12A stumbles, rough both hot and cold
 

Suddenly, my 83 12A NA runs rough when I start it for 15 secs, then smooths out. Almost like the shutter valve, except I've go that plugged. Doesn't matter if it's hot or cold. Also emits some white smoke. Does this mean I've got a coolant leak?

B

i know that white smoke is burning coolant, but does it smoke just after starting for a few seconds or all the time? if its all the time its possible that your water seals are going. im not sure but it sounds like it could be something carb related to me. wheres rx7carl or sterling when you need them :)

It only smokes when it starts up. While it's stumbling. Then, 15 secs later it smoots out and the smoke disappears

B

If it's just those manifold O rings it's not too bad, but I'm concerned that it's the internal water seals.

B

hmm im not really sure cause and i dont want to guess so maybe someone with more experience can help us out...

Probably just the O rings. You can't be sure it's the engine seals until you change the rings out.
(Pretty much have to have beat the piss outta yer engine to get the water seals to be bad.)

I treat the car well so it shouldn't be the internal rings. But it is 20 yrs old with 120k, so I suspect it's the O rings, especially since the O rings under the beehive are obviously shot (I have the replacements ready to put in - just need time).

B

It sounds like you are having the same problem that i am. When you start it, does it take a while to turn over? Whats happening to me is something is causeing my engine to flood when its just sitting. My rear float was acting like a boat anchor, and my carb was just shooting gas down in my engine. I fixed that, but its still doing it. The more i think about it, the more i think i might have killed a water seal. *shrug* Luckily i have a parts car thats engine supposivly works..... In short, check your float levels, and air/fuel. Pull your plugs and see if you are running rich of lean. And make sure that all of your plugs are firing.... after that you should be as stuck as i am....

I don't think it's the carb, because it starts right away. And I lose a cup of coolant every week or two. I'll check the plugs to see what they look like. But right now I'm guessing the manifold O rings.

B

While I'm changing the O rings, ought I put in a new manifold, like maybe an RB? Does RB make an intake manifold for the Nikki?

Looks like replacing the O rings is a headache, involving removing the Niki, detaching all the hoses wires and cables, undo the manifold and worm it out, etc. Is it as bad as it looks?

B