1987 daihatsu s81p. Adjusted new carb with manual choke till I'm blue in the face. Bought it with this carb not sure what's going on. New plugs wires and cap and rotor timing good. New water pump and timing belt. Still dead spot right off idle which is aggravating as hell when you try to go slow. Any ideas would be great. Also I am a new owner of a mini truck and love it. If I zip tie the choke butter fly closed about 80% it runs fine?
You’re either a little rich or lean. The fact that tying the choke back helps says your going rich. Does the carb have an accelerator pump?
yes i think it is on the bottom of carb cant adjust it unless you pull the carb off. The adjustment linkage is to far down in motor.
Have you adjusted the best lean idle? With the ruck al the way warmed up, you set the idle speed as low as you can get it. Then turn the mixture screw in an 1/8th of a turn. If the engine speeds up, reset the idle as low as you can, and try turning it in another 1/8th. Keep doing it until the idle mixture is as low as you can get it.
Jigs is correct, and spot on! I went through the same thing, and after several, adj. I finally got it right! For me it took a lot of time tweaking back and forth, but you really will learn your vehicle, and what it likes and doesn't like! Providing everything is working properly, and newer like your saying, don't assume any thing. I actually made a few custom bends, in my linkage, to get mine right, but that was after several hrs. of confirming what was needed! I don't recommend bending your linkage right off the bat! I still have to feather my manual choke upon starting, just like the old days before auto chokes were the norm. Then once she warms up were golden! Good Luck! Limestone
I was amazed when I first got my S80 and found in the manual that the initial setting for the idle mixture screw was to back it out 4 1/2 turns, then adjust it til it idles at 950 r.p.m.'s +/- 50 R.P.M.'s. In all the old carbureted engines I had worked on you backed it out 1 1/2 to 1 3/4 turns and went from there.
That's what can be a little confusing with these things. Some of the old school traditional things that we learned on the American cars, somehow, kinda don't apply here! But through experience and sticktoitiveness, we seem to finally conquer, these things!
All those things plus a coating of blood and a whole lot of language exercise usually teaches us something.
I would add to check your vacuum lines, they may not be where they are suppose to be if you have the aftermarket carb. I had to re-route/remove some of them to get the engine out of the dead spot that you speak of.
The best I can say is, here is the vacuum line diagrams I have found. I studied them and stared at my engine for a few days and played around with lines to get the best running idle.
Limestone, I would like to see your manual choke setup. Mine is a kluge, and I never could get the right cable or connection to work properly, so I still have to turn around in the driver seat and literally adjust it manually. Thankfully, I have the Jumbo Cab and there's a large porthole behind the seat from which I can see the carb pretty easily. I put my choke lever in the center console near the handbrake, but it hardly ever works.
See if this helps! Same pic, just two diff. views! Maybe take a pic with your I phone and blow it up! Limestone
So, to explain, my situation. Left Hand drive, right hand on key when starting, for me it's most convenient, with my left hand free, I installed the choke knob, under, and behind my left knee, so I can feather it on start! Works great! At the carb., you can pretty much do what you want, to bend it around, and install it the way you need to! Not that difficult! IO installed it the least evasive for me, as to work this way for a long time, free of travel, and problems, down the road! Limestone
