Thread: 96 slt780 stalls
09-02-2008, 12:57 PM #1
- Join Date
- Aug 2008
96 slt780 stalls
I got this 96 slt780 from a guy that had been sitting for 2 years. Well I got it home put a new battery in it checked compression, 130 - 135 psi put some fuel and oil in it and it fired right up. So I took it to the lake and road it a little around the dock and all seemed well so I went across the lake to where we hang out and noticed that it was riding lower in the water , took the seat off and water was up to the top of the battery and bilge pump wasn't running. We pulled it up on the beach and tipped it over on the left side to get most the water out then hot wired the bilge and got it working however now whenever I get going and jump a wave it stalls out when it lands also notice that on hard cornering it does the same, just shuts off, it will fire right back up and runs great on smooth water. I am thinking that I possibly had some water seap into electrical box and splashes aroundto short something? Any other suggestions?
09-02-2008, 01:39 PM #2
- Join Date
- Jul 2007
- near Toronto, Canada
Welcome to the Hulk!
You can find the Polaris 1992-1998 service manual here.
If you have a water leak, you need to find and fix it. Do NOT depend on the bilge pump to keep you afloat!
Per the service manual, be sure you grease the through-hull fitting, and the drive shaft coupler.
You should disconnect the battery negative, and open up the electrical box. It should be completely dry inside, zero moisture. Check front and back sides of the terminal board for rust or corrosion on the connections.
Check for voltage on the Orange wire with a multi-meter. When the engine is running, the Orange wire should have about 14 volts (connect black meter probe to engine ground). When the engine is off, it should have near zero volts. The bilge pump is normally connected to the Orange wire, and runs when the engine runs.
If the Orange wire has no power when the engine is running, then the LR-23 voltage regulator module probably needs to be replaced.
You really want your PWC to be 100% reliable. Being stranded out on the water is no fun, and potentially dangerous. More so if the machine is sinking!
Put it in the water on the trailer (far enough that the jet pump intake is in the water) with the seat off, and see if you can locate the leak. Sometimes the engine needs to be running (on the trailer, in the water) for the leak to appear. Use a small mirror to look under the drive shaft area.
Common leak areas are the seals around the drive shaft of the through-hull bearing, and the speedometer pick-up tube, which connects to a small nipple below the drive shaft.
There are a number of maintenance things that you should attend to RIGHT AWAY, in order to avoid expensive engine damage. Do not run it until you have attended to these issues, as even a short running time can kill the motor if the fuel system is not 100%.
Your engine may be just fine, but MANY new members on here arrive with a similar story... Bought it used, it ran OK or great for a short while, then suddenly it ran very poorly, or not at all. Severe engine damage had occurred, which could have been avoided.
What happens is that the carburetors are not delivering 100% of the fuel needed to keep this high powered 2-stroke engines happy. The engine still runs, and often develops near full power, but the minimal fuel flow means it is actually running very hot on the inside. Soon enough, one or more of the pistons has a hole burned right through the top! This is known as a lean condition burn down.
Do some searching and reading on here, regarding common maintenance issues for Fuji engines on Polaris PWC.
- The primary issue is the fuel system. These older Polaris tend to have problems with;
- Fuel lines need replacing, cracks and failures, including inside the fuel tank.
- Fuel pump can weaken with age, and deliver less fuel pressure than it should.
- Carburetors can become gummed up and clogged with gunk and old gas over time, especially if the machine has been sitting. No additive in the fuel tank can fully correct this.
Best method is to remove the carbs, take them apart and clean thoroughly. The parts need to rebuild a set of carbs is not expensive, and are available from a number of sources.
Also make sure you are using the correct spark plugs. Often someone has installed some other spark plug, and the engine can suffer from it.
09-02-2008, 07:56 PM #3
09-02-2008, 08:43 PM #4
I'd check the electrical box for water and poor connections. I'd also pull the carbs and go through them as well. Be sure to verify pop off pressure.
Oh and WELCOME to the Green Hulk Forums cuda!!
09-04-2008, 01:06 PM #5
- Join Date
- Aug 2008
Thanks for all the suggestions. I will definitely start catching up on all the maintenance items and also think it is probablely smart to clean the carbs. Do I need to purchase an overhaul kit for them? If so who would you recommend? When cleaning them is it best to completely disassemble them and soak them in cleaner or is a simple disassemble and squirting of carb clean through passages followed by compressed air enough? I'm not completely sure that this is the problem but as you guys stated it probablely due anyway. The ski runs great and doesn't actually die until it lands down at which time it is like it is just turned off (no sputtering or rough running) and as soon as the starter is engaged it immediately starts back up. Someone suggested checking the fuel pump but I was looking through the service manual and do not see a procedure or a spec on what the fuel pressure or volume should be. Sorry about all the questions but I am fairly new to the PWC world and have been extremely impressed with the knowledge and advise given on this forum
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