1998 GSX Limited Slow crank

[SIMPLEARKANSAN]

1998 Seadoo GSX Limited with slow irregular crank. New fully charged battery. After about 4 cranks it will start but runs rough and backfires occasionally. I can take the ground wire and connect to battery and connect a jumper from positive side of battery to starter side of solenoid and the engine turns over at a rapid pace like normal. Plugs in or out doesn’t matter when attempting to start normally. I’ve ruled out the starter, made sure my reed valves were good, swapped starter solenoid. Checked all grounds and cleaned all connections. I’m thinking it’s something to do with the ignition system or woodruff key. When I put a voltmeter on the battery side of the solenoid I get 12 volts. When I put the voltmeter on starter of the solenoid and push start I get 12 volts initially and then the numbers bounce all over the place. The jet pump isn't installed. Could it be the start/stop switch, but that wouldn't explain the engine backfire.

 

[burtshaver2021]

This is just a stab in the dark but what about the voltage regulator? With the volts jumping all over the place

 

[tobytd]

Google / you tube : Voltage Drop Test

 

[SIMPLEARKANSAN]

Thanks, I will look into that tobytd. Burtshaver, I'll check the rectifier also.

 

[SIMPLEARKANSAN]

I checked pin #24 on the #connection and I had continuity. I also checked the 2 wires that connect to left front of engine. I started the engine for you to hear the backfire and I thought I’d check the rectifier. It doesn’t appear to be charging. Outside of the woodruff key, I can’t think of anything else?

 

[burtshaver2021]

Still putting my bets on voltage regulator, I’ve heard they can make a machine just run like crap all the way around. I would also have a look at the rotary valve, make sure it’s in time, not damaged, no play in the rotary shaft. These are just guesses from my limited experience, good luck though

 

[Grim]

I had this problem on my 98 GTX ltd, it was the wires in the rear electrical box, Mine had three wires on one of the bolts to the coil, and one or more of the wires were not making a good contact. Check your power and ground wires, verify they make good contact.

 

[SIMPLEARKANSAN]

I had this problem on my 98 GTX ltd, it was the wires in the rear electrical box, Mine had three wires on one of the bolts to the coil, and one or more of the wires were not making a good contact. Check your power and ground wires, verify they make good contact.

I checked continuity on every wire in the rear electrical box. I even swapped out the female plug in the rear box with all its connections. Everything checked out good. I was hoping that would be the issue. I’m afraid it’s the woodruff key and it’s out of time.

 

[SIMPLEARKANSAN]

Still putting my bets on voltage regulator, I’ve heard they can make a machine just run like crap all the way around. I would also have a look at the rotary valve, make sure it’s in time, not damaged, no play in the rotary shaft. These are just guesses from my limited experience, good luck though

It’s a 951 and has reed valves. It does kinda behave like a 1996 GTI I had that the rotary valve was the issue. With this model I would have to purchase an external rectifier. I added one to my 98 thx limited, so at end of summer I may add it and see if it makes a difference.

 

[etemplet]

It’s a 951 and has reed valves. It does kinda behave like a 1996 GTI I had that the rotary valve was the issue. With this model I would have to purchase an external rectifier. I added one to my 98 thx limited, so at end of summer I may add it and see if it makes a difference.

Never thought of that. Great idea !!

 

[SIMPLEARKANSAN]

This may be a long shot, but the original issue with the ski was the woodruff key had broke and the flywheel key slot was destroyed. I bought a whole new bottom end, flywheel, and cup. The magneto cover has the pickup coil that has a magnet. I don’t remember cleaning the pick up coil. So if they’re are metal fragments on the pick up coil could this be causing my symptoms?

 

[2strokeboy]

That could definitely interfere with the pickup

 

[SIMPLEARKANSAN]

I think I have figured out my problem. The engine I bought had a flywheel cup and flywheel from a dual coil system. I now have the correct flywheel and cup for a single coil 951. Will update my results after I install the corrrect parts.

 

[etemplet]

I have had issues identifying those flywheels and have had to resort to creative identification solutions. ie. checking ebay and looking for pictures of the item I need then blowing up the picture and reading the numbers off the flywheel and comparing them to mine.

 

[SIMPLEARKANSAN]

I have had issues identifying those flywheels and have had to resort to creative identification solutions. ie. checking ebay and looking for pictures of the item I need then blowing up the picture and reading the numbers off the flywheel and comparing them to mine.

Most of the Ebay ads the pics are so blurry it's hard to see the small numbers. They don't list them in their descriptions either. They will say fits a 951 GSX, but the later models have the dual coil setup so it's misleading unless you can pinpoint what model the part came from. Hopefully, I have figured out my issue.

 

[SIMPLEARKANSAN]

Slow crank fixed. Model specific flywheel and cup installed. Noticed my accelerator pump isn’t working so I’ll pull that why I have the exhaust off. Carb and accelerator pump was rebuilt with Back to OEM kit. May replace the portion of pump that has the brass T.

 

[2strokeboy]

you are most likely missing the check valve in the accel pump hose

 

[SIMPLEARKANSAN]

It’s there and oriented in the correct position. I’ll know more after I pull the pump.