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Making a Q-jet handle angles better

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Triaged, Apr 3, 2001.

  1. Triaged

    Triaged 1/2 ton status

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    I need some advice on mods (other than FI) that will make the carb run better at angles. I have a 400 SBC in my '71. I don't know what year the carb is. When I go up steep hills when wheelin' it starts to cut out. Just like I let my foot off the gas quick than back on again and again. I have herd that the Q-jet is the best carb at angles so what's up? Also is it possible to put a electric choke on an older carb? Right now it is just tied open (not to cold in SoCal).

    '71 Blazer CST with alot of rust
     
  2. Blazer79

    Blazer79 1/2 ton status

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    I think maybe getting a different shape of float? I don't know how do they classify them, but my Doug Roe's book on Rochester carbs shows several floats. Maybe you could ask a shop which models they carry.

    I believe it is possible to convert the carb to electric choke. When I was about to buy my new Edelbrock Q-jet, I emailed Edelbrock and they gave me the name of a company that has a conversion kit. Give them a call, I'm sure they'll help you. I ended up not converting mine because the divorced style choke in mine worked perfectly.

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  3. Blazer79

    Blazer79 1/2 ton status

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    Also, make sure there's a plastic cover on the fuel bowl, just on top of the float. It's very easy to forget it when you re-assemble the q-jet, and a previous owner or mechanic could have said "the heck with it" because you have to disassemble and reassemble the carb just to put it back inside.

    This plastic cover prevents fuel splash that may be giving you a hard time on weird angles.

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  4. Wheels

    Wheels 1/2 ton status

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    On angles and Q-jets. They are the best carbs for handling angles, however they have their limitations. You may be at the angle limit of the carb. Do what Blazer 79 advises, and if it still won't work, check the angle that you are trying to operate at.
     
  5. Burt4x4

    Burt4x4 3/4 ton status

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    One more trick is to put a 3" piece of fule line on the float bowl vent tube to extend it up into your air cleaner. This will prevent fuel from sloshing out thru the vent tube into your primariys. Other than the things mentiond you can adjust your float higher, but if you do you must have the two pieces mentioned inplace or....splish splash your carb is takin a gas bath....

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
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  6. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    It's been my experiance that the EVAP Quads (77 or newer) tend to have this problem less often. Those have closed vents that port out the front. you will need to use a newer breather off a truck equiped with AIR pump and you can use the AIR pickup tube in the air cleaner and use it for the vent. I'm having the same problem on my 75. I will be using a carb off a 79 be cause my 79 has never had this problem. I'm using a 85 air cleaner to make it all work and the 79 carb is a heat riser (has bowl with a pipe routed through the intake exhaust cross over) style that can easily be converted to electric choke.
    Another point to watch for is the fuel will dump out the holes that the secondary meetering rods pass through draining the float bowl straight into the secondaries. Seem to recall they put a lip to slow this down on the newer versions also.

    Diging it in the dirt with my K5's
    Grim-Reaper
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  7. Burt4x4

    Burt4x4 3/4 ton status

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    I hear what your sayin Grim, BUT I just wanted to say that my carb, Edelbrock 1901 Q-Jet, Does not do this on rutine angles and hill climbs. Yes that time I put my K5 on two wheels(pass side) in a sand bowl last year the motor did die but once I got it back on all 4s it fired right up even though I was still at a very steep angle. The Edelbrock version of the Q-Jet way out performes my old Rochester Q-Jet, WAY better!!!
    .02c

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
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  8. dyeager535

    dyeager535 1 ton status Premium Member

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    If I remember the new Edelbrock, it is a clone of the '75(or so) and up "emissions" style Q-jet..not the "pre -emissions" style.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
     
  9. Burt4x4

    Burt4x4 3/4 ton status

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    Hmm duno for sure about that??? But the 1901 part# is for the early Q-jet 66-73 applications and the 1902 is 74-79 or something like that anyway..... I guess an email to Edelbrock would answer that question...mabie[​IMG]


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  10. dyeager535

    dyeager535 1 ton status Premium Member

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    Just look at one...if it has a "flat" front, it is not emissions style. If it is more "odd" (not flat hehe) shaped on the front, its emissions. Also look for the "dome" on the passenger side, front, top of the carb for the aneroid cavity, which also is an "emissions" style carb feature. Yep...1901 IS a pre-emissions style casting. Those are the 750cfm castings. All the rest (795 and 850) are "emissions" style.

    http://www.dorianyeager.com/index2.html
     
  11. Triaged

    Triaged 1/2 ton status

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    Thanks for all the quick responces. I'll make those mods over the weekend and tell you what happens if I get a chance to go wheeling.

    '71 Blazer CST with alot of rust
     
  12. Triaged

    Triaged 1/2 ton status

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    Thanks for all the help. I tried Burt4x4's idea about the 3" piece of fuel line on the float boal vent. It worked great. It did finally stall but that was because of running the pickup in the tank dry (had 3/8 of a thank and was at such an angle that the fuel gage read E). I'll also look into a 77- carb when it is time for a rebuild.

    '71 Blazer CST with alot of rust
     
  13. Blue85

    Blue85 Troll Premium Member

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    I have never had mine stall because of angles, even though I have been very afraid of rolling it in most directions before. The carb only has to be good at angles you can drive at. When you're rolling over, a running engine doesn't help too much. As the angles get steeper, eventually you will have to worry more about getting oil to the engine and gas to the fill line than you will with Q-Jet performance. Of course, you can run momentarily without oil or gas to the fill line and the carb still needs to operate.

    <font color=green>"MAN THOUGHT HURT BUT SLIGHTLY DEAD" --Providence (R.I.) Journal</font color=green>
     

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