Other How Does a Return Line Make a Ski Run Poorly

[naticen]

I had some problems with my stock FX-1 dying a couple weeks ago. Every time I would do a sub or fall off, not even inverted, it would barely run and usually cut off while I had to feather the throttle to try and keep it alive. It would run perfectly fine except for that 10-30 seconds of starving after a sub or falling off.

I didn't do any diagnosis on the water, but when I was flushing the ski, I noticed the return line was broken in half. I swapped it for a new one and all problems are cured now. I don't get how the return line can affect how the ski runs?

 

[restosud]

lost pressure in the tank.

 

[Matt_E]

Returning fuel to the tank pressurizes the tank somewhat. Without that, it will run like chit. Same thing happens when you forget to put the gas cap back on.

 

[naticen]

I never knew that. I always thought that the only thing that needed pressure was between the fuel pump and the return restrictor. I guess the fuel pump needs all the help it can get.

 

[special fx]

not to mention it's dumping gas into your engine compartment while running, which also makes it run like crap.

 

[tshank123]

not to mention it's dumping gas into your engine compartment while running, which also makes it run like crap.

This is the main reason. It runs way too rich with the fuel vapors its sucking instead of fresh air.

 

[surfjunkie]

but he said it ran perfect except for after a fall. wouldn't, based on all those explanations, it run crappy all the time not just after a fall?

 

[Matt_E]

Maybe it didn't break until he fell, I don't know. In my experience, it runs bad even with the hood off, so I don't think it's mostly vapors.

 

[naticen]

It was definitely multiple times that it ran terrible after a fall and then ran great for a minute or 10 until the next fall. I guess none of them explain it fully. I was thinking originally that the split fuel line was like the hole in the siphon bilge elbow to keep water from siphoning into the ski. It let the fuel lines drain back away from the carb.

 

[kx454]

not to mention it's dumping gas into your engine compartment while running, which also makes it run like crap.

Think before you speak.

I do not believe any of the theories in this thread. I do not buy for a second that a non pressurized tank will make the ski run like crap. My ski has an open tank vent line and has always ran like a champ. Sounds to me like you are sucking water...

 

[Matt_E]

Think before you speak.

I do not believe any of the theories in this thread. I do not buy for a second that a non pressurized tank will make the ski run like crap. My ski has an open tank vent line and has always ran like a champ. Sounds to me like you are sucking water...

Every now and then I've left the cap of a cart tank (several different tanks over the years). Always runs like , right away, water or not.

 

[madscientist]

mine runs like crap when the tank vent goes bad.

 

[MADMAT]

I can feel both types of "crap running"....vapors....and no tank pressure. Once in a while my tank valve pops off (and makes its way into my pump dump 1 way valve :soapbox: renders me screwed if I break down...but I fixed it with a safety strap now!) and I can tell instantly. Then if I keep riding and do a roll I feel the spilled fuel get sucked in...on top of the loss of pressure

 

[kx454]

Every now and then I've left the cap of a cart tank (several different tanks over the years). Always runs like , right away, water or not.

Strange, I will have to see if it makes mine run poorly....that's a new one to me

 

[tshank123]

Think before you speak.

I do not believe any of the theories in this thread. I do not buy for a second that a non pressurized tank will make the ski run like crap. My ski has an open tank vent line and has always ran like a champ. Sounds to me like you are sucking water...

Disconnect your return line and let the fuel dump into your engine compartment. Report back with the results.

 

[XJCrawler]

Think before you speak.

I do not believe any of the theories in this thread. I do not buy for a second that a non pressurized tank will make the ski run like crap. My ski has an open tank vent line and has always ran like a champ. Sounds to me like you are sucking water...

If your going to call someone out like that, at least know what your talking about. A ski will run like with no pressure in the tank

 

[Joker]

If you keep having this problem and none of these other solutions work, put a second vent on your tank. I have seen a few threads where people have this problem and putting a second vent fixed their problem.

 

[Midlake Crisis]

If you keep having this problem and none of these other solutions work, put a second vent on your tank. I have seen a few threads where people have this problem and putting a second vent fixed their problem.

Are you talking about doubling up the check valve or running two separate vent lines? Where would you install the second one?

 

[Joker]

Are you talking about doubling up the check valve or running two separate vent lines? Where would you install the second one?

Run another vent line. Drill a hole and put in a barb fitting. I think this came from factory pipes website also. I can't remember who found it but it works.

 

[naticen]

This was definitely not caused by water. The only thing that I did was replace the return line and it is back to normal. I have since done bigger stabs, subs, and falls and have no problem with water through the motor.

Now that I think about it, it was a little sluggish overall, probably from vapors. It is due for a carb rebuild, and when I say it is running great or normal, I just mean for this particular ski. I still don't quite understand why it would make it run completely terrible, similar to sucking in water, for the first bit. I'm still thinking that check valves in the pump aren't quite sealing and it is letting fuel drain back with a break in the return line.