What weber idle jets are y'all running with the 18rc?

Discussion in 'Engine/Drivetrain' started by northoak, Jan 3, 2022.

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  1. northoak

    northoak Newbie

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    Hey y'all, anyone know what size idle jets they are running? I've got an 18rc chinook (hilux) with a weber 32/36. My primary Idle jet is a 45, secondary is a 50. My mixture screw has to go out about 4 turns in order to stay running. Obviously way too much so I'm thinking I need to up that primary idle jet. What size jets are ya''all running?
     
  2. jetas

    jetas Grand Toyotaholic

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    Have you turned the idle speed screw in?
     
  3. northoak

    northoak Newbie

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    A bit but I haven't played with it too much since I'm trying to set it based of off this doccument:

    http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm

    in that guide Weber suggests that your engine should be able to run at their baseline settings and that if you have to turn the mixture screw out past 2 1/2 turns with the idle speed screw at 1 1/2 turns you need a bigger jet. I imagine I could get it tuned to stay running with the current jets but would rather get it tuned via their specs.
     
  4. jetas

    jetas Grand Toyotaholic

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    Does it have enough fuel? And is your choke actually working? Mine wont run or run like shit when cold if the choke aint set
     
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  5. sirdeuce

    sirdeuce Enthusiast

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    Carb jetting depends on the engine build. What jets are used in other engines is irrelevant. You might consider disassemling the carb and cleaning it before playing with the jetting. Even a bran new, out of box carb can have some blockage in the porting. Check all the jets as well for clean and blockage free orifaces. Loose jets, cross threaded jets can cause issues as well. As for the idle screw needing 4 turns out? Check the needle seating area and needle. So many things to check before you go messing with the carb tune. Start changing things and you can really get lost.
    As for jetas' comment on using the choke brings a question up. Is your engine warmed up when you have the issues? If it's cold definately check your choke setting and operation. Any and all tuning needs to be done at operating temps. Make sure your engine is warmed up before you do any changes.
    Other issues rhat can be suspect are your cam tining and ignition timing. Improper point dwell can have you chase your tail.
    Learn to read your plugs.

    Just my 2/100ths monetary units.

    Man, haven't had a carbied engine for 20 years, and ponts?
     
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  6. northoak

    northoak Newbie

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    I did confirm the choke is working and have a pressure regulator on there, it’s definitely getting fuel and runs well on the road highway etc just not at idle unless the mix is way out. I did order a 50 size jet to see if it helps out, should be here soon. Also played with timing a bit with no real results. Any idea where your timing is at? Mine is pretty advanced
     
  7. northoak

    northoak Newbie

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    All great points, no pun intended. Previous owner did an electronic ignition upgrade luckily. Timing is way beyond the stock 8 degrees but from what I’ve read these carbs like the timing quite advanced.

    As far as jets I figure maybe I could get the ballpark of settings if someone is running a similar set up with luck but you are right there’s no easy way out! My other rig has a 22r and there is so much more info out there, I’m new to this 18r world

    As far as something being blocked I actually just rebuilt the carb but it needed 4 turns before the rebuild as well. Eventually it sprung a leak at the carb to base so I figured I’d clean and rebuild it while I had it off.

    I ordered a bigger primary idle jet since they are cheap and will report back. Hopefully I’m not just throwing parts at it
     
  8. northoak

    northoak Newbie

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    Ps if anyone is running a Weber with an 18rc what’s ur timing like?
     
  9. sirdeuce

    sirdeuce Enthusiast

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    How far beyond the stock timing is it? Could be a sign of improper cam timing and/or a slipped harmonic balancer. Put #1 cylinder at TDC and check your timing marks. Do the same with the camshaft.
     
  10. northoak

    northoak Newbie

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    I did roughly confirm cylinder 1 tdc when adjusting the valves by checking gently with a screwdriver. Not sure exactly how beyond but I'd say more like 20 than 8. The previous owner also upgraded the points to a pertonix electronic ignition. Does that effect timing at all?

    Jet wise I went up from a 45 to a 50 on my primary Idle jet and have gotten closer to the specs recommended by weber but still about 3 1/2 turns out. bet than the 4 I was at but may need to upjet more.

    Now my temp light is always on even with a new coolant sensor and one of my turn signals doesn't work lol
     
  11. sirdeuce

    sirdeuce Enthusiast

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    I'd say to check the cam timing. I've come across that before, where the timing needs to be way off to run. The Pertronix wouldn't cause that problem. My last 18R had the cam off by 1 tooth retarded when I got it. It needed a bunch of timing and the power came on way too late.
    So with that, how does it run? All bottom end grunt or all top end power? What is your idle vacuum? Cam being off will have low vacuum. What town are you in? Might be someone close that has experience that may be able to lend a hand.
     
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  12. northoak

    northoak Newbie

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    These are great ideas, I confess I'm unsure how to check cam timing beyond confirming that the camshaft knock pin is facing up when at tdc according to the mark on the flywheel. When you say measure vacuum do you mean from the carb going to the vacuum advance? If so I'll measure the vacuum coming off my weber to the advance at iwarm idle and report back.

    I'm in North Oakland, CA. If anyone is nearby another set of eyes would be much appreciated.
     
  13. sirdeuce

    sirdeuce Enthusiast

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    Nothing to do with the carb or distributor, just the cam and crank.
     
  14. northoak

    northoak Newbie

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    Well for now I've been able to get my timing a little closer to stock by retarding it till it struggles, turning up my idle, and then repeating this process. My speed screw is in more turns than weber recommends and my mixtures screw is out (richer) more than they suggest but I plan on trying to upjet again. I'm running a 50 primary jet right now with no cat/ or egr. Thinking I'll try a 55 next.

    I'm hoping a bigger primary idle jet will give me enough fuel to sustain a decent idle speed at a timing that is less advanced. Not a perfect solution but I was worried about running it with so much advance.

    I ordered a couple manuals that will hopefully tell me how to check cam timing, thanks for all the help!
     

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