Ok so freshly rebuilt L20B with recon w53 head (small port) standard everything else except weber 32/36 dgv carb. 20 thou overbore as well.

It starts and runs, drives, but wont start without the choke being on and it wont idle period. the idle screw is all the way in and it still doesn't idle, just splutters and stalls.

What would you guys think, havn't had time to really look at it, this is just a quick post, going out tonight so can't really look at it until tomorrow. I'll give more details tonight.

Thanks.

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project

Ok so i finally had time to look at it today. Pulled the top off the carb, cleaned the jets etc and everything seemed fine. But i decided to pull off the carby just to have a closer look and in disbelief when i removed the carby i found half of the bottom gasket missing! (the gasket between the manifold and adapter plate).

The engine had sucked half the new gasket through the engine and burnt it! Im a bit worrried as to what its done to my engine??? what do you guys think?

Anyway put it all back and tightened it up hard with gasket sealant and now it actually runs quite well. It idles and revs pretty smooth.

But it does have a flat spot around 1500-2000rpm and its running really rich.

So if anyone knows could they tell me how to get rid of the flat spot and which screws are my fuel/air mixture ones?

Also where can i connect my distributor vacuum advance line too?

cheers guys.

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project

these should be a port on the side of the carb to put the vaccum line to .LOOK!!! where the idle mixture tension spring screw is.

Also on the second barrel behind the carb make sure your spring is on there kkeping the second barrel closed untill the mech linkage opens it up.
If not spring the butterfly will open too soon causing a vaccum loss.

time the motor again and adjust the mixture screw. Turn it in untill it runs rough then turn it out then pick the middle setting.

shouldnt do toomuch to then engine. my dads kombi used to suck in the jets thorugh the engine, and it never stopped for 20 years.

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- 1972 Datsun 1600 S15 SR20DET

Ok so i connected the vacuum advance line and thats ok, but i still can't get the mixture right. The idle mixture screw is wound all the way in and its still running very very rich.

What do the two screws just under the choke flaps do? are they the mixture screws for mid-high range rpm?

I've got new plugs, new points, new dizzy cap, new rotor and reasonably new eagle 8mm leads. Timing is at 16 degrees btdc.

Anymore help on this will be much appreciated.

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project

turn the mixture screw in/out untill it smoothens out
then back side of carb there will be a idle speed screw to adjust rpm after the car is warmed up. You will see it opens up the butterfly.

also make sure on the second barrel the spring is keeping the second barrel closed(if not there will be a vaccum loss)

adjust the timming to maybe 12BTDC or maybe less
adjust this all again
since you have points ck the point gap and dwell(use a meter) This will change it also.

make sure dist is not worn with a worn out bushing causing the points to open up on there own(shft wiggle)

make sure cap is grounded

8mmm leads means the isulation thickness right? so it dont jump spark

BAZ at Datsport will handle this

Hey there, i've fiddled around with the idle mixture screw so much and it doesn't change a thing what so ever. The mixture just stays rich.

And the oddest thing happened to me the other day. It was a really really hot day and i started the engine to see if i could do some more tuning and then switched it off for about 20 mins and then i went to restart it and it was running like a lawn mower again.

Could this be the heat affecting the dizzy?

Daniel.

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project

it can only be the carby - the base plate might be warped casing the gasket to not seal properly - causing a vacuum leak (no idle).

or your floats might not be adjusted correctly - check them too.

by the sounds of it you should just get a new 32/36 and have it jetted and tuned for your engine at present. it sounds like it's well and truly rooted.

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frankenstein projects R us.

The Republic of Western Australia -
Propping up the Nation's Economy since 1901.

I dont really want to replace the carby itself. Is there anyone in SA that i could take it to, to have it professionally rebuilt, jetted and tuned?

The adapter plate is new.

Daniel.

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project

nah not the adaptor plate is warped - the base plate IN THE CARBY is warped. was a prob with i think Team_dat's carby.

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frankenstein projects R us.

The Republic of Western Australia -
Propping up the Nation's Economy since 1901.

Oh i know what you mean. Yeah it doesn't look all that flat. But the strange thing is i got it to run, idle and go real well for a few days except it was running really rich and had a flat spot and then all of a sudden the engine starts running like a lawnmower again.

Thats what i can't figure out.

Daniel.

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project

Oh i know what you mean. Yeah it doesn't look all that flat. But the strange thing is i got it to run, idle and go real well for a few days except it was running really rich and had a flat spot and then all of a sudden the engine starts running like a lawnmower again.

Thats what i can't figure out.

Daniel.

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project

maybe you have fuel pump issues? is the pressure too high?

fukc i hate diagnosing stuff over the internet!

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frankenstein projects R us.

The Republic of Western Australia -
Propping up the Nation's Economy since 1901.

How would i know if the pressure was too high?

Its the same mech. pump i used in the same car with a different 2L engine with stock carby and it ran fine apart from the exhaust valve being stuck open on cyl no 2. Lol.

But how would i rectify/eliminate the fuel pump as being an issue.

Also how to i make sure my floats are at the right level and how do i adjust them?

Daniel.

You've all been great help so far!

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89' R31 Skyline Ti, 5 speed - Daily
89' R31 Skyline Executive - Slider/track whore
8' Stanza SSS - Rally Project