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Mini Truck Aftermarket Carb Swap

Discussion in 'Mitsubishi Minicab' started by Jack3laynee, Aug 26, 2019.

  1. Jack3laynee

    Jack3laynee New Member

    Hello everyone, I need help with my carb. It idles perfect all day long, when you start to give it gas it goes for a few seconds and starts to choke out. Like it’s flooding out or running out of gas. Now here the kicker. If you pull the breather off and look at the front of the carb, you see the butterfly for the choke and above that you see some jets in an accumulation of three holes. Two little small holes on the upset sides and a bigger oblong hole in the middle. If I plug the two smaller holes, it runs like a scalded dog with no problems. I would leave it like this however when it goes back to idle it will start to flood out at idle. Pull the plugs out and it’ll idle all day long but will not rev and keep up. I’ve cleaned the carb twice. Float seems to be in a good working location but I’m at my wits end and really don’t want to fork out 500 bucks for another carb. I’ve taken pictures so everyone can see and am open to any suggestions. I need to get this thing right. Thanks for any help.

    This is without plugs...

    This is with plugs...
     
  2. Jack3laynee

    Jack3laynee New Member

    Forgot to mention, this is a 1993 Mitsubishi MiniCab.
     
  3. VanOne

    VanOne Member

    Checked the distributor to rule out it being a carb issue? Faulty distributor can cause issues when you press the pedal.
     
  4. David Ogden

    David Ogden Member

    Those holes are air passages into the low & high speed jet towers, what you are doing essentially is enrichening the mixture by stopping the air flow. Either the float is set too low or as VanOne said it has an ignition problem.
     
  5. Jack3laynee

    Jack3laynee New Member

    Thanks guys for the info. Will look into this topic of the ignition and will test what I can. Will also pull it down again and look at the float level. I figured by plugging these I would be “flooding” the carb hence needing more fuel I suppose. Will look at both of these Andrés what I can and report back this weekend. Thanks again.
     
  6. Jack3laynee

    Jack3laynee New Member

    Ok I know this is an old thread i made but I am just getting back around to my little truck. Have been in the process of other things and just havnt had the time. So I advanced the timing a tiny bit by the distributor and it ran a good bit better however i am still running out of fuel. I can ride all day long in 1,2,3 and 4th as long as i dont get on the gas to hard. Obviously this limits the speed down to about 35 maybe 40 if im lucky. Get on the gas too hard and it spudders. I have the carb out tonight and have raised the float level in the carb. Made some new gaskets for the carb and will reinstall tomorrow and will post an update of how it performs. However, i do believe my carb is in bad shape but not to the point of not repairable if i had the parts. The jets, the black plastic piece inside the bowl that houses the jets. If i could find another one of these with the jets that would be a huge plus. Mine looks destroyed from someone trying to do something to it im not quite sure. It was like this when i bought the truck and would greatly pay for this piece. I just dont want to fork out 400 for a rebuilt carb when i can rebuild by own. let me know. Thanks again. Im glad this forum exist. Id sure be lost without internet.
     
  7. Newlands

    Newlands New Member

    Might be worth checking your fuel filter as it bogs down when you floor the throttle.
     
  8. Jack3laynee

    Jack3laynee New Member

    Thought of this yesterday right before I took the carb back off, I did add a fuel filter and tried it but did not work. I also looked at the filter above the tank and it seems to be going to the vent or canister so I did not change it. I could blow through it so I figured it’d be fine. Thanks for the input tho for sure as I almost didn’t do that lol.
     
  9. Jack3laynee

    Jack3laynee New Member

    Ok so I've decided to change over to a CV-40 carburetor. I've fought with the OEM for years now and I've always known there was a problem with the jet holder in the oem but I've been trying to buy the correct parts and its a no go. Other than to buy a reman carb for 1200 bucks. Aint happenin. So i got an adapter off ebay, aluminum, and slapped a cv-40 motorcycle carb on, drilled the main jet, now in process of drilling the idle jet to see if it gets better but man i gotta tell ya, that was a 90% improvement and I bet I'll be able to work out the other 10%. Also am messing with the Vacuum timing advance. as for now I've advanced the timing by the dist. cap. This is a hard one if anyone has a suggestion. If they make an add on ported vacuum plate or something I'd be interested for sure. Anyway, I'm happy with the swap and will comment after I drive it a bit to get the feel.
     
    Newlands likes this.
  10. Newlands

    Newlands New Member

    Sounds interesting. Presumably your distributor has a vacuum advance and you just need a port from the inlet manifold??
    Can you not make a replacement for the black plastic jet holder in the original carb? I say this without having a clue what it looks like of course.
     
  11. Jack3laynee

    Jack3laynee New Member

    So i dont have a 3d printer but even if i did, i have no idea what the original actually looks like. If someone would take theres out and have a copy made or would allow me to make a copy i would. My plastic jet holder is all messed up from someone previously going into the carb before i bought the truck. With that said i did everything i knew to do with the oem carb. And just because its the OEM and made for the truck so to speak, i would still put effort into it if i thought i could make it better or exactly how it was from factory. The vacuum issue goes like this, i currently have it hooked up to the manifold vacuum. But its just not good enough. So, come to find out, there happens to be two kinds of vacuum, one which i am using called a manifold vacuum and the other called a ported vacuum. They work opposite of each other. Ive read into that the last few days and have tried to come up with a solution. Again if i could make a plate that would give me ported vacuum that would be a game changer for old cars. Thanks for the advice Newlands. Do you happen to have a 3d printer or a way to make that jet holder piece?
     
  12. Newlands

    Newlands New Member

    I’ve got a 3D printer. In fact I’ve got a machine shop, but as you say without the original to work from it would be tricky to make a decent replacement for your jet holder. Maybe there is a parts diagram on megazip.net ???
    And I’m in the U.K. but that’s not insurmountable. But if you think I can help in some way let me know.
     
  13. Jack3laynee

    Jack3laynee New Member

    Heck yeah that what I'm talkin bout. I've searched all over the web but i will keep searching. If and when I find them, I will def get in touch with you. I'm sure I'm not the only one who has needed this. However, my solution is getting better by the day. I added a K&N directly on the new carb of the mini. My truck has AC so I've been fighting the last few days to find a way to idle up the new CV carb when the compressor is running but i found a way tonight and will finish it up in the next few days as the parts come in. I took a weedeater shaft and melted it in half, also brazed the head of the idle screw to the shaft and brazed the ends to keep it from unraveling, drilled a small 1/4" hole right under the drivers seat and ran the shaft, or now idle speed cable through so i can adjust the idle as needed. It wont be automatic but it didnt cost me a hundred bucks either. Ill post some pictures in a few min if i can get them to upload. Ill def keep you in mind if i can find a good enough diagram. Thanks
     
    installater and Newlands like this.
  14. Jack3laynee

    Jack3laynee New Member

  15. VanOne

    VanOne Member

    Well, I have a 4WD 1987 3G81 engined Minicab which is going to go through a similar conversion, though I bought a ready made adapter kit that allows using the stock air box & everything. Hopefully won't be too much trouble..
     
  16. Clay1968

    Clay1968 New Member

    How did it go with the swap?
     

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