99 rfi gsx rough run

[zacc300]

Hi all i have posted before regarding my gsx rfi running rough between 1600 to 3000 rpm .
Here is the update as to what has been done , fuel pressure ok, the computor showed no faults so that ok . The tps was reset aswell , the plug leads where cliped back. After all this it still has the problem tommorow i am going to check the spray pattern on the injectors to make sure there ok.

Is there any thing to do with the stator that could be doing this?
Thanks in advance for your help.

 

[Dr Honda]

If it smooths out after 3000 RPM... then no... it probably isn't the stator. Electrical issues normally get worse with higher RPM. But... for giggles... put a volt meter on the battery and bring it up to 5000 RPM. You should be seeing 13.5 to 14.5 volts.

Have you checked the basics? Are the RAVE valves working? Are the RAVEs both adjusted the same? What's the compression? Is there any signs of crank seal leaks?

Also... how rough is it? Is it so bad that you don't want to ride it? a 2-stroke engine... even if it's injected... will run rough when not at it's designed RPM range. It may feel like it's only running on one cyl until it clears out.

Since you don't have a Di engine... I don't think the spray pattern will make much a difference, as the fuel is still being introduced into the lower half.

 

[Minnetonka4me]

Those RFI models run like crap when water is in the gas tank...I beat my head in trying to figure out why it ran like crap and that is all it was.

 

[Dr Honda]

Those RFI models run like crap when water is in the gas tank...I beat my head in trying to figure out why it ran like crap and that is all it was.

Yep... you can check that too. Or the easy way is to pour half a bottle of Marine Stay-Bil in the fuel. That will help purge it out.


One other thing I thought about... If it's a harsh vibration that you can feel in the seat and handlebars... you may want to check the driveshaft. It could be bent.

 

[zacc300]

Thanks guys , yes she chugs it all most like it will fire every now and then on one cylinder. fuel pressure is good 53psi compression 152 on both . Yeh this has stumped me . when it is on the trailer and the bum in the water it will rec to 6800rpm but every now and then it will have a cough. yes both raves are adjusted the same.
Any more advice would be appreciated.

 

[Wire4Money]

I believe these idle on 1 cylinder (to save fuel)

 

[zacc300]

I have heard this but it idles great.
Took it out today for a squirt , it definatly not running right down low (unless this is a characteristic of rfi ) from idle to about 2800 to 3000 rpm it feels like it will run on both cylinders then decide it wants to run on 1 .
It almost feels like a plug fowling but they check good.
I have tried .5mm as per sticker on ski and .8mm still no difference.
Flat out it reaches 6800rpm.

Still looking for suggestions .
Thanks

 

[zacc300]

Also put in a fuel additive that absorbs water , still no joy.

 

[Bills86e]

Need clean fuel

53 is on the low. It should be 59 psi on that model. I think you should pull the fuel
pump out of the tank and clean or replace the filter. I have brought many pumps back to life by takeing off the craddle break it down to the pump alone. I mix a
mixture of 1/4 Tolulol (toluene) and 3/4 gas into a container to imerse the pump 1/4
way, put a return tube into the container and hook 12v and let the pump cycle about 4-5 minutes, that gets all the orange crap out of the internals. That mix will
also clean the screen too. I advise swabbing the tank with a rag on a stick after
the gas is removed by a simple syphon hose in there. repete every two years.

Use diligence by doing this outside in a ventilated open area, and caution
not to get in your eyes or skin. Ask your hardware store for the proper gloves
when you purchase the Toluol. Its about $17 a gallon.

Gas can go bad in 3-4 weeks without the use of Stabil, and chemically change. Adding an Oz or two of Injection oil to a tank of gas will film the tank walls and will help moisture from permiating thru the walls.

I edit/add a link to your fuel system: http://partsfinder.onlinemicrofiche...oem/Seadoo_PWC.asp?Type=18&A=70&B=14&Action=O

 

[Dr Honda]

I believe these idle on 1 cylinder (to save fuel)

Nope.

They only run on one cyl in "Limp" mode. The fuel is what properly transports the oil into the engine... so if it cut fuel... it would cut oil. Yes... it would still dribble down the manifold... but it would just pool in the engine.

