into an electrical box like at the coil box ?

    How about fuel pressure? Up to snuff ? Anybody ever put a new fuel filter in the boat ? Does the fuel regulator work as it should ? How clean are the fuel injectors ? Got any water laying in the bottom of the gas tank ? How clean is the bottom screen on the fuel baffel/fuel pump ?
    Got any error codes showing up on the digital readout information center guage ? All sensors functioning properly ?

    Ever do anything like install a new throttle cable, or turn any adjusters on the throttle body or throttle cable ?

    Novi is far enough away from salt water, but I have to ask, you venture to Lake Michigan at all ?

    Bill
    Last edited by Mr. Bill; 06-28-2010 at 08:08 PM.

  5. #5
    PWCToday Newbie srcpaint's Avatar
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    Re: 787 RFI Problems

    I took the ski up to the seadoo dealer and had them hook it up to the computer and they said it was not blowing any codes, they also said it had 190 compression? How could that even be possible? This is a completely stock boat, i opened the head and everything looked great and cleaned the raves(they needed it bad) the dealer did not have the right equipment to check the fuel pressure, now it is acting funny even recognizing the dess key, if i leave it on there for a minute sometimes it will find it, and some times i have to pull the main fuse and put it back in. also some times the bilge still wants to run with the key out, now that it's out of the water, if i just rev it quickly it sounds OK, if I try to hold it as like 3000 rpm it sounds like crap

    as allways thanks for you help

  6. #6
    PWCToday Newbie srcpaint's Avatar
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    Re: 787 RFI Problems

    Bill, i found a bad connection, and now am not haveing trouble with the key, i did put a meter on the battery with the motor running, and the voltage jumped up to 12 something, also it seems like the maching actually runs better with the spark plug cover off of the rear plug

  7. #7
    PWCToday.com Is My Home Away From Home Mr. Bill's Avatar
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    Re: 787 RFI Problems

    Disconnect the bilge pump incase it is shorted out or has a stuck float switch in it.

    I asked you to see what the voltage in the battery was BEFORE starting the motor, so what was it?
    You say it jumped to 12 something. 12 what ? 12.1 ? or 12.9?
    A fully charged 12 VDC new battery holds 13.1 Vdc.

    Bill

  8. #8
    PWCToday Newbie srcpaint's Avatar
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    Re: 787 RFI Problems

    the battery was at 11.9 when i started, and it went to 12.4-12.6

    sorry, my bad

  9. #9
    PWCToday.com Is My Home Away From Home Mr. Bill's Avatar
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    Re: 787 RFI Problems

    Then remove that battery and charge it on a slow charge overnite, no more than 2 amps charging rate with a fluid filled battery to the top line on the battery case ( distilled water only if you need to add fluid ).
    Get up the next day and take your battery to the auto parts store or battery dealer and have them load test it using the small battery setting on the load tester. A modern load tester will be the newer digital type load tester with a clear readout of the percentage of the true condition of the battery. No matter what the salesman tells you, if the battery will not read a minimum of 90%, replace it. Spend the extra $30.00 for a really good battery, perferably a sealed maintence free battery, not a wet cell battery.
    The reason your charging system is not putting out over 12.4 to 12.6 is your existing battery will not accept more than that.

    A Yasusa battery ( the oem battery in Bombardier products ) battery condition chart tells us that a fully charged 12Vdc battery, when 100% charged, will hold 13.1 Vdc after one hour after removing from the charger. Few actually live up to that promise, but most will hold at least 12.9 one hour after being fully charged.
    At 12.8 Vdc, your battery has lost about 20% of it's cranking power.
    At 12.5 Vdc, it is now at about 50 % charged.
    At 12.2 Vdc, you are down below 40% charged.
    At 11.9 Vdc, you are less than 25% charged.

    To even be TRYING to run a fuel injected motor with a 25% charged battery is asking for chicken salad to be made from chicken shiat. Your 11.9 Vdc battery is well under 25% charged.
    A good working charging system , when confronted with the task of recharging a battery with 11.9 Vdc in it, would normally put out around 13.4 to 14.5 Vdc from the regulator, and almost never under 12.9 Vdc minimum at midrange rpm and above with a good ( but drained ) 11.9 Vdc battery that can accept the charging rate coming back into it, unless the battery it is trying to charge is a less than good battery and will not accept the full amount of charge available to it because the battery itself is junk.

    After installing a fully charged up new battery, retest the charging system again. If everything in the charging system is in good condition including the stator, magneto, rectifier/regulator assembly and wiring and grounds, Your voltage meter should read around 12.8 to 13.2 Vdc when you rev the motor up to midrange rpm and above.

    That 12.4 going into your battery from the charging system will not be 12.4 Vdc by the time it has lost some of it's power as it leaves the battery from the sulfated cells in the battery, plus losses from wiring and grounding resistence, the electrical system parts and pieces ( ignition, starter, fuel pumps, ect ) are not even recieving around one half or less of the power that you are recieving from your charging system.
    I am going to go out on a limb here and say that all of your problems are stemming from not having a decent battery in the boat.
    Every symptom that you have described can be explained by the electrical system ( especially the ignition module ) is not recieving the power that it requires to run a fuel injected motor.

    To be sure it will, install a new quality battery, clean the terminals connected to the battery, and especially the grounding cable terminal bolted to the engine cases at the cases, plus the case surface that it connects to. At the front magneto cover, you will find two or three small guage black wires bolted to the mag housing cover bolt on the side of the mag cover. These are very important grounding wires and they cannot be corroded or mounted over paint, corrosion or scale, nor can they be loosely mounted. These small black wires ground out every part of the ignition system, including the module, fuel pump, ECU and EMS, guages, DESS system and almost everything electrical that runs your pwc. Dirty connections double and even triple the amount of loss in an electrical system.

    Did you know in order to PROTECT the ignition module from heat damage, your ignition system will completely shut down automatically when the voltage going into it drops below 10.1 Vdc ?

    Other things we mechanics notice are how hot a starter motor and starter relay and battery cables get when subjected to low voltage when attempting to be used with a less that well charged battery. When voltage drops, electrical parts get very hot, especially solid state circuit boards, like those used in the computer type modules that runs your RFI engine systems.

    This is why your owners manual states that regular maintence of the battery is mandatory, not optional. I just wish folks would actually do more than just read an owners manual then store it away to never be opened again.

    Just think how long those parts would live if not overtaxed by such a simple thing as poor maintence of a battery. 11.9 Vdc, you should be ashamed of yourself ! On the otherhand, 90% of pwc owners are in the same boat as you

    It keeps shops like mine in business.

    Bill O'Neal
    WCM
    Last edited by Mr. Bill; 07-03-2010 at 11:52 AM.

  10. #10
    PWCToday Newbie srcpaint's Avatar
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    Re: 787 RFI Problems

    Bill, I think I found the problem, come to find out my wear ring was completely gone other than the edge and a peice about the size of a quarter stuck to the edge, I am going to buy a new battery too, I already put the new ring in, and it sounds much better already(out of the water), I don't think I will have a chance to get it in the water till Tuesday, but I will let you know

    Thanks for your help, hopefully I will not have to bother you with more questions
    Shawn

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