dies when past quarter throttle

[myblackz28]

i just bought a 1990 superjet and it runs awesome at idle, part throttle but once i go past quarter throttle it bogs down and dies. if i let it idle then suddenly punch it, it takes of, then dies and shuts off. then i try to start it and it takes a few seconds. definately seems its not getting gas. im leaning towards the fuel filler? any thoughts? thanks

 

[Tyler Zane]

i would check the fuel filter and all the lines first being its easy, then then check carbs. more than likely a carb kit would help considering year anyways.

 

[Waternut]

Since you just bought it, you have no way of truly knowing if your jetting is correct or not. Start with a pressure check (not a compression check) on the engine to determine if there are any air leaks. Do a search on leak down tests or pressure check for more details on how to do that. Fuel filters are cheap and you can pick one up at walmart for like $3 to eliminate that possibility. I'm guessing the carb needs to be rebuilt but do the other two things first before spending the money on that.

 

[myblackz28]

i should have put in there i checked all the fuel lines, has a new carb and new filter as of last year (the guy claimed). and i removed the intake filter and the carburator looks spotless. found some schematics online on some of the hoses and a lot of them were cobbled up. not connected to the right spots. hopefully nothing is messed up. just need to know what to do with the hose connection that would normally go from the head to the factory exhaust. the real tiny one towards the front of the head. seems how i have a coffman exhaust there isnt a place to connect that line. do i block if off or what? thanks

 

[myblackz28]

just have a quick question so i can go try it out. with factory exhaust there is a small port that goes from the head to the stock exhaust, its prolly a 1/8 inch inside diameter. my ski came with a coffman exhaust and the guy had that port hooked to the gas tank vent hose that goes into the handle stem. i got all the hoses straightened out just not this one out of the head. anybody know do i block that off or does it need to be connected to something?

 

[SUPERTUNE]

Stock head 1/8 water nipple fitting gets blocked off (cap with a vacuum cap and zip tie) with any aftermarket exhaust system, the stock pipe is the only reason that you would use it.
On the fuel issue, pull off the carb and pull off the fuel pump plate and check to see if the internal barrel fuel filter is clogged up...

 

[myblackz28]

ok thank you, and if the fuel tubes going into the carb didnt fix it i will give that a shot on the beach

 

[ATS_Aaron]

Stock head 1/8 water nipple fitting gets blocked off (cap with a vacuum cap and zip tie) with any aftermarket exhaust system, the stock pipe is the only reason that you would use it.
On the fuel issue, pull off the carb and pull off the fuel pump plate and check to see if the internal barrel fuel filter is clogged up...

And pull the diaphragm cover and see if the needle and seat are stuck. If I remember what you bought it's a single carb ski so the carb should come off in like 60 seconds.

Aaron