Well... anything electrical would get worse with higher RPM's. But... since you've checked everything... I would start all over again. You are missing something.

Please see this thread for why.


http://www.seadooforum.com/showthread.php?t=33643


Also... start to check for things that aren't obvious. Pull the spark wires out of the coils, and check for burns. Make sure the spark wires aren't leaking. Make sure the wires going to the injectors are clean, and the connections are tight. Pull all wires at the electrical plugs. They can be broken at the pins.

This one isn't going to be easy to find.

 

[Sea Dood]

Sorry to correct you, but all the RFI's run on one cylinder at idle once they warm up. (they run on two when cold) This was done for emissions reasons. The 98-03 models ran only on the front cylinder at idle, whereas the 04-05 models alternate which cylinder it runs on during idle.

Also it is not proper to say the fuel carries the oil. The oil injection dribbles it into the intake like any other Rotax rotary shaft engine, and the flowing air allows the droplets to hit the crank, and then it is turned into a mist from the rotating crank. The flowing air charge then moves up the transfer port. The injectors are located in the transfer ports, and the air/oil mist charge mixes with the fuel at this point and is carried up to the combustion chamber.

 

[Dr Honda]

I'm always open to correction. I'm not a "Pro" mechanic, and I was under the impression that they only ran on one jug in Limp mode.


As far as fuel transporting the oil... it does. Yes, the oil "Dribbles" into the manifold. It's not under pressure, and since the oil's partial pressure is very low (as in high vac) it won't "Atomize". When the fuel sprays in... it mixes with the oil... and the light-ends of the fuel, do the transporting.

let's just agree to dissagree. :cheers:

But regardless how it happens... If the RFI does run on one jug at idle... that may be what he is feeling. I've only played with a few RFI's and Di... and I never felt anything that would make me think something was wrong at low RPM's.

 

[Sea Dood]

Well, you are correct that they run on one jug in limp mode. That's because the RFI limp mode is idle.

I can agree to disagree on the oil thing. I appreciate different points of view, learn something new every day, and like to keep things friendly.

 

[Dr Honda]

Well, you are correct that they run on one jug in limp mode. That's because the RFI limp mode is idle.

So... what RPM does the second jug come back on line?

 

[Sea Dood]

So... what RPM does the second jug come back on line?

I am not sure, but believe that it is not RPM dependent. ( it is not documented anywhere, and I haven't tested for it) I believe it is TPS percentage-based. The control system on the idle on a RFI is kind of wacky, as the air fuel relationship is dependent on an accurate setting of the TPS, followed by setting the idle screw just right. You back off the idle screw to close the throttle plate, reset the TPS, then turn in the screw a number of turns. At this point, the ECU "sees" roughly about 6 degrees of opening. I know a lot of guys that have given us feedback about how touchy this is. (Sea Doo corrected this with the 4-TEC systems with an idle bypass valve that allows the ECU to set the proper idle speed.)

I believe the ECU must use some logic that says "if the throttle position sensor value increases by X, allow normal ignition firing" Otherwise, if it were RPM dependent you would have a lag coming out of idle.

I plan to create an RFI emulator for testing purposes; I'll try to remember to test out this theory when I get it done and post a follow-up.

 

[zacc300]

Thanks guys i have been thru every thing, wire cunnections etc . i thought if i had 52psi fuel pressure and that was low ( should be 59psi ) it would not reach peak revs . The batterie is new and charging no fault codes at all TPS resett. 2 set of plugs to make sure i did not get a bad batch. This one is going to drive me nuts. I only got the ski 3 weeks ago and could not water test it at the time . It has done 113 hours , not many at all for its age.
Will look at the pump today , see if i can get the pressure up.What should the plug gap be on the plate on the ski iy says .5 but i have been told .8 ?

Just an update , i pulled the pump out today bottom filter looked clean the internal one has a fair bit of crapp on it.
Can i take the bottom of the canaster off were there are 2 pop rivets holding it in with out doing any damage. Also when the bottom is replace does it have to be a perfact seal.
I tried pulling the pump out of the internal filter but it does not want to come out.
Also on the coil do the ingnition leads scew in like on the plug caps?
Checked the resistence on the plug caps one is 3.4ohm the other 5ohm
Thanks guy i realy would be lost with out your help.