xp 650 won't go over 4000rpm. Typical :(

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skodatomek

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Hi guys!
Not been here for a while , but got problem again.
Stripped carb, cleand tank, replaced fuel feed pipes, put inline fuel filter and all was fine till i put jetski on water. Couldn't pass 4000 revs, and backfires. Fiew times reached like 5500 but after right turn gone back to 4000 and thats it. Can run like that all day.
Also found crap in fuel filter (one in front of fuel selector).

What alse i can do?
Clean carbs again, add another fuel filter but why i happend on water?
Please advise
Thanks
 
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I would re-check your carb cleaning. You might have something wrong inside. The carbs should be set to" 1 1/2 " on the low speed and "0", on the high speed screws.

Karl
 
I´ve got the same problem on my sportster 4 tec, I don´t know if it goes into limp mode because somethings wrong. I have called around a couple of shops and two of them told me it could be a ignition coil gone bad.
 
Thanks. I've spent fiew hours on cleaning. Stripped to bits and removed all jets put all rubber gaskets and membranes on side. Then flushed with carb cleaner and blowned up with air gun, But as I'm said i've found some "sand"?. Tank was removed and when i put him back into hull, was clean like new.
Will do that again and i try to remember setings for hi and low revs (completly missed that thing last time).
Will let you know about the result
 
You shuold start a new thread...

kaparn said:
I´ve got the same problem on my sportster 4 tec, I don´t know if it goes into limp mode because somethings wrong. I have called around a couple of shops and two of them told me it could be a ignition coil gone bad.
Click to expand...

Your problem isn't the same thing as you have a 4 tec engine, with no carbs.
You might want to start a new thread so you get better information.

Karl
 
To kaparn.

I've been that way before. Irregular run, won't pass 4000rpm, and bacfired.
In the workshop they told that they cand find the fault and charged me 60 pound, also said if I pay another 1000 they will solve the problem lol
Took it back to home, cleand carbs and was running like new!!! till i put him on the water. Then problem started again :(
 
I'm putting all my money on a bad ignition system. I think this is probably both of your problems. I believe with your 4-tec you have 2 of everything. So you have 2 coils. One of your coils might be bad.
You both need to check the dwell or duty cycle; the low voltage problem can be traced. :cheers::hurray:
:agree:
 
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On a 4-tec engine there is a coil for each spark plug...2 strokes are a complete different engine than the 4-tec. The same advise is different from each engine.

Karl
 
Ya, when backfiring it's usually due to a bad air/fuel ratio. Adjust your carbs appropriately like karl said for your model and year and make sure your fuel system is clean, that should fix your problem. Also when cleaning the carb's did you make sure you removed and cleaned the main jet and pilot jets? Also make sure the needle valve is seating properly and the see saw device its attached to is properly set. Sometimes you have to slightly bend these to set them properly. I suggest you download a service manual on how to rebuild your carbs. Will help you tremendously

Does your jetski leak any water near the driveshaft?
 
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No, there is no water leak, it's bone dry. But I've got leak on exhaust system and some of the exhaust gases going into hull. Does it make any difference?
Thanks.
 
Yup, that's gotta be your problem. Fix the exhaust leak and it should run like new:cheers: The exhaust leak is suffocating the engine of oxygen causing it to backfire.

My XP had a leak at the driveshaft and when the driveshaft would turn it would spray water everywhere and I was wondering why my jetski would bog down. With the seat off it ran like it should, when I put the seat back on it would bog down. Figured out that moisture from the driveshaft spray was getting into my air filters causing it to bog. Fixed the leak and ZOOM back to racing.
 
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Good thinking, but that problem apears, even when the seat has been taken off.
Yesterday I took the carbs off and I'm gonna send them to the propper garage. If that don't solve the problem, then i will start looking into electrics :(
Is the coil fault possible with the symptoms like I've got?
Thanks
 
Put a meter on your battery, write down the voltage at first, then start up your ski. Rev it to 5500rpms and see if the voltage goes over 15VDC. if so your rectifier is junk. To further see if that is the problem go to your grey electrical box and find the rectifier, unplug the red wire and see if it runs better.

A rectifier takes ac voltage from the stator and converts it to dc to charge the battery. If it is faulty it will send ac voltage into your ignition causing problems and running like crap in the rpm range your talking about.
 
I think it is 94 model, its red and green anyway.
Just stripped carbs and put them back together, but it dont make any difference.
Still ok up to 4000 revs with maximum of 6200 and then backfire from time to time. Battry is brand new.
Will check that rectifire.
Sorry what is it that RV?
Thanks
 
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i have the same problem in a 96 GTX..

i have researched heaps, and people claim its the stator (thing that feeds the rectifier).. if it shorts circuits, it blows up the rectifier, and then feeds irregular power back into the electrical system which causes the engine to backfire and run very poorly above 4000 thousand rpm..


my problem started after a few months storage, in which i cleaned the carbs, etc.. when it came to the start of the season to use the ski again, i instantly thought it was the carbs and what i might have stuffed up.. however, while using the ski, it suddenly started working perfectly and was super responsive.... this lasted until i next turned off the ski!

since then, i took the ski out one more time, and it stayed under 4000rpm running poorly!.. i have since come to the judgement it must be electrical, and i am hesitant to fix it!
 
fire said:
i have the same problem in a 96 GTX..

i have researched heaps, and people claim its the stator (thing that feeds the rectifier).. if it shorts circuits, it blows up the rectifier, and then feeds irregular power back into the electrical system which causes the engine to backfire and run very poorly above 4000 thousand rpm..


my problem started after a few months storage, in which i cleaned the carbs, etc.. when it came to the start of the season to use the ski again, i instantly thought it was the carbs and what i might have stuffed up.. however, while using the ski, it suddenly started working perfectly and was super responsive.... this lasted until i next turned off the ski!

since then, i took the ski out one more time, and it stayed under 4000rpm running poorly!.. i have since come to the judgement it must be electrical, and i am hesitant to fix it!
Click to expand...


My vote goes to electrical to. Theres not that many electrical parts. With some troubleshooting I am sure you can track it down.
 
Hi guys just a quick reply to thread only had a few mins to read it all so sorry if i quote the same as some of u guys.
I think you need to confirm that you have a MECHANICAL FAULT or ELECTRICAL as either of these can give same symptoms i know from experience so I think you have a Stator High Speed fault on the windings can you check with Ohm meter info of results are in the shop manual.

Sorry for jumpin in guys ...... Every Little Helps
 
Hi!
I'm just about to buy, a complette electric box (next to fuel tank).
On the pictures it looks slightly different to mine (probably newer bigger
engine).
Are they all the same? As long as they are two stroke two cylinder engines?
Is thre any other electric part inside the engine which can go wrong?
Please let me know?
Thanks
 
yes they are different. not necessarily interchange able

many can be interchanged but 580/650/650x/720 use different brains mpems
 
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Hey Skoto,
When you pulled the carbs, how did you do it?
Did you pull the carbs off the intake, or did you pull the intake and carbs together? If you pulled the carbs and intake together (easier) then did you make sure your RV (rotary valve) plate stayed on the splined shaft? If that came off then you will need to reset the timing. Like Timmyboy was saying.
 
Hi
I did pull the carbs off the intake..., setups are like Kustomkarl said...


...Can RV get out of timing by him self? With no reason?
 
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If you pulled the carbs off the intake and did not pull the intake off, then I am wondering if the flywheel key is sheared. causing the "out of timing" condition? Can't hurt to check it out!
 
Just solved same problem on my 94 XP took flywheel cover off and one of the wires in there had unplugged itself, no more backfires!
 
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