ok I'm ready to give up..

[scotty6336]

Hey guys, hate to look for help like this being such a new member, but I've done some reading and "restored" my new to me 96 GTX and GTI, but now I'm having an issue I can't figure out.

-The GTX is great. I've followed all the advice here and other places, replaced all the fuel lines, the starter, seat cover, guage LCD plastic, etc, and it literally runs like brand new.

-The GTI, on the other hand, is giving me fits. It ran (as in started quickly and revved fine on the trailer with the water line) but the carbs filters were full of gunk and the fuel lines were grey. So, I rebuilt both carbs and replaced all the lines, put fresh gas in it, and now it seems the pump won't pull fuel, all the lines are dry.

I've triple checked the fuel line routing against my will, and its all correct. I thought maybe I reversed the fuel in/out lines to the carbs amongst other mistakes, but I am now 100% sure its ran correctly. If I dump gas in the carbs, she'll fire right up and run a few seconds. I've done this probably 20 times on pre-mix trying to get the pump to pull, but still, nothing.

I even thought mabe the fuel baffle was pinched (as in I tightened the clamps too far) but this is also not the case. I've also ran my air line into the fuel in line AND out line to/from the carbs, and it'll run through cleanly, or so it seems....If I give it to much pressure it'll blow off the fuel filter jug, and I can't recall which line I was pumping air in when that happened.

Any ideas? could the fuel pump just be weak? I consider myself a pretty good mechanic and have been building jeeps for a few years, but this is still fairly new to me...Any ideas would be appreciated.

Scott

 

[scotty6336]

EDIT: I should also mention the pulse line is connected and she turns over fine

 

[Coastiejoe]

It really does sound like you have the lines crossed. Be patient, someone will be able to get you back on track.

 

[scotty6336]

Maybe, and I hope so. I'll be out of town this weekend but my wife is still questioning my "junkyard purchase" lol...I need to get her on the water soon!

I did try reversing the intake/return carb lines and started it by putting some gas in the carbs to make sure I wasn't losing my mind, but nothing came of it.

 

[Bnelson]

Hmm.... I know this isn't the most approved way out there, but u can put just a little compressed air to the return line and it should push fuel up to the carbs... Notice I said a little air, do not let it rip full blast... And just for the sake of everything, check the lines one more time and make sure the pulse line is in the correct spot.... If all is correct and fuel is at the carbs and you still have nothing I would look at the diaphragm on the pump side of the carbs.... When rebuilding the carbs did you use genuine Mikuni kits or aftermarket... Mikuni is the only way to go as many people have had trouble right out of the gate with non Mikuni kits


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[scotty6336]

Hmm.... I know this isn't the most approved way out there, but u can put just a little compressed air to the return line and it should push fuel up to the carbs... Notice I said a little air, do not let it rip full blast... And just for the sake of everything, check the lines one more time and make sure the pulse line is in the correct spot.... If all is correct and fuel is at the carbs and you still have nothing I would look at the diaphragm on the pump side of the carbs.... When rebuilding the carbs did you use genuine Mikuni kits or aftermarket... Mikuni is the only way to go as many people have had trouble right out of the gate with non Mikuni kits


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Well, on the air line trick, I tried that. Turned on my compressor and after running the air into the return line, with the line pinched as to not flow too much pressure, the fuel line would barely dripple any gas at all, and eventuall wouldn't flow any. It was at that point that I thought maybe it needed more psi, and then the screw-on fuel filter thingy blew off with a loud pop.

As for the carb kits, I got them off ebay, bought two, and they were both $35.00, but I honestly can't say if they were genuine Mikuni or not...but seeing as the ski will fire up with gas dumped in the carb itself, the carbs must be functioning correctly right?

 

[kicker]

Not to be smart, but is your selector switch "ON". If so, I would start with the fuel pump side of the carb (I believe its a single lunger) and be sure its all correct. Mainly the diaphragm and check valves. Mikuni kits are the best, if something else was used they have been known to have some substandard parts once in a while.
http://www.mikuni.com/pdf/sbn_manual.pdf

 

[Bnelson]

Well, on the air line trick, I tried that. Turned on my compressor and after running the air into the return line, with the line pinched as to not flow too much pressure, the fuel line would barely dripple any gas at all, and eventuall wouldn't flow any. It was at that point that I thought maybe it needed more psi, and then the screw-on fuel filter thingy blew off with a loud pop.

