96hx at a loss

[bartandanika@westnet.com.]

Took my ski out it ran fine for 10-15 mins then motor seems to reduce to an idle ( throttle at full rev's ) , then picks up to normal capacity after a short time before reducing back to an idle. Then stops if you don't have full throttle on. Have changed all fuel lines, filters,cleaned carby etc.

PLEASE HELP WITH ANY IDEA'S

 

[Nate Surveyor]

Fuel supply problem. Gray fuel lines are usually the culprit. Clogged carb filters, and baffle filter, or fuel select valve. Clean out the fuel supply system.

For the immediate, you may try reserve, HOWEVER, lean conditions are the doom of 2 stroke motors. Lean conditions make it run too hot, and hot rings mess up the ports, and score the cylinders. So, don't ignore a lean condition. It means bigger trouble.

Nate

 

[matt79]

Hi Nate. I'll reply to your message to Bart as I have been helping him to try and get his HX going. He has completely stripped down the fuel system and rebuilt it. Fuel tank emptied and cleaned, check valves checked, fuel selector valve cleaned, all grey lines replaced, Inline filter bowl cleaned and a new extra inline filter added. Carbies stripped down cleaned, pulse pump line changed out. new rotary valve timed properly. We have run out of ideas. The ski was bought in pieces which Bart has rebuilt. When we start it on the trailer it runs perfectly. When we take it out on the water, it runs anywhere up to 45 minutes perfectly then suddenly dies down to what feels like running on one cylinder. Some times it starts again, some times it won't. By the time we get it home to try and identify the problem, it starts and runs like a dream. Hard to fix a problem that is never there when you want it to be! We are pretty sure that we have checked and fixed any fuel related problems, could these symptoms indicate an electrical problem? we are going to check that the regulator is not over charging the system. does the temp sensor on the top of the head shut down the MPEM if it gets a hot reading? what else could cause electrical problems?

 

[Nate Surveyor]

One last check, pressure check the carbies, and install a clear pc of tubing on the fuel return line, and look for bubbles. Also, a clogged vent will do just about what you describe. Runs great, until vacuum develops in tank. Loosen the gas cap (Don't loose it!) and see if you hear a FFFFF. IF you doo, well you have it.
Another stunt you can doo to see if it is fuel related, is to:
Take a full can of silicone spray, and duct tape it to the side of the doo. Within hands reach, with the left hand. Run a temporary tube down to the top of the spark arrestor screen, at the fogging hole. Now, next time she shuts down on you, reach down, and hit the spray of silicone. IF it improves, THEN you know it is fuel. IF it does not improve, then you know it is electrical. Timmy Boy has a method to check the electrical with a jumper. Also, there are little plugs you can place on TOP of the spark plugs, that have lights in them. When the plug fires, it lights up. Now, if you can run it with the seat off, nxt time she messes up, you can SEE the plugs and SEE if they are getting spark. At some point you have to corner the problem. Maybe even a trimming of the end of the spark plug wire, (trim 1/4") and re-install the boot, that goes on top of the plug.
Sometimes FINDING the problem is harder than FIXING the problem!

My philosophy is that if it was built, and designed by a man, then a man can FIX it!

Nate

 

[nswillin]

Hey Matt & Bart. Sorry about your troubles. Fuel system sounds to be alright if you have don all the things you stated. I'm kinda leaning toward over heating, but more towards a bad rectifer.

Try this, disconnect the red wire from the rectifier box and go run it. If it runs fine then the rectifier is your problem.

The rectifier couple of things. The rectifier receives AC current from the magneto and transforms it into direct current (DC). Then it converts that AC power to DC power. The red wire sends back to the battery, regulated DC voltage to keep your battery charged while riding the ski.
When the rectifier is bad, that red wire is sending AC voltage to the DC battery. Your ignition runs off DC power as it is a DC CDI ignition. When AC is sent, it messes with the DC CDI.

Go from there and see what ya got.

Ryan

 

[matt79]

Thanks for your replies. We will try those couple of things and see what happens. Keep the suggestion coming.
matt

 

[Nate Surveyor]

NS is right. I still have not figured out HOW to doo what he is talking about, but it sure sounds like it could help. Gotta get a place to down load the manual to.

N