1991 super jet 650 will not accelerate

D

DamonT

Location
Nine Mile Falls Wa
Stator went out, relaced stator And it started no problem, however will not accelerate. Replaced carburetor and slaved in all electrical components from another SJ 650 which runs great. Still same problem. Circled back to stator, believing the initial stator I installed must have been defective. Replaced stator again……..same problem, will not accelerate. Seems like a timing problem but can’t figure it out. Lined up timing mark on stator to middle. Woodruff key is installed and intact. I’m at my wits end.
 
D

DamonT

Location
Nine Mile Falls Wa
mthomps said:
Sounds like a broken throttle cable? What happens when you try to give it throttle?
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The engine just gargles. Spark plugs are wet. My most recent attempt to fix this problem is I changed out the reed valves. No go. However, after changing the reed valves I did notice the jug gasket has a leak while running it for a leak check on the reed gaskets. I don’t believe a leaking jug gasket would cause this problem however it’s a problem that needs to be fixed. However, I have never had a jug gasket leak before so I don’t know what the symptoms would be.
 
mthomps

mthomps

Location
Cleveland
An air leak on the base gasket will have random nightmare inducing symptoms. You need to deal with it before you do anything at all.

You should also replace crank seals, and all other gaskets. You are taking the motor apart between a base gasket and crank seals anyways. Inspect and do proper leak down tests until it's right.

Also, I feel for you. First ski I ever bought had a leak on the base gasket. That sh** f***ed with my head dude. But now I know if it doesn't make sense use the leakdown test kit I put together.

Pump to 10 psi, if it doesn't drop below 8 in ten minutes it's good. It doesn't need to hold it until your kids graduate college, but that gauge needle shouldn't move at a glance.

Start there, and if that doesn't work someone who knows more than me will likely chime in.
 
D

DamonT

Location
Nine Mile Falls Wa
mthomps said:
An air leak on the base gasket will have random nightmare inducing symptoms. You need to deal with it before you do anything at all.

You should also replace crank seals, and all other gaskets. You are taking the motor apart between a base gasket and crank seals anyways. Inspect and do proper leak down tests until it's right.

Also, I feel for you. First ski I ever bought had a leak on the base gasket. That sh** f***ed with my head dude. But now I know if it doesn't make sense use the leakdown test kit I put together.

Pump to 10 psi, if it doesn't drop below 8 in ten minutes it's good. It doesn't need to hold it until your kids graduate college, but that gauge needle shouldn't move at a glance.

Start there, and if that doesn't work someone who knows more than me will likely chime in.
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Thanks for the info brother. I’m not familiar with the leak down test. Do you know where I can find instructions on that procedure?
 
mthomps

mthomps

Location
Cleveland
I'll send pics of my kit tonight after work, but it won't be till about 1 am eastern.

Google "leakdown test site:x-h2o.com" to understand how it works.
 
mthomps

mthomps

Location
Cleveland
Good God tech has passed me by. I meant to upload the pick of my block off kit but now it won't let me fix it. I'll try again tomorrow. Sorry, lol
 
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mthomps

mthomps

Location
Cleveland
It's saying the file is too large. I'll text you the pic if you want. It's just 2 block of plates and 2 rubber gaskets to seal it. Then you need a pump and a gauge to pump it up and get a reading. Those I cant take pics of because they are being borrowed at the moment
 
D

DamonT

Location
Nine Mile Falls Wa
Thank you so much MThomps, that is an excellent article! However, although it’s an item that has to be addressed, I don’t believe it is my issue. To recap, the original problem was the stator went out, I replaced the stator, afterwards the engine would not accelerate. I then used an aftermarket CDI from another JetSki and it worked, for about 10 minutes and then burned out that aftermarket CDI. I put in an OEM CDI, and the engine will again not accelerate. I tried advancing the timing, no go. I replaced all of the electronics from a working JetSki. Still no go. Ordered a new stator. Put in a new stator thinking the original one was defective, still no go. I’m next going to try to remove the stator and fly wheel from the good operating JetSki which is also a 650 and try that. If that works, then SBT is selling defective stators. I don’t believe that is the case but I am slowly eliminating all other possibilities.
 
mthomps

mthomps

Location
Cleveland
Hey now, best of luck to you. Might wanna swap voltage regulators if you are messing up known good cdi's.

All I know is you described a leak on the base gasket which screams to me pressure test that motor.

6m6 motors are reliable as hell with low end grunt (with proper pump tuning) but nothing survives an air leak long term
 
D

DamonT

Location
Nine Mile Falls Wa
JC-SuperJet said:
Let me save you some Money and Time:

STOP BUYING CHEAP MADE IN CHINA STATORS!

It is almost Universally known that the Chinese are very stingy with the Copper in the Coil Windings, they either don't use enough Copper Wire or the "Copper" is some cheap Alloy, either way, they are poor qualitiy. Thus, Beware of Electric Motors, Welding Machines and anything Electrical Made in China that relies on Copper Wires to perform.

Only buy OEM Stators, New or Used.

Buy a good used OEM Stator from Jet Maniac, or if you have a faulty tired OEM Used Stator, it can be remanufactured by Jetski Solutions, to better than New quality.

Hint: OEM

Same goes for Aftermarket CDIs. Only MSD and Zeeltronic CDIs are reliable.

And, like Mthomps said, replace the Voltage Regulator/Rectifier with a good OEM one.

Then check and ensure that ALL GROUNDS are clean, tight and have near Zero Ohm Resistance. Bad Grounds will also burn up CDIs.

Bad (broken) Internal Ignition Coil Wires can also hurt a CDI and will cause misfires. Ignition Coil Wires ARE also Ground Wires in a real sense since they carry 30 KV to its final Ground, which are the Spark Plugs in this case. If the Ignition Coil cannot discharge its Current load quickly and efficiently, the Current back-up will burn up the CDI.

Working backwards, the Spark Plugs get their Energy from the Ignition Coil, which gets its Energy from the CDI, which receives its Energy from the Stator Coil. Regulating and safely limiting the amount of Current from the Stator Coil to the CDI, is the Voltage REGULATOR.

The Voltage Regulator/Rectifier also converts (rectifies = straightens) the AC Current from the Stator Coil to usable DC Current for the CDI.

If the Voltage Regulator cannot limit the Current going to the CDI, the CDI will burn up!

The Battery also has an Internal Ground. If it's bad, same problem. Can burn up a Voltage Regulator and/or CDI. That's why I don't buy cheap Batteries. Cheap Batteries are easily damaged by Vibration, Impact and Heat and die too soon anyway. The Battery is a Critical Part of the Electrical System.
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Thank you for the information my friend, it’s greatly appreciated. When I figure this out I will post the fix.
 
D

DamonT

Location
Nine Mile Falls Wa
Renato_ataide said:
Did you pay attention if your stator is correct?, I ask why the 650's stator is similar to the 700's, but incompatible...
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Thanks for the information, always good to hear bits of knowledge and experience. As far as it being the correct stator I have to assume it is. I ordered it twice from SBT and it says for SJ650, but neither worked. I’ll be getting an OEM stator but damn they’re expensive.
 
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