Author Topic: Power piston Step up springs for Monojet  (Read 1733 times)

Jase

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Power piston Step up springs for Monojet
« on: September 19, 2018, 01:49:11 PM »

I am making my first attempt at tuning a Carb, & my first attempt is on a '74 Monojet sourced from the junk yard. Do quadrajet power piston springs work on the mono jet?

(I am getting fuel out of the main jet-booster at a fast idle, as well as  a stumble when accelerating under a load... (or shifting the non-synchro transmission) 



Offline Cliff Ruggles

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Re: Power piston Step up springs for Monojet
« Reply #1 on: September 20, 2018, 02:29:20 AM »
It's been too long since I was into one of those so don't know.....

Offline Sonny

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Re: Power piston Step up springs for Monojet
« Reply #2 on: September 20, 2018, 06:15:25 AM »
For what it is worth the Internet retailers selling Rochester power piston spring assortments list the same kit for both Monojet and Quadrajet.

This is an observation not a fact.  ;D

Jase

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Re: Power piston Step up springs for Monojet
« Reply #3 on: September 20, 2018, 07:10:45 AM »
Thank You Cliff,  Thanks Sonny. I will get one from Cliff, and see what happens. Nothing to loose by trying, and getting some education on the subject.
Jase

Offline A.G.V.chevyfreak

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Re: Power piston Step up springs for Monojet
« Reply #4 on: September 23, 2018, 12:57:36 PM »
Hi. 3 of my cars runs on the monojet. Here in south africa it was the main carb used on inlin chevy 4 and 6 cyl.
the piston and needle gets lifted via a link from throttle shaft.
The spring is only there to make it go rich if the link hooks out , usually happens if heavily worn or if someone tries to bend it more in a effort to lean it out.  Pics attached.
So any spring wil basically work.
if its dripping fuel from the booster at idle then the blade is adjusted too high. And running of the main system.
The stumble comes from accelator system.  Pump worn or passage clogged or checkvalve sticking.


« Last Edit: September 23, 2018, 01:04:07 PM by A.G.V.chevyfreak »

Jase

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Re: Power piston Step up springs for Monojet
« Reply #5 on: September 23, 2018, 07:17:06 PM »

the piston and needle gets lifted via a link from throttle shaft.
The spring is only there to make it go rich if the link hooks out , usually happens if heavily worn or if someone tries to bend it more in a effort to lean it out.
So any spring wil basically work.
if its dripping fuel from the booster at idle then the blade is adjusted too high. And running of the main system.
The stumble comes from accelator system.  Pump worn or passage clogged or checkvalve sticking.

Thanks this is helpful. I have started to wonder if too high a float adjustment will also cause the main system to come into play two early... I will look into a new link like what you posted.. then play around with bending it (if I have a replacement)

Offline A.G.V.chevyfreak

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Re: Power piston Step up springs for Monojet
« Reply #6 on: September 24, 2018, 07:29:52 AM »
Pleasure.
Once you strip and inspect its a simple carb in design and function.