SJ reserve runs fine ON leans out

[Fourtraxjay]

Yes I searched.

Before I dig into this hoping you riders w experience may know exactly what to look for first.

Bone stock 2017 SJ with maybe 10-15 tanks of fuel through it. Has run flawlessly until recently after it sat for 2 weeks.
Full tank of fresh full, water separator drained and dry, fuel filter looks fine.

When I have fuel selector in ON position it starves for fuel under load or top speed and dies. Runs perfect when selector is at Reserve setting.

Are there filters in the tank on the fuel pick ups?
Do fuel selectors ever get dirty/clogged?
The machine is like new so I doubt any lines will have cracked.
I’m going to check all the fuel line clamps carefully but initial inspection didn’t show any obvious lose lines

Thanks for any insight
I’ll post the solution when i find it.

 

[orangefinger]

how full was your tank when u tested this ?
what where u doing when u rode last ? like a bunch of subs ? fountains ?
my guess at this point would be
A) u got water in your tank ....drain refill with fresh
B) fuel selector or pick up defect or clogged...take of line blow thru make sure its open

 

[Fourtraxjay]

Thanks for the reply.
Tank full to the top.
It was running fine before it sat for 2 weeks.
I was riding normally... I just learnt to sub it this weekend.... so problem sterted before those:
Fuel is lighter than water and water will sit st the bottom of the tank so water in tank theory would make more sense if I was having problems on reserve (lower pick up )
I found one of the zip ties holding the fuel lines and wiring harness from the tank to selector switch pretty tight so I’m thinking it may have been pinching the line, (Not the zip ties that ‘clamo’, one that holds it up for routing)
I’ll find out today if lossening it helped, if not I’ll pull fuel pick ups and start blowing...lol

I’ll report back with findings.
Thanks again

 

[bernard]

My 2013 model is doing this as well.

 

[Vumad]

I know my X2 has filters on the pickups. I can't recall if the stock superjet has them but I would speculate it does. Yes they get clogged.

If you are holding it WOT, and you think it is running lean, and it is shutting down at WOT, you might be seizing the motor. You should stop holding it WOT if you think it is lean.

Common problems other than clogged lines, which would have to before your fuel petcock (your fuel filter is after) is a failing petcock that is letting air in or bad fuel lines.

The easiest way to test the petcock is to bypass it. Just hook the "on" line directly to the carbs and see if the problem goes away.

Stock fuel lines are awesome and rarely leak. Even without zip ties they can hold a tight seal to the fittings. Non-the less, you can check for damage to the lines and replace the zip ties at the connections. If you have after market fuel lines, the clear type suck and break down. OEM are much better, or @JetManiac sells an OEM replica in grey that is as good as stock (or so I have been told).

You can also test your theories and fuel lines by switching the pickups at the tank. Just swap the two lines and if your selection problem reverses then you know the problem is from the tank.

 

[Baja 252]

Since the Reserve system works fine, you know that the issue iswith the "ON" system. It's either the "ON" fuel pick up, ON lines or fuel switch.
#1 Remove the clamp on the fuel tank and take out the fuel pick-ups and check to see if it's blocked. Remove the shield by removing the cotter pin and shield, the ON line is the short one.
#2 While the tank is open check inside the tank for debris.
#3 Remove the fuel switch and take it apart and check for blockage (they are prone to do this).
#4 Blow thru the ON line from the switch to the pick-up (out of the tank) to be sure it's not blocked.

If you find any foreign objects that blocked anything clean out the Reserve circut also because it most likley has debris in it also.

 

[Vumad]

Sidebar since water in the fuel was mentioned...

I used to run 93 octane with ethanol (ADA head with compression. I was progressively displeased with the performance of my ski. I cleaned my carbs many times and tried many other things and was never happy like I was when it was first setup. The place I used to get ethanol free 93 stopped carrying it and the ethanol free at wawas is only 89.

I switched to a blend of (for a 5 gallon mix)
4 gallons of 89 ethanol free
1 gallon of 110 race gas
2.5 oz of sta-bil storage
45:1 yamaha lube.

My ski runs sooooo much better than it did with 93 ethanol-mix.

Ethanol pulls moisture from the air, among many other issues that are just not positive for us.

 

[Fourtraxjay]

Solved!


I started with a blow test from tank pick ups to carb feed and noticed the reserve would flow more than the ON side



I disassembled the fuel selector switch and I found a few water droplets inside. Blew them out and blew out both lines from tank to carb and all is good now. Also added a 1/4 can of sea foam fuel treatment to help with any other droplets still lingering.

There are no screens or filters on the pick ups in the tank by the way.

Thanks for the input people.

J