Superjet not drawing fuel?

x2ryder

x2ryder

Location
Moline, IL
I have a 98 SJ with a 5mm stroker 165 psi, and a set of 48 Powerbombs. They are jetted with 132.5 pilot 140 mains, 2.0 n/s and a 95 gram spring. Took it out last night and couldn't seem to get it to run consistant. Always seemed lean Plugs look fine. But it seemed to be starving for fuel? Now it will start on the trailer with the primer but then dies. I look at teh fuel lines and they look like they don't have fuel running through them. Any help always appreciated.
Thanks
Cory
 
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SUPERTUNE

SUPERTUNE

Race Gas Rules
Location
Clearwater Fl.
Cory,
Just make sure the all fuel pump diaphrams are in good shape, no creases from like a backfire. Check the return bleeds to be clean.
I don't know a lot about the Riva Powerbombs, other than I didn't like them for freestyle engines setups, I think that they might make a good race carb though.
Just from experience that I have with big carbs is they need fuel off the bottom from the weak signal the low jet receives.
Put in a 2.3 needle valve, so you have some fuel pressure for the low jetting, then go to a smaller main, start at least 10 points. (130).
Probably need a bigger low jet as well...but not really sure because it seems to me you suffer from low cranking compression. Do you really know that's correct? Have you tried a different battery? Is your starter new? How about the battery cables? I'm thinking IF you do have 165 lbs cranking compression your going to be hard pressed to make those carbs work well.
 
x2ryder

x2ryder

Location
Moline, IL
Well that did not fix the problem either. I even jetted back to what Riva put in them. 150 pilot 135 main 2.5 ns and a 115 spring. Any ideas?????
 
A

ATS_Scott

X
Location
Corinth, TX
Check your lines and filters for holes, and verify your low speed screws are actually open. Open them a turn and see if it will pump fuel. And get some clear lines if you don't have them.
 
SUPERTUNE

SUPERTUNE

Race Gas Rules
Location
Clearwater Fl.
Did you follow the instructions I gave you?
If yes,
What results did you get?
Where are the adjusters set at?
I recommend to start at 1 1/2 turns out for the low and 1 turn out on the high.
When you went back to the Riva setting did you try the 95 gram spring?
 
x2ryder

x2ryder

Location
Moline, IL
Yes I took the carbs apart. They are brand new powerbombs. Everything was fine inside them. No matter what I turn the adjusters to it does not help. Remember this thing was running the other night. Then on the way back to the ramp it start acting up.
 
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x2ryder

x2ryder

Location
Moline, IL
Ok got it. I went 2 1/2 on the low speed adjuster and 1 1/2 on the high. I will take it out tomorrow and see how she runs. Thanks for all the help guys.
Cory
 
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mindless

mindless

X
Location
VA
I had the same problem when I was at Nationals.
Ran fairly well for a while,then it wouldn't run. It kept running like it was out of fuel. Replaced the fuel tank check valve, seemed to fix it for a minute, then it still did the same thing. Replaced the fuel filter, and bam, problem solved. Remember to check the little silly things too.
 
x2ryder

x2ryder

Location
Moline, IL
Tried the Riva jetting last night. The ski was super rich. Yet for some reason for the second time my damn cooling line into the manifold came off? After playing with the fuel screws I got it better. Then I broke my pump shoe bringing it back into shore! Oh I also added a new pcv valve.
 
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