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99 GSX Limited Return Fuel Line Restrictor?

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A6BN

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I replaced the fuel lines on my 99 GSX limited at the end of last season. Ran great prior to fuel line replacement. I went to start the ski for the first time this season and it is only running on one cylinder (the forward one). It appears I am not getting fuel to the rear cylinder. Does the GSX limited have a fuel return line restrictor? If it does and this restrictor is missing would it starve the rear carb of fuel? The manual mentions a Fuel Return Line Orifice of .031 inches but I'm not sure if this is something in the carb or in the fuel line. Any help would be appreciated.
 
Hi & welcome to the forum.

I'm interested in this question also.

I assume you mean at idling. how did you determine this?

Some motors run on only one cylinder at idle.....I don't know which....maybe they all do or maybe none of the newer skis do, IDK?????
Someone will reply with the right answer soon.
 
The item is in the return line. Most do not even know it exists and never replace it and have no running complaints.

Are you certain you have all the lines in the correct location?
 
1. there is no restrictor.

2. this is a carb ski, so it will run on both all the time

3. how did you determine that it's running on one?
 
While the ski is running on the trailer, I pulled the mag cylinder plug wire and the engine died. I pulled the PTO cylinder spark plug and it was completely dry, no carbon or sign of combustion. I have good spark to that cylinder.

What is this fuel return line orifice (.031") mentioned in the manual?
 
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I've never heard of that, nor anything in the manual referred to in inches.

I'm wondering if the filter in the PTO carb is clogged. Something may have been dislodged when you changed the fuel lines.

I would remove the carbs and inspect the filters inside of them.

the fuel line return simply moves fuel back to the gas tank when demand is less than what's being delivered.

I am not aware of any reason to restrict it.
 
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My understanding is all of these have factory restrictors of some type somewhere in the fuel return, unless the return is blocked off, which is also possible depending on the fuel pump design, like when using the Walbro pump for instance. But that's another subject for aftermarket performance tuners and shouldn't apply in the case of a factory stock ski.

Regardless, a return fuel line restriction won't be responsible for no fuel to the cylinder, like a stuck metering valve or hole in the diaphragm or clogged internal filter would.

A cylinder that's not being fueled is also a cylinder that's not receiving lube, so don't run the engine hoping it clears itself up by some stroke of luck, shoot a small amount of oil like a table spoon full in the cylinder through the plug hole and some into the throttle bore because dry is not good, pull the fuel system apart and rebuild those carbs to find out where the fuel obstruction is, new fuel lines and the whole nine-yards if not done already. You might have sticky/gummy fuel inside the carb or a internal blocked filter, you won't know until it's taken apart and carefully examined.
 
One thing you might try if you're absolutely certain the fuel system is gum and trash free (rarely the case if the ski is more than a few years old, it will need a going-through) is to put your hand dierctly over the carb intake that's not fueling while the engine is running and block air from entering much as the choke plate would do, sometimes a stuck metering needle can be unstuck this way.

I'd bet though, the carbs need help.
 
One thing you might try if you're absolutely certain the fuel system is gum and trash free (rarely the case if the ski is more than a few years old, it will need a going-through) is to put your hand dierctly over the carb intake that's not fueling while the engine is running and block air from entering much as the choke plate would do, sometimes a stuck metering needle can be unstuck this way.

I'd bet though, the carbs need help.

Thanks to all for the replies.

I tried blocking the air intake off. No luck. The pto cylinder will run if I pour fuel/oil mixture into the carb intake. It's looking like I will have to take the carbs off and rebuild. Not looking forward to that. Any advice? I've never done it before.
 
Check out the sticky at the top of the news feed by Bill86e. Just take your time and make sure you blow through every little passage. The carb filters are the most important and must be clean. Set out a couple paper towels and have one area for dissassembling/cleaning, then place the clean ones on the next paper towel for re-assembly. Do one carb at a time, that way if you mix something up, you can take a look at the assembled one and find out for sure. There should be no guess work with these.
 
"The pto cylinder will run if I pour fuel/oil mixture into the carb intake"

Yeah, that's a good sign it's not fueling that cylinder if you place your hand over the choke plate it almost has to pull fuel through the chamber. If it's run with a dry carb for long, the cylinder will be damaged so it looks like you have no other choice than to just dive in and start turning wrenches.

Just to clarify the image in my head is synchronized, I'm under the impression we're discussing the 951 motor.

"Any advice? I've never done it before."

The hardest part really is getting them on/off IMO, and you've done that with the fuel line replacement. Teardown and cleanup you're not leaning over upside down and backwrds with a mirror ans flashlight and it's really not all that complicated, purge plenty of carb cleaner through both brass jets to dissolve gum in the passages and watch on the inside of carb bore as the cleaner shoots through all the passages to make sure they're clean then chase the solvent with compressed air if you have a compressor, hope you do but you might get away without one if you get liberal with the solvent.
 
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