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Wed Jul 15, 2015 12:06 pm

I purchased a Single Dellordo 36 used that needed rebuilt. No big deal i thought so i got a kit over at aircooled.net and then tore it down and gave it a good bath in carb soak and then blew out everything and dryed it real good. I then proceeded to install all the new parts in all the places i removed the old ones and then started her up. She needed a little adjusting but it idled good not smooth but pretty good i then took it for a ride and it runs ok but spitts and sputters on acceleration so i tried adjusting the accelerator pump squirt and that didnt help and then once it warms up (oil temp around 165-185) she starts gradually missing and sputtering on acceleration up around 1800-3500rpm range. I have a modified heated intake done so icing is definitely not an issue. I started the air mixture screw at 3 turns out then adjusted it in until it started to die down then went back out almost 4 turns it ran the best. I don’t have a syncrometer to set the bypass screw so i adjusted them at 1.25 turns out on both. I swapped out dizzys from my electronic to points and no change, replaced plugs with Bosch ( drove it and checked and it looks like they are lean), plug wires, timing adjusted, valves at .006 (all of them), no vacuum leaks.

I have a bone stock 1600 motor with 110 compression WOT engine cold.
I am running a single Dellerto 36 with a pair of 28 venture,
main jet stack has tall air corrector jet of 180, Emulsion tube 9164.1, Main gas jet of 125.
Idle gas jet 55.
accelerator pump jet 55.
I do not have velocity stacks installed.

All i can find is talk about dual setups of this so i don’t know what i really should have in this to run right and i don’t want to just throw jets at it. HELP me before i rip this air cooled out and install a water cooled.

Is my compression too low? first crank i can see the gauge and it hits about 25psi then gradually up about 5-8 psi untill it hits 110psi.

Wed Jul 15, 2015 12:32 pm

spit and sputter like a miss??.. or just a big hesitation?
do you have a pic of the manifold you are using?

Wed Jul 15, 2015 1:07 pm

I did a little screwing around just now and took the 55 idle out and put in a 60 and replaced my main 125 with a 140 and the hesitationa and stutter went away but i still have a miss on acceleration once its warm. then i came home and took an old set of small mains i had and drilled them out to 157 and its got more pull off the line now but the miss is still there. the miss is what feels like a lean miss if i go slowlly into the throttle i can controll the miss bit it gets gradually worse the longer i drive it untill it doesnt matter how i step on the gas

Wed Jul 15, 2015 4:49 pm

You've proved it's not a jetting problem, which is good. Might actually believe me.

Change the intake to have 1 3/8 tubes instead of 1 1/2

A stock engine does not need larger size tubes. You can just glue and stick them inside, don't actually have to work very hard. To be fancy use 1 1/4" ID copper.
How'd you get the larger tubes inside the end castings?

Wed Jul 15, 2015 9:13 pm

those are stock tubes un modified so im guessing I have the 1 3/8 tubes on the upper manifold already but I can measure with a caliper when I get home from work. I keep leaning to compression issue because as soon as the engine temp cools a little she runs strong again and no missing. its not a miss that I can pinpoint to any one cyl either because at idle she runs good only under load it misses.

Thu Jul 16, 2015 4:36 pm

Yep, as I suspected.
You think I'm full of baloney.

I don't mind. 70% of the guys whining about how their single carb doesn't work give up before learning if I'm right or not.
So, not a lot of data is gained about induction systems, it does prove people don't know jack about how to make these things work. So, at least we are learning something!

Fri Jul 17, 2015 1:45 am

i measured my tubes tonight and i do have 1 1/2 outer diamater tube. so i should put the copper inside on the straight runs of the intake? i understand the theory of reducing the inner diamater just like the ventury in the carb.

Fri Jul 17, 2015 1:59 am

Yes!
I like to explain it as: it cannot flow more than the venturi.....so the manifold must match the venturi size. venturi 86% of runner ID is a good ratio.