Help with power jets

extremedesigndave · Dec 23, 2009

Ran my sled in the pasture today, it seams no fuel was going through the power jets, but it was not boosting up, I just want to make sure it will be ok!!!

I might of got it up to about 45mph before i had to let off but i did not see any boost, my waste gate might of been open and my blow off might of been open,

Here is the question

I put one powerjet each (the non adjustable mkuni style with a jet in the tube) on the inlet side of the carbs with the fuel tied into the bottom of the bowl and one more non adjustable mkuni in the charge tube but with a needle valve in the supply line to adjust the flow that the fuel line is y'ed into one of the carb PJ's supply. My EGT never got above 1000 and i might of been at about 6k rpm with my bowl pressure set at 4-5psi.

DOES THIS SOUND RIGHT? I just want to make sure when I take it up in the powder to test it and play with it my PJ's will be getting fuel into the system!!

Please let me know,, I have spent so much time on this thing and dont want a melt down

devilrmk · Dec 23, 2009

That sounds fine Dave.

Are you sure it wasn't boosting because it was too rich? If I have my powerjets turned out a couple turns it won't boost, just blubbers.

You can really tell when the powerjets hit on mine when they are too rich. It will run clean until just a point in the throttle then it just starts blubbering all the sudden.

How far down the venturi does your tube sit?

extremedesigndave · Dec 23, 2009

DUDE, if you still have my number can you give me a call?

extremedesigndave · Dec 23, 2009

Check Valves

Do all power jets have check valves? These dont, but if the fuel pressure is higher you should not need them right>

devilrmk · Dec 23, 2009

Yea I will call.

No, I don't think any powerjets have check valves. Mine don't.

You have them sourced to the float bowl right? And installed into the throat of the carb?

If the tube is in the airstream they suction.
Doesn't matter what your fuel pressure is, because that pressure isn't in the carb bowl. Its only in the fuel lines up to the floats.

As long as you have your carb bowl vents referenced to boost there should be no issue with them.

zrt1 · Dec 23, 2009

you also have to remember that on your third powerjet that it is tee'd to both carbs. When it comes on boost and that jet goes to one float bowl the other two will not come on at the same. both float levels will not be the same.

zrt1 · Dec 23, 2009

and yes they do make a check valve for some. the third pjet on mine is in the charge tube and it has a check valve to keep fuel closer to the jet. Other wise it has about a 10 to 12 inch draw befor it comes on.

extremedesigndave · Dec 24, 2009

Leaned it out and is spooled right up,

The other thing I noticed was that my y is above the fuel float level so I am going to change it so it is below the fuel level!

What if I tied the third into both bowls? would it work? Just so it is taking it from both instead of one?

I don't know, All I know is it spooled up and i was right around 1200 with a brownish plug,

zrt1 · Dec 24, 2009

yes the third needs to be teed to both bowls, when your on boost if you dont your pulling alot of fuel from one float bowl. ive have a super small brass tee for 1/8 fuel line if you need it.

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Help with power jets

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