Fuel return line

[Bigredram87]

Hi Guys quick question on my 97 gsx. I took my carbs off to clean them a few weeks ago and when I pulled the return line off very bad dark brown gas came out of hose. I was curious if this was normal and the carb doesn't use the return very often so it has been stuck in there for a very long time? These are not gray lines btw they are black automotive.

 

[mikidymac]

The return line should be flowing whenever the ski is running.

 

[Bigredram87]

The return line should be flowing whenever the ski is running.

Ok well what would it mean if this line is not flowing? Carbs passed all pressure checks perfectly all clean carbs were not that dirty, good clear gas going in so I can't imagine that old dark brown gas is flowing right through, it seems that the gas has been in that return line stagnant for a long time. Now I will admit I am struggling with a performance problem with this ski I'm getting max speed 50 when I used to get about 57. If I replace that return line with a piece of clear, should I see constant flow of gas ?

 

[Bigredram87]

Ok well what would it mean if this line is not flowing? Carbs passed all pressure checks perfectly all clean carbs were not that dirty, good clear gas going in so I can't imagine that old dark brown gas is flowing right through, it seems that the gas has been in that return line stagnant for a long time. Now I will admit I am struggling with a performance problem with this ski I'm getting max speed 50 when I used to get about 57. If I replace that return line with a piece of clear, should I see constant flow of gas ?

One other point I just realized that my vent and return lines were switched at the baffle I hooked the up wrong. Is it true this doesn't actually matter on a 97 gsx.

 

[Fishnut]

I just dealt with this problem today. The carbs are not getting all the gas they want due to no circulation and fighting a closed system which would make me suspect an air leak since it will run. It is like not opening the vent screw on an outboard motor. I would take the return line off and clean it or replace and I bet it will see 57 again

 

[Bigredram87]

I just dealt with this problem today. The carbs are not getting all the gas they want due to no circulation and fighting a closed system which would make me suspect an air leak since it will run. It is like not opening the vent screw on an outboard motor. I would take the return line off and clean it or replace and I bet it will see 57 again

Great advise thank you, I took my fuel lines off blew through them, I also connected the filter directly to the reserve to eliminate possibly clogged selector. I am going to replace the return line with clear so I can see if it is flowing today. Basically what your saying is because my carb is starving for fuel there's not enough in there to cycle through the return? Also when I replace the return line at idle I should see a full line? As far as fuel tank pressure goes I believe I am fine my gas cap always hisses when removed and if I leave cap on after running and remove fuel separator I get fuel flowing in until I remove gas cap.

 

[Fishnut]

Bypassing the selector valve till the problem is figured out is a good idea. And yes the line should be full of gas after it has had a chance to purge. Hit me back after you have tested this.

 

[Bigredram87]

Bypassing the selector valve till the problem is figured out is a good idea. And yes the line should be full of gas after it has had a chance to purge. Hit me back after you have tested this.

Thanks fishnut I did take the ski out today and the clear return line does help, it is circulating fuel good now, I am still fighting my low top end issue I'm topping out at about 6500 rpm perfect compression rebuilt carbs , rebuilt water valve cleaned rave valves. New plugs gapped proper...... I can't quite figure it out my max speed is about 50, it has great low end power just doesn't feel the same top end , God speed is about 7 mph less than last year , I do however have a top loader on it now which I know should affect it slightly . I may swap out just for testing

 

[Fishnut]

hope removing the top loader is the answer and to me it would be worth 7mph