Hi everyone. I just got a Datsun last week. Its a B310 ( square lights) . The car was running well until yesterday I cleaned up the carb and replaced the gaskets because they were leaky. Now, the car has problems idling. its kind of eratic. Running is good and theres no problems with the acceleration. I took the carb out a few times to re-clean the jets(I could not remove some jets as they seem stuck). I still cant seem to solve the idling problem.

I notice theres a kind of sound coming from the carb when its idling. It sounds like when your drinking trough a straw and the drink finishes. That kind of slurp sound. I looked down the barell and i can see there is fuel flowing in, but maybe its not consistant.

I read trought the tech section and checked the few things. The Dieseling valve works, and the fuel level is ok. Anyone have any ideas whats wrong. I have already taken the carb apart 4 times . Could a jet still be clogged or is there a vacuum leak. The carb is a stock carb. ( Hitachi DCH306 i think)

Thanks.

I'd go with a vacuum leak - dont ask me how to fix it i just no how to diagnose

Damn i hate that prob. I took mine apart an bam idle is every where never did fix it.

check the hoses coming out of the carby - maybe a blown inlet manifold gasket or carburater base gasket, if youve had the carby off maybe youve disturbed one of the gaskets - look in the vacuum advance line on the distributer - try and find out where the leak is coming from that would help.

Thanks for the info guys. Ill try searching for vacuum leaks.

The carb base gasket was a fiber piece which has hardened and cracked. The parts guy asked me to use the thick paper gaskets. I cut out one. Do you think thats still leaking. Should i use 2 ?

I think I need to go through all the cavuum lines again. There might be an 'unseen' leak.

Thanks :)

theres a thick agsket sort of thing under the carby between the carbie and manifold, have you replaced that? i had idling problems too and air fuel mixture wasnt changing much when tuning it. dad thought it was the jets that needed cleaning but when we inspected it that gasket (it has a different name cant think of it) had a crack in it. $14 from nissan and problem solved.

oh ok. I think its a 'fiber gasket'. i could not locate it here. So i made one out of thick paper. That could be the problem. Maybe I have to source a new one.

yeah that sounds right, were are you located? my local nissan dealer had to order mine in over night.

Im from Malaysia. Ill look around more :)

You can check vacuum leaks by spraying a little carb cleaner over the suspected area while the engine is running and if rev speed changes then it means you have a leak, and i agree with the idea of using the new gaskets i also tried to make my own gaskets and it brought me a lot of trouble. good luck.