73 240Z Choke Problem

[zman112233]

I'm not sure what's going on so I thought I'd come to the experts. My car has a hard time starting (especially when it's cold) and when I choke up the engine it seems to make no difference. Should it be noticable? While I'm trying to start it or even once I get the car up and going moving the choke cable does nothing. I've traced it back to the carbs and everything seems to be moving ok so the cables aren't broken. Thanks for your help!

[Arne]

Does your car still have the original flat-top carbs? Or has it been swapped to something different?

[240ZX]

When was the last time a tune-up was performed?

Tom

[zman112233]

I don't know much about carbs. I'll have to take a picture. The guy I bought it from had the carbs fixed up before I bought it.

[zman112233]

I looked in my Haynes manual and it looks like they are the stock carbs (There are two carbs with little black caps for putting oil in). (They don't have a butterfly). They have what looks like a piston that just moves up and down. When I pull the choke handle the cables move but the engine doesn't act any different and won't start any easier. What should I be looking for? When it's really cold my battery will usually die before I can get the car started.

[zman112233]

(I'm going to start by saying I know very little about engines) I think it sounds like my choke is not closing all the way. Can anyone confirm this, and if so, give me an idea of how to fix it

[Arne]

Before we can give any advice, we still need to know whether your carbs are the stock '73 versions, or the earlier '70-72 versions that lots of '73s have on them by now. Because the systems are very different.

Take a look at the pictures at ZTherapy to help you identify which type you have. The terms to look for are 'round-top' and 'flat-top'.

[zman112233]

Mine looks like a round top.

[zman112233]

I hate to bug everyone about this but I wanted to work on the problem this weekend so I was hoping someone might have some advice or ideas for me for the weekend. I really appreciate any help someone could lend. Thanks

[Arne]

If they are round-tops (with separate float bowls mounted on the sides of the carbs), the choke system is very simple. When you pull the lever, the fuel nozzle in the bottom of the carb should move downwards, which richens the mixture. So the first thing to test is to have someone move the choke lever while you watch the nozzles in the bottom of the carbs. Make sure that they move down when the choke lever is pulled, and also that they go back up when the lever is released.

For reference, the nozzle is just to the right of the vice-grips in the picture from ZTherapy linked below.

http://ztherapy.com/images/JapCarbPage_Pix/GasTubeDissassHelp.JPG

[Ed]

After the car has warmed up how does she perform? Does she start right away? How about after sitting for 30 minutes? When was the last time a tune-up was performed? Fuel filter, spark plugs, etc...??

[zman112233]

Once the car is up and going it runs excellent! I can even cut the car off and let it sit as long as I want... as long as the engine doesn't get too cold, and it will start right up.