DATSUN 200B reving problem

[spoolintanabe]

i just got some 1.5inch twin su carbys fitted to the L20b motor in it.

it doesn't rev right, it idles fine, but just chugs, and revs all retarded when u give it a moderate rev., its got a big flat spot in it

its all hooked up correctly thats not the issue,
its a fuel issue. its chugs when u drive. and plus theres a loud sucking sound coming from the petrol cap now, i got 1/3 tank of fuel in there.

its being starved of fuel. and can't handle two carbys. what sorta fuel pump should i use to got good flow and lots of pressure. what about another cars factory pump? like something off a 6 cyl?

some help would be great.

plzzzzz

[spoolintanabe]

anyone?..
got any ideas

[M.J.H]

Well this is a Toyota forum but anyways.

The std fuel pump should be more than enough to feed the carbs.
Are the carbs fitted right, No air leaks or anything?
Have you unscrewed the plungers on top of the carbs and checked if they have any oil in them? Are the bells clean enough to move up and down freely?
If you leave the fuel cap off then does it want to run okay or not?

Also check the lines on the bottom of the carbs aren't cracked as this can cause the same sort of problems you describe.

Good luck and let us know how you get on with it all.

[leso]

check that you have replaced the plug leads in the right order....take your dissy cap off and see which way the rotor turns and go from there...

[gianttomato]

Make sure there is oil in the plungers - auto trans oil or Singer's sewing oil. Make sure the bells move up and down freely. Make sure there is a spring inside the bell. Make sure the jets are at the same height. Make sure the float levels are adjusted and make sure the needle and seat are clean. Also make sure that there isn't more than about 6 psi fuel pressure - needle and seat won't like any more than that.

The fuel pump that is there is more than adequate to supply fuel to your SUs.

[spoolintanabe]

hey fella's, thanks for the advice

i just started it again to move it outta the way for something.

it starts on all 4 cyl's there firing, nothing wrong there,

it was was running fine before hand with a single barrel factory carby, although it was only running on the 1st throttle,as the secondary had seiged, i was quoted about $400 to recon and get running.

i bought the twin su's for 100 and the mechanic charged me $110 to fit them and get it running. so it sorta cheaper ay.

i checked the oil in the plungers, theres hardly any in them. do these lube the working parts. it runs on idle, but when u give it gas it bogs down.. it this due to the parts nothing being able to move freely, because there lacking lube?. so they dont spin freely and make it run like shit , right? they have to run smoothly to work ay.

. note, before hand with the previous packed in carby, it was surging, like fuel surge, thats why i said the fuel pump.

[TA-022]

i have a similar issue right now and its a case of too much fuel.

[allencr]

Lift the piston with you finger, and let it drop. There should be a 'thud'.
They don't spin, but have to be able to freely slide up & down.
If not, it is either dirty or the jet & needle are binding and it needs centering.
The oil provides resistence with the little valve on the end of the plunger.
Try lifting the piston with & without the plunger screwed down and you'll see & feel the difference. It's way of coping without an accelerator pump.

[vtrfirestorm]

"It just chugs and the ther is a loud sucking sound"

its a datsun - they all chug and they all suck - that is normal

Just trying to help

Fuel pump size is not the issue. You have not connected the vapor line up incorrectly have you?

cheers peter

[Hurricane]

does it back fire and that when you are trying to acc??? might have to go get the carby looked at, but go back to the basics, cheack the plugs, leads, dizzy cap and points, timings, air leaks, mabye a vac hose is off some were, has happened to me a lot can say i know alot about the SU so can really sugest any thing oh maybe see if the slide is slideing ok? it might not have any fluid in it and it may be doing up to fast, and to much fuel might be goin in? i know that happened on my CD 175 caarby on my turbo 3T.

[spoolintanabe]

thanks again for the advice.

i got a mechanic buddy coming to look at it tomorrow.

it seems to idle really well. but when u give any gas, it goes all limb and dead and putts and carries on.

i know they chug and suck loud. but i know there not good chugs and sucks.
it chugs after a huge flat spot, and probably just needs to be tuned right, it has no power, and is acting like a mower on 1/4 choke.

[TA-022]

well mines fixed!

turns out it was a jet? inside wasnt screwed into place. So instead of
it spraying fuel it poured in.

[spoolintanabe]

anyone know where i can get this sewing machine oil from... or is auto trans fluid better, or either?

[mtp_69_i]

anyone know where i can get this sewing machine oil from... or is auto trans fluid better, or either?

spotlight should have it

[spoolintanabe]

what about air tool oil, does the job?