'92 SN dies at WOT

**Quinner** · 12-06-2006, 01:23 PM

RE:

I had similar problems on two boats:

77' SN acted like it was starving for fuel at WOT, great at other speeds, it turned out to be the anti-siphon valve which is located just after the elbow coming out of the fuel tank, it was filled with debris, cleaned it out and all was good. Do not know if it is the same on a 92.

93 SN had the Pro-tech, symptoms were a little different and did not always occur, mostly coughing, backfire or running rough at higher RPM's or WOT, sometimes would not start after being shut off at normal operating temp, had to cool for a few minutes with dog house open to start again. Picked up a conversion kit which eliminated the pro-tech from DIM, solved the problem. I do not think replacement parts are available for the pro-tech and according to DIM they started seeing alot of pro-tech failures at or about 10yrs old.

Good luck.

**surroundsound64** · 12-06-2006, 02:15 PM

RE:

It's definately losing fuel. Check that anti-siphon valve as well as other related things. Gas tank vent, fuel filter, accelerator pump (although I highly doubt that's the problem or else it'd die right when you put the coals to it), ect...

Good luck.

**TRBenj** · 12-06-2006, 02:54 PM

Re: '92 SN dies at WOT

Originally posted by backfoot100

the boat will just die. Like someone just turned off the key.

This does not sound like a fuel issue.

By all means, check all the simple things in the fuel system- you have nothing to lose. If it simply cuts out and doesnt sound like its running out of gas, I would suspect the ignition.

Like Quinner said, PCM does not support the ProBoss Protec systems anymore- apparently they are saving the replacement parts for TBI motors that rely on the system more heavily. If you decide to replace the Protec, you have the option to buy the kit from PCM or SkiDIM, but there are also other options. Expect to pay $400+ for a brand new setup.

**darrel409** · 12-06-2006, 09:22 PM

RE: Re:

If it dies quickly^^^^ make sure to check all your grounds and elec connections for shorts loose or weak connections.

**Fast351** · 12-07-2006, 08:38 AM

RE: Re:

When it dies, does it die quickly and stall, or does it slowly nose over and lose power until it stalls?

If it dies quickly, that points to ignition. If it slowly noses over that indicates a fuel starvation problem.

To me it sounds more like a fuel starvation problem. That's why it runs 30-90 seconds (fuel in the float bowls).

If this is the case, check for blockages. The anti-siphon valve has been mentioned. This is where the blockage is likely occurring. What happens is the crap from the bottom of the tank is getting sucked into the dip tube, and blocking the anti-siphon valve. When the suction from the fuel pump goes away, the crap drops back into the bottom of the tank, and the boat will usually start again.

Two ways to fix this.

1) Temporarily replace the anti-siphon valve with a brass straight through fitting. Run the boat for a while this way, and the crap will go into the fuel filter. Replace anti-siphon valve and fuel filter. This is the safe way.

2) Empty fuel tank using hand pump. Use the access hole for the fuel gauge/pickup tube. YOU MUST GET ALL THE FUEL OUT! Use compressed air to evacuate the fuel tank of vapors. Then FILL THE TANK WITH WATER. Use a wet/dry vac to pump the water out and vacuum the stuff out of the bottom of the tank. Leave the tank open and let the rest of the water evaporate. THIS IS A VERY DANGEROUS OPERATION, ONLY DO THIS IF YOU FILL THE TANK WITH WATER!

Gasoline vapors will explode in a wet vac. This is why you must completely displace the fuel vapors with water.

I have done this because I had a boat which had an algae in it that looked like small wax BBs slightly brown in color. They sink in gas, to get sucked into the dip tube. They were too big to go through a brass fitting and I had to clean the tank.

**backfoot100** · 12-07-2006, 02:42 PM

Thanks for the replies guys. I'll try to ad to this.

I have a hard time believeing that the fuel is the problem. If the fuel is being shut off to the engine, the float bowls would empty and the boat would start to cough and sputter before it dies. Then the engine would have to crank awhile to fill the bowls again before it would start. It's not doing anything like that.

It just dies immediately and there is no indication that anything is wrong. It's like you turn the key off. Then after you take your heart out of your throat, you just touch the key and it starts right up. It doesn't even turn over half a turn and it's running. If it was EFI, then yes, the fuel could certainly be an issue.

I can check the anti-siphon valve, but I think it's probably ignition related. I talked with Richard and DIM and he thinks the same thing. Good idea from darryl409 to look at the grounds and connections. I'll have to try and get a wiring schematic to look at that.

Thanks again for your help guys. I appreciate it. Other than that, my brother-in-law absolutely loves the boat.

**tommer12** · 03-27-2007, 03:26 PM

I have a 92, but the not pro-boss. I had some carb problems last year and I went over it head to toe. Out of the hole, it would backfire, but if I slowly brought it up, it was fine, and then all of sudden, die out. After all that.. it turns out SkiDim gave me the wrong spark plugs. Which inturn, screwed with my ProTech ignition pack. The computer couldnt calculate the sparks correctly and would just shut off pretty much. (is what I concluded) The computer is trying to time everything based upon rotation, spark, etc. So at the higher RPMs, I think it just said. F(*(*, shut down.

Also, the boat has the goofy 2500rpm auto shut kick down to prevent overheating.

I think if you are shutting off cold, boat comes to a stop, you have to start it again, and it's fine... I would go over the iginition system. Check your plugs, replace them. I don't have the model on me that i used, but once I replaced them, everything was fine. I evn had my carb rebuilt thinking it was some kind of problem with that. Not really...

It's not uncommon also for the ProTech to finally give out. You have to replace it with a DIY type system then and it's $$$$. Ive been lucky so far...

Check grounds at the battery, that little breaker button area, look for cracks in the protech system. If you see any, bad sign, the "inards" are starting to go.

good luck.

**KaNi** · 03-30-2007, 01:28 AM

I dont know if that year has the emergency cut off switch. I had similar problems with mine..mostly at WOT but then started happening whenever it wanted too. One of the wires was loose on the back of the switch. Runs great now. You could prob straight wire it and bypass the switch, go WO and see what happens. Good luck

**DBorrelli** · 04-06-2007, 03:32 PM

Hello Im new here and a new ski nautique owner! I recently purchased a 78 ski nautique and shes in fair condition. The boat has the same problem mentioned above. Once it gets to about 35mph it just cuts off. I unhooked the fuel line from the tank and stuck it securely into a gas can and the problem went away. I know there are procedures to fixing this but would buying a new fuel tank be unreasonable or is there a real simple way to fix this? (Considering I no knowledge of engine systems)

If installing a new fuel tank is a solution are there any procedures that i need to follow?

**Quinner** · 04-06-2007, 03:57 PM

Re: RE:

Originally posted by Quinner

77' SN acted like it was starving for fuel at WOT, great at other speeds, it turned out to be the anti-siphon valve which is located just after the elbow coming out of the fuel tank, it was filled with debris, cleaned it out and all was good.

Check the anti-siphon valve which should be located as described above.

**DBorrelli** · 04-15-2007, 08:55 PM

Well I replaced my gas tank and the problem went away. If anyone else has the same problem (boat dying at higher speeds) then the problem is within your gas tank. Thanks for your help

DB

'92 SN dies at WOT

'92 SN dies at WOT

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