2003 STX-12f

[leejax01]

Thanks for the input guys. In the process of getting a pdf manual as we speak. Also searched STX-12f and read the 7 pages and did come across that topic. Found somewhere local that had the GSS340 &GSS341, but the part number in link was for the GSS342. Found a used fuel assembly at a decent price as the unit was totally shot. The fuel had to have sat for years longer then the guy admitted. Fuel assembly was coated in hardened gunk, so basically needed a new one as well as flushing out the tank. Will chime back once we get the parts in. Thanks again.

[leejax01]

First, would like to thanks Shuswap for the info and meangreenman for the posts as well as OCD Solutions for the fuel pump and amazingly fast shipping. Got the fuel pump in the mail today and dropped it in. Filled with fresh gas and hit the start button. As soon as I said for him to not get his hopes up, it fires off. Get it to run for about 10 seconds then ran the water hose. It initially sputtered a bit, but eventually ran great. Ran out of time, so will water test tomorrow with me on my ski for back up. Got him going to get 4 plugs, but have a question.

Will the ski/ computer run fine with the display not functional?

Thanks again guys for all the info and help.

[meangreenman]

Sometimes a bad dash meter would put the ski into SLO mode only. You will find out when you water test. But there is a way to disable that and put the ski into FAST mode by jumping two pins at the ECU. Test ride first and report back.

[leejax01]

Ok, did the water test and basically how it went. Got on the ski and had to back off the trailer. It acted like it was rev limiting and after some time and throttling, seemed to wake up. Took it out and rode ok to about 30 mph with my gps since the dash no good to see speed. Took it out again and would run to 30 then rev limit after maybe 300 feet. Did that for a few minutes. Stopped and tried to see if running hot by touch or leaking water( another story about a drip under the water box inlet) as did not see much water coming out side pisser. Took the pisser line off and was clear. Started ski with line off manifold and did shoot out water at manifold. Manifold and engine didn't seem too hot. Put pisser back on and tried again. Got up to 42.7mph then seemed to go to a limp mode. Took back in and engine seemed really hot this time.

We did change out fuel, fuel pump and new plugs. Took back in and ran on hose seemingly ok when flushing out. So the syptoms are:

1. Seems to rev limit without engine being hot taking off trailer
2. Would not run initially past 30
3. Side pisser did not seem to put out a lot of water... almost none at times, but when stopped to check, did put out at idle
4. Got up to 42.7 mph, but seemed to go into some tyoe of limp mode and engine seemed hot.

Checked oil after all of this and it was clean. Checked injectors while cranking, seemed even acoss all 4. not sure on pressure and will have to consult manual. Cranks and runs ok at idle.

My guess is maybe a clogged fuel filter that was semi cleared when revving, but not enough to run properly at higher rpm, but does not explain the heating up. I assume maybe a thermostat? Might explain the low pisser flow? Any help is greatly appreciated.

[meangreenman]

No thermostat in 12F.
30 or 42.7 mph is way too fast for LIMP home mode which is more likely 5 mph.

If you don't want to do a shotgun-repair, you should get a working dash meter and find out if there is any active error code being registered. Or hook up to KDS program and analyze ECU's stored data for error codes.

Meanwhile measure the fuel pump output and/or volume and compare the result to what's in the manual.

There is sock filter at the bottom of the fuel pump and inline filter at the fuel line on the ski. Also, each injector has a screen filter as well.

The ski might be in SLO mode.
What's the maximum rpm at WOT?

[leejax01]

Thanks for the reply. You are right in saying he needs a display, but these seem far and in between. Know anyone with one for purchase? Can't figure the rpm without the gauge. I will pass the info on. I do believe it is a fuel issue as it showed on the trailer before maybe even a cooling issue. I personally cleaned the tank and got a great replacement fuel pump with clean sock, but was running the old filter that was maybe a few years sitting/ old. I was glad the engine didn't have any issues afterwards that we know of at this point. Did read the manual and saw the 67ml flow at 3 seconds on the start button. Could there be a water flow issue? Any common spots to look for?

[meangreenman]

It can't be the overheat issue which would make the ski to go in 5 mph limp home mode.
The ski goes faster than 5 mph.
It's got to be something else like fuel issue.

[leejax01]

Well, took it back out today and did the same thing. So not the filter.

It starts and runs on the water hose no problem with water coming from side pisser
It runs on the water great for the first few minutes then starts to slow down until it gets to seemingly limp mode.

Need a display to see what is going on. Anyone has one for sale?

[Shuswap]

Cooling problem: Page 9-2 in the manual....part # 5 cooling pipe. Corrodes internally and cuts off the flow of water. Common in this vintage ski. Not sure if this is your water-flow problem and it's not easy to see....tucked right up under the intake manifold. I have a photo I could email.

Power: Are the plugs all firing all the time. These skis lose power when a plug quits in a similar manner. They seem to be running sorta....but won't reach any upper RPM.

Try to avoid damaging the engine due to overheating and you'll get this figured out with solid diagnostics.

[leejax01]

Tried to figure the cooling last night with the exhaust flow diagram, but these lines are hard to get to much less take loose and check the plumbing in reality. Will take loose the air box and see where that takes me as to what I can start checking. I will also do a compression test to get good numbers, but compression seems good. Not sure on the spark firing, but did put in new plugs initially. At 10 bucks a pop, we can try removing one at a time with a another new one and go from there I guess. I need to find where the water exits or where I can get to it and disconnect to see the flow and go from there backwards until I find the clog if it has one. Looked through the manual last night, and figured some of it, but really tight in there to disconnect anything. Is the side outlet to be expelling water when it is in the water? It does it on the hose, but not as much as when running. Looking for a gauge as that may help to figure it out.

I rode it with the seat off both times keeping an eye on it while he rode my ski just in case.