Warming up issues?

[Pacific coast Datsun]

Ok, Ive noticed lately that it takes a long time for my 620 to warm up. Upon startup i have to keep my foot on the gas for a minute or so to keep it from dying. Also if it sits & isnt ran for a few days i have to shoot a bit of starter fluid down the carb. Im running a 32/36 with elec. choke. I dont think the choke is working right or even at all. Whats the best way to adjust the choke & should i do it with the truck running? Or..could this be something else wrong w/ the carb.?

[Icehouse]

I know what you are thinking, so stop.... haha I do no a little about carbs :) I have noticed on the webers when first starting it in the morning the pedal needs one full compression. This sets the choke, any pumping after can unset it. Try the one pump and report back with the symtoms. O if it starts and dies crank it again sometimes it take 2 cranks, but don't pump it again.. If it goes to 3 or 4 your choke my not be setting properly.

[Pacific coast Datsun]

I forgot to mention that i do pump the pedal once then crank it up. It just idle's so rough it cant be right. The timing is dead on & the points are in good shape. With my 1st motor[same carb] in the truck i'd pump once, fire it up & it would idle high for a minute then after pumping the gas after that would settle down to normal idle. I did notice back in Dec. i had the truck at a higher elevation & if i pumped it once it would flood the carb.

[Icehouse]

Have you taken the air cleaner off to make sure the chock flap is fully closed after the one pump? How does it run after its fully warm? Maybe it just needs a new cap, rotor and plugs. I'm a sucker for tune ups.

[slodat]

If it has an electric choke, it has a fast idle feature as well. This is activated by pushing the throttle to the floor once prior to starting. This is part of the choke system.

 

Also, ditch the points! Immediately. It eliminates a variable.

[Icehouse]

O I remember that part, the manual chokes have a fast idle as well but it is activated by the cable of coarse... I didn't even think to think it was on the electric choke models. Why wouldn't it though, just got a little refeshment. Now next time I take to Hainz I will know a little more about his favorite engine setup. :D

[datzenmike]

Pumping the gas should set the choke plate. The choke plate has a linkage that pulls the fast idle cam into position, and when you let up on the gas peddle the throttle stop comes to rest on one of the fast idle positions, depending on how cold it is.

If the fast idle is set wrong or not working the engine will run (or not) extremely rich. It needs the extra air provided by the fast idle cam to keep it reved up and shorten the warm up time.

If this cam or linkage is stuck it may also prevent the choke plate from closing and doing it's job too.

With a cold engine, not running, air filter off, work the throttle linkage at the carb and observe that the choke plate snaps closed and the fast idle cam now holds the throttle more open when you let go of it. If not work all the linkages and spray with carb cleaner, I use WD-40 but you're not supposed to, as it collects dirt on the linkage parts.

[Pacific coast Datsun]

Thanks for the input. Im off the next 2 days & ill mess with it. I do have an elec. dist almost ready to swap in which will help a bit.

[KB10]

Are we overlooking the obvious? Lets go back to basics. Remove the top from the air cleaner next morning, & depress & release the throttle.

Did the choke actually set? If not, why not? The electric part is just a heating element to make the choke open up again, but if the shaft is stuck, even just a little, then it will not do what it's meant to do.

 

I had this problem with my stock 1200 carb. Aussie models are manual choke types, but the choke shaft is not mechanicly linked to the cable. Instead, pulling the cable causes a snail spring to wind up tighter & close the butterfly. This allows the suction to pull the choke butterfly open a bit if you keep it closed too much & give it some revs.

My choke shaft was stuck & it stayed in the open open position when I pulled the knob out, giving me the false impression that it was working OK. No wonder it was a dog when I tried to drive off in the winter.

 

To fix it, I simply started the engine & warmed it up a little, then gave the choke shaft a spray of cheap carby cleaner. Works like new now, although I gave the shaft a few drops of oil to keep it working smoothly.

 

If I had taken it to a mechanic, I would almost guarantee that I would have been up for a carb overhaul, a fistfull of cash, & a few bus rides over a couple of days while he was systematicly emptying my wallet.

This way it was off the road for about 20 minutes, at an actual cost of maybe $5 [for the fuel system cleaner I also used] & the grin I had afterwards had to be surgicly removed.