As for the carb kits, I got them off ebay, bought two, and they were both $35.00, but I honestly can't say if they were genuine Mikuni or not...but seeing as the ski will fire up with gas dumped in the carb itself, the carbs must be functioning correctly right?

Kicker nailed what I was trying to say with the aftermarket kits, and yes def check your selector.... And no just because it starts by pouring gas down the throat of the carb doesn't mean the carb is ok, at the point your basically bypassing the carbs because your putting fuel straight into the motor.... It's weird that the gas stopped flowing even with pushing air to it... Maybe someone else can chime in on that.... But yes I would definitely have a look at the pump side of the carbs again....


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[kicker]

..but seeing as the ski will fire up with gas dumped in the carb itself, the carbs must be functioning correctly right?

By dumping gas in the carb, you are essentially bypassing the carb. Anyway you can post some pictures of your fuel lines. Much easier to troubleshoot the routing if that is the problem.

 

[Sportster-2001-951C-Stock]

Hmm... Sounds like it may not be pumping fuel? I'm wondering if maybe you replaced the two mylar check valve disks in the fuel pump body and they aren't sealing? These two disks typically aren't flat (a small amount of "curl") and so it's sometimes necessary to make sure the concave side is facing down toward the pump body casting, b/c the mylar film these disks are cut from is rolled up onto a roll as it comes off the manufacturing line.

Here's a description of what to look for and be aware of while orienting the check valve disks in the fuel pump body:

 

[scotty6336]

ok well good points made....I replaced the fuel selector switch at the same time as the fuel lines (I've tried this on "on" "reserve" and "off" to make sure my fuel line routing was correct.. I guess its possible that the switch is plugged. From what Kicker said, I guess I'm just bypassing the carbs..(when I said I was new to this I should have mentioned new to 2 strokes as well) I'll get some pics up next week when I get back home to see if that helps.

The baffle deal that goes into the tank, could it be possible that when removing it I F'd it up? I pulled the whole tank and cleaned it out so that could be an issue as well.

 

[LouDoo]

It could be a check valve in the carb(s), try this run a line from the intake of the mag. side carb. directly to a gas can. It the ski starts there's a problem in the fuel delivery system, if not you have a problem in one or both, probably the mag. side carb. Dumb question, have you checked for spark?

Lou

 

[kicker]

ok well good points made....I replaced the fuel selector switch at the same time as the fuel lines (I've tried this on "on" "reserve" and "off" to make sure my fuel line routing was correct.. I guess its possible that the switch is plugged. From what Kicker said, I guess I'm just bypassing the carbs..(when I said I was new to this I should have mentioned new to 2 strokes as well) I'll get some pics up next week when I get back home to see if that helps.

The baffle deal that goes into the tank, could it be possible that when removing it I F'd it up? I pulled the whole tank and cleaned it out so that could be an issue as well.

Highly unlikely its your baffle, unless you broke it in half. If one of the siphon tubes in the baffle broke off you would have felt it because it is one solid mold with the outer side of the baffle.

How full is your tank? Sorry but trying to get the simple stuff out of the way first.

 

[Sportster-2001-951C-Stock]

I'll add that if you disconnect the fuel line from the fuel pump, you should be able to blow air into it (this doesn't require much pressure) and hear the air bubbling from the submerged fuel pickup inside the fuel tank.

Edit: That is, assuming there is no check valve installed in the fuel line connector at the fuel tank, mine didn't have one.

 

[scotty6336]

Well I didn't mess with the fuel pump, all I did was replace the fuel lines, clean the tank, and rebuild the carbs. I'm starting to think the carbs might be the issue but I can't imagine what I did wrong, I was incredibly anal to make sure all the parts were in the same place, I did them one at a time from the diaphragm to the filters.

 

[scotty6336]

I'll be trying this next week and get back on the thread incase anyone else has this issue

 

[scotty6336]

Highly unlikely its your baffle, unless you broke it in half. If one of the siphon tubes in the baffle broke off you would have felt it because it is one solid mold with the outer side of the baffle.

How full is your tank? Sorry but trying to get the simple stuff out of the way first.

