- Location
- Lakewood, CA
@amitchell Did you ever find out what was going on? Ive been fighting a similar issue with one of my motors, no matter what I do I cannot get the front cylinder to run rich its always lean and I've seized it twice.
Super Jet Dual 38 fuel delivery problem?
- Thread starter amitchell
- Start date
OCD Solutions
Original, Clean and Dependable Solutions
- Location
- Rentz, GA
Is there a chance you guys are running the front cylinder cooler due to your water routing?
Running the line direct from the front of the head to a pisser offers very little restriction and could be a concern.
Running the line direct from the front of the head to a pisser offers very little restriction and could be a concern.
- Location
- Lakewood, CA
Mine is setup for dual cooling with ADA head (185psi) dumping the front line without restriction. It never ran cool it was always pretty warm. I am starting to put valves on my skis and restricting water for cool water riding but when this happened it was middle of summer water temps were up. No matter what I did I could never get the front cylinder to fatten up. Rear was not a problem I could get it as rich as I wanted by turning the high screw out.
I ran staggered jetting (145 main up front), external fuel pump feeding each carb, different carbs, and it would still run lean. (going by plug readings and piston wash) It was on the edge so it would last for a while and run great but eventually would seize.
Leak test passed every time and didn't lose any pressure. Ive been over the fuel system multiple times and cannot find anything. My next step is to tear it down go into the bottom end an see if I can find anything. I haven't tore it down that far since I had rebuilt the whole motor and started having this problem.
I ran staggered jetting (145 main up front), external fuel pump feeding each carb, different carbs, and it would still run lean. (going by plug readings and piston wash) It was on the edge so it would last for a while and run great but eventually would seize.
Leak test passed every time and didn't lose any pressure. Ive been over the fuel system multiple times and cannot find anything. My next step is to tear it down go into the bottom end an see if I can find anything. I haven't tore it down that far since I had rebuilt the whole motor and started having this problem.
- Location
- Victoria BC
I am pretty much in the same situation, I am fat enough in the front where it is not an issue now. However it pisses me off that I don't know the reason for the difference. I am restricted and have temp monitors everywhere, I keep a keen eye on things.
I did not try pumping fuel to each carb individually...
My motor has about 25hrs on it since a fresh rebuild (top and bottom). It runs like a champ, so it will stay as is.
- Location
- Lakewood, CA
Be careful if its on the edge like mine it will seize. Can you get the front cylinder to run rich? Mine was running great until it seized.
I wont be happy until I can see the front cylinder real rich and then dial it back. I did get lazy with it and just ran it last time with the staggered jetting but it eventually seized. (probably 15-20 hours) Ive never seen this problem with any other ski I own. Right now my superjet is running on my stock 61x spare while the other sits on the bench.
I wont be happy until I can see the front cylinder real rich and then dial it back. I did get lazy with it and just ran it last time with the staggered jetting but it eventually seized. (probably 15-20 hours) Ive never seen this problem with any other ski I own. Right now my superjet is running on my stock 61x spare while the other sits on the bench.
- Location
- Granbury, TX
My motor setup is almost identical to yours. I cooked my front piston in a very similar matter... Motor was pressure tested as well. However, when I pressure tested my CARBS, the front carb (dummy) fuel pump plate leaked around the entire perimeter. It was enough to lean out the fuel flow to the front chamber and cook my piston. Always pressure test your carbs.
- Location
- Lakewood, CA
I just pressure tested the slave carb with the mikuni pop off pump and on the gauge pressure isn't holding. It isn't leaking from the carb body or the needle seat. Where can the pressure be going? Ill have to investigate more tomorrow.
- Location
- Granbury, TX
See the attached pic. I'm willing to bet it's in the area shown by the red dotted line. Spray the carb exterior with soapy water and look for bubbles.
- Location
- Lakewood, CA
I checked around there with liquid leak detector and saw no bubbles.
- Location
- Granbury, TX
What is liquid leak detector? I'd say keep looking, if it isn't holding pressure it's leaking somewhere... It should hold 10 psi just like a motor, for at least 10 minutes....
OCD Solutions
Original, Clean and Dependable Solutions
- Location
- Rentz, GA
It's really expensive, professional grade, little bit of soap and water in a bottle. 
http://www.toolfetch.com/snoop-leak...Y9u8WQuo0YmYarDKNk5Eeh7Ptrq7GIQTO0aAvOl8P8HAQ
http://www.toolfetch.com/snoop-leak...Y9u8WQuo0YmYarDKNk5Eeh7Ptrq7GIQTO0aAvOl8P8HAQ
- Location
- Lakewood, CA
That's what I used, got lots of it at work. For my test I crimped a piece of tubing on the return side and might have made it too long and the pressure was slowly seeping by the restrictor. I was in a hurry to test before work, I will test it again tomorrow.
Don't think this is the issue. I have dual 1/2" cooling to my BB and dual 1/2" pissers with no restrictors and it runs great with dual 38s.
I have run single pump stock 38s setup on several BB with aggresive timing, etc. For years without fuel problems. It must be something else.
If you do add second fuel pump, remember that you will need to add second pulse to the cases and a return Y with a jet restrictor to regulate fuel pressure.
It should hold 20-30psi without leaking. I used to have more sealing issues until we switched to only oem for the rubber oring gaskets and our allen bolt kits allow easier tightening to seal as well.
Vumad
Super Hero, with a cape!
- Location
- St. Pete, FL
I have a similar setup. I re,oved my enhncer when it failed but changed nothing.
My popoff is 18psi
my front cylinder feeds the pipe, rear dumps unrestricted
i have dual cooling with 3 pissers. One rear cylinder, one pipe, tee off the pipe line nd after that i have flow control with pisser after flow control.
i have a concord 12/17 wot is 7200 rpm at 49mph
My superjet has single fuel pump, but my sxr is running dual fuel pumps.
Both skis setup by bad boys racing and run amazing
My popoff is 18psi
my front cylinder feeds the pipe, rear dumps unrestricted
i have dual cooling with 3 pissers. One rear cylinder, one pipe, tee off the pipe line nd after that i have flow control with pisser after flow control.
i have a concord 12/17 wot is 7200 rpm at 49mph
My superjet has single fuel pump, but my sxr is running dual fuel pumps.
Both skis setup by bad boys racing and run amazing
- Location
- Lakewood, CA
I just pressure tested the carb again and it's holding pressure with no leaks. I had a leak on the pop off pump connection the first time.
- Location
- Granbury, TX
Interesting.... Well at least that can be eliminated as a possible source of the issue. Is the front chamber still running lean?
- Location
- Lakewood, CA
Last time I had it out it was. The motor is out of the ski now on my workbench. Was planning on tearing it down and looking in the bottom end to see if I can find something. I donno where else to look I've been over and over the fuel system and electrical system.
