For some background I have a '71 Datsun 240z and have made a few modifications to it so far

- replace solenoid, new plug wires, new spark plugs, cleaned the carbs. 

it worked fine until the engine sat for awhile. I put on a new valve cover and a new exhaust. since then I can't get the thing to start. Now every time I try to start it it'll sound for about 2 seconds like its going off of starter fluid then cut out, totally unresponsive to the throttle. it'll only do this for the first go around and after that i can crank for days and nothing happens. This makes me think its a fuel/spark issue because its getting flooded so it only happens the first time, however, since this problem started happening i've tried the following.

- checked the fuel to the carbs. i took off the hose and cranked the engine and got a lot of fuel coming out

- i made sure that the plug wires corresponded correctly with TDC and that the firing order was all correct

- got a new battery

- got new spark plugs

- cranked it with a $^!# ton of start fluid. 

I havent adjusted the timing but i'm guessing it should be fine if it was fine before and I never took out the distributor. 

 

any suggestions would be greatly appreciated. 

Make sure the nozzles are moving freely. 2.5 turns down to start with. Don't get pissed but make sure the flatter side side of the valve cover gasket is right, other way and you'll have a vacuum leak. 

Set the valve clearance also.

@siteunseen what nozzles need to move freely? and is it necessary to set the valve clearance after changing the valve cover. I figure even if it was off from before it should still start

I'm sorry I can't help you more now, I'm using my phone. I can help better in the morning when I have my laptop. Maybe someone can chime in before then?

The nozzles are at the very bottom of the carbs and should move move freely with the throttle linkage. 2.5 turns counter clockwise is a base starting point. Mine run best at three to the 3.5 turns down. 

Let me get back to this in the morning,  I'm enjoying some cold beers at the moment.

 

2 hours ago, thosearezs said:

it worked fine until the engine sat for awhile. I put on a new valve cover and a new exhaust. since then I can't get the thing to start.

How long is "a while"?  And where did it sit?  Did you remove anything besides exhaust when you replaced the exhaust?

These kinds of problems are usually caused by the stuff that you're sure can't be the reason.

sounds like gas that has turned to varnish in the carbs, indeed, how long did it sit

Read this thread, http://www.classiczcars.com/forums/topic/39221-quick-and-dirty-su-tuning/

Google images SUs too for reference or go to Ztherapy. Com for more images.

I about to go out dancin' and chasing thongs.  I'm no help. 

forgot to mention i've added about 4 gallons of new gas + additive. im not sure at what rate the new fuel gets mixed in but i've cranked it a a lot since putting new gas in so that may or may not be the case. and it sat for a few months. if i had to put a number on it i'd say 3-4 months

Edited July 3, 20168 yr by thosearezs

and for most of the duration it sat the carbs were off. I'm not denying the gas went to $^!# but it didn't sit in the carbs at least

Everybody's just recommending that you check that the carbs aren't gunked up.  Even a dry carb will get some slight corrosion of the aluminum that can cause friction, if it's in a moist environment.  They're sensitive creatures.  Sometimes it's worse when they're off because they might sit tilted.  Then the varnish sticks on unusual parts.