How full does the tank need to be?? Could this be something that simple? I put about 2 gallons in it, I would've put more but in the off chance (LOL) that I F'd something up, I wanted a light tank to remove. Should I add more gas??

 

[scotty6336]

It could be a check valve in the carb(s), try this run a line from the intake of the mag. side carb. directly to a gas can. It the ski starts there's a problem in the fuel delivery system, if not you have a problem in one or both, probably the mag. side carb. Dumb question, have you checked for spark?

Lou

I have good spark, I'll run that line next and touch base back

 

[soccerdad]

Two ideas. First, is there gas in the water separator? It is the filter thing in the front hatch. It is the first place the gas goes when you are sucking it from the tank to the motor. If is not there, then it wont be making it to the carbs. Note that it is sucking the gas a long way so any vacuum leak in the delivery line, could keep gas from flowing. Make sure the water separator bowl is firmly attached. Then, if you have a vacuum brake bleeder, (mitivac, or one from harbor freight $18.00) then hook it to the line going to the carb and see if it will pull the gas in. I put an inline fuel filter about 10" from the carb, so I use the hand vac to suck the gas all the way to the filter, then quickly connect the hose to the filter when you get it that far. The fuel has a long way to go so the motor has to crank a long time to get the gas there. I know when I first tried with the hand vac I found it was not getting me gas and that the water separator was leaking air. The hand vac us really helpful in finding this type of issue.

 

[scotty6336]

Two ideas. First, is there gas in the water separator? It is the filter thing in the front hatch. It is the first place the gas goes when you are sucking it from the tank to the motor. If is not there, then it wont be making it to the carbs. Note that it is sucking the gas a long way so any vacuum leak in the delivery line, could keep gas from flowing. Make sure the water separator bowl is firmly attached. Then, if you have a vacuum brake bleeder, (mitivac, or one from harbor freight $18.00) then hook it to the line going to the carb and see if it will pull the gas in. I put an inline fuel filter about 10" from the carb, so I use the hand vac to suck the gas all the way to the filter, then quickly connect the hose to the filter when you get it that far. The fuel has a long way to go so the motor has to crank a long time to get the gas there. I know when I first tried with the hand vac I found it was not getting me gas and that the water separator was leaking air. The hand vac us really helpful in finding this type of issue.

Well no, the fuel won't even reach to the water separator, it's bone dry. I'll get a pump and try to manually pull the fuel through the lines....This has GOT to be something stupid simple I'm thinking

 

[kicker]

good points soccerdad. The water separator also should have a good O ring, if its missing or severely cracked/damaged that will be a problem. I would add another gallon or 2 to that tank as well, just to be sure it is well past the reserve suction tube.

 

[manolocross]

If the fuel filter bowl blew apart it's done... Don't try to reuse. This will be a major air leak in fuel line and can be the reason why no fuel is pumping. Maybe previous owner cross threaded it???


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[Minnetonka4me]

I would run a temp line from reserve nipple directly to the carb in. If it doesnt suck gas theres something wrong with the fuel pump or the gaskets in that area.

 

[scotty6336]

I would run a temp line from reserve nipple directly to the carb in. If it doesnt suck gas theres something wrong with the fuel pump or the gaskets in that area.

This is the only thing mentioned that I haven't tried yet, and I've got all day tomorrow to get this thing going. The pump should be good though as the ski ran well before I swaped the lines out.

One more question though....If there was a crack in my fuel tank would that somehow prevent fuel from being drawn through the lines? I ask b/c I cracked the fuel filler spout while removing the tank. I repaired it, but after closer inspection last night it did not hold. I'm going to pull it again tomorrow am and use a two part panel bond we use here at my body shop to seal it up, but I'm wondering if this could have been the problem all along?

 

[soccerdad]

The fuel is sucked from the tank to the pump through the baffle. So a crack in the tank would not have anything to do with it. Now a cracked baffle could let air in. I would try the line directly to the reserve nipple on baffle and see what it does. Have you tried using a hand vacuum yet? It is MUCH easier than trying to pump with the motor turning. If it gets gas to the hand vacuum, then the fuel supply side is good. If you cant pull it to the hand vacuum, then you have a leak in the supply side. you could even drop a line into the bottom of the tank and bypass all of the baffle, etc. That has got to work. Then if you still have issues pulling gas in, it is on the pump side.