wrightbenz

Hi guys, continuing on my resurrection of this 83 with 45k original miles that has been stored for a really long time.

I have the car running now after removing the fuel tank having it cleaned and installing a new fuel pump. The car was running fairly well sounds healthy, but of coarse as expected there are some issues. I have been going slow with this and after letting the car run at idle for some time I decided to head to the gas station for a first trip.

The car would run well and then stumble and stall. I kept driving her taking my time figured it may get better. After 30 minutes or so I decided to giver her a rip and ran her up to 6k or so seemed pretty good.

Now at start up she revs up to 5k like something is stuck but everything seems fine mechanically on the carb. Stock nikki. My guess is that the carb needs a rebuild accelerator pump has gone wacky or something but I am not sure.

What do you guys think?

t_g_farrell

iTrader: (1)

I think a good carb cleanout and rebuild is in order. If you had to clean the tank and replace the pump, odds are
junk got up to the carb too.

j9fd3s

iTrader: (3)

if its idling that high, there must be a big air leak/something stuck open in the carb.

wrightbenz

Nothing like that I have checked. Car was running fairly well and once I opened it up is seems like something failed in the carb. I am not to familiar with carburetors so I really have no idea, but it seems as if something just went.

wrightbenz

So I went ahead and removed the carb for a rebuild. I did this for two reasons. One the car was stumbling and stalling anyway. And two my thought was that the high reving is somehow related. This may or may not end up being the case but if figure digging in would turn some stuff up and it has.

First what is this butterfly valve in the intake under the carb?



Pics of the carb removed.

What is this metal cap? It is loose.

t_g_farrell

iTrader: (1)

Butterfly is the coast down butterfly and the cap is to prevent you from messing with the mixture.

You should get a look at the carb manuals on this site foxed.ca, they will explain much.

Also if you browse thru my Fat Nikki thread in my link it may explain some of it as well.

wrightbenz

Thanks I was reading the manual last night.

Any idea what may cause the engine to race to 5k rpm ? I seemed to be carb related to me.

j9fd3s

iTrader: (3)

you need a lot of air, and enough fuel for it to run, so you're looking for throttles jammed open, or some such.

if it was just an air leak, or just fuel the thing would probably have a hard time running

wrightbenz

I agree. It was really strange . I did not see anything stuck open I am guessing I have some sort of large vacuum leak but did not see it. The carb needed to be cleaned up regardless but I may find I still have the issue once I reinstall it.

Jeff20B

iTrader: (13)

Hot start assist linkage might have gotten stuck.

NCross

iTrader: (18)

Time for emissions removal! Hot start assist causes problems too, but usually flooding after you shut the engine off it will crack the throttle plates open and dribble fuel into the engine.

Is the throttle opener capable of that kind of RPM? They do get sticky after 30+ years.

wrightbenz

Where is this linkage ?

Jeff20B

iTrader: (13)

Looks like you have three cables. It's one of them. Follow each one back to where they begin. One of them is the hot start assist.

My car doesn't have one because it started life as a GSL-SE. I swapped a Nikki in it because carbs are better (the stock GSL-SE's EFI is better left to folks like Long Duck who like stock power levels and want to keep the car stock, plus mine was missing when I got it). I didn't swap a hot start assist motor in though. Not necessary if you have a foot and know how to use it.

It only works in "Start" mode anyway. As soon as you let off of the key, the motor stops tugging on the carb so all you have to do to mimic its function is to slightly open the thottle during cranking.

So there you have it. A Nikki working fine without a hot start assist. Like NCross said, time for removal of unneeded 30 year old parts that don't work properly anymore.

Jeff20B

iTrader: (13)

Or it could be the hose that always leaks on the rear rotor secondary intake manifold runner. It gets heat from the exhaust manifold which degrades the rubber. I don't know what it's called because I've never had to deal with it. But yours might be leaking.

Download the FSM if you have't already. I guess a link to it is a sticky at or near the top of this section. I'm sure that's not super helpful but I have a haynes manual so I've never needed to download an FSM.

wrightbenz

Have the fsm thanks. Is this hose you are talking about a vacuum hose?
I picked up another nikki off a good running car and it came with a rebuild kit. Now I Can rebuild mine when I have time and use the other til then.

Jeff20B

iTrader: (13)

I think it's called the anti-afterburn hose. It goes up to something connected to the carb or the blue air cleaner assembly. Kind of a big diameter hose like 3/8" or 1/2" in size.

wrightbenz

So I picked up another Nikki that came from a running car. It came with a rebuild kit so I figured I could rebuild my carb and in the meantime run the other unit. Car starts now and idles at around 1400 rpm with the used carb. The bigger issue is when I drive the car it goes for a block or so and then just seems to run out of gas and stall. It always restarts but sounds strange, when the starter is engaged like one rotor is firing and once started power feels low like only one rotor is firing.

Any help here would be great. The car will idle fine runs fine until it's under load. Not sure if this is a carb issue? Possibly not getting good fuel pressure ?

Should I see fuel spraying from the top of the primary's in the carb? File is just dribbling out of the top or the air horn sorry not sure wht this is called. I think the primary's are further down inside the carb though. Where I see the fuel dribbling out I beleive is for acceleration.

j9fd3s

iTrader: (3)

this. its been a while since i've seen one that worked, usually they are just dead.

at the dealership we called it the mystery hose... N201-13-756 i think.

the function is to supply fresh air to the rear rotor when the shutter valve is closed, so it isn't really a vacuum hose, although it is made of rubber