My problem-

Was driving , I let off the gas and the rpm shot up to about 5k and would not go down. I took some advice that it was the dashpot and to just remove it.

I did, but I started the car and the rpm when immedately to 4k, so I shut it down. Looked like there was some slack in the trottle cable, but the throtte would not close anymore.

Not knowing what to do I removed the carb. And stared at it. I don't know what year the carb is from as the it is not the original (Car is an '81), but I it has larger primaries than the carb on my '84.

1) What could be wrong with my carb?

2) Are the larger primaries better (ie more power)?

3) Are carb rebuild kits year specific? There was a rebuild kit in my '84 when I bought it, could it be used on the carb with larger primaries.

Please help me not hate carbs!!!

 

1) Look down your carb throats and determine what butterfly is stuck slightly open. From there it's pretty easy to trace what linkage is giving you a problem.

2) I dont remember the primaries being any bigger on earlier carbs... they had slighly bigger primary airhorn barrel diameters, but that's about it. It's the earlier manifolds that are "supposed" to flow better.

3) Year specific.

 

thanks,

I should have been more specific, the airhorn bigger...


How do I fugure out what year carb rebuilt kit to get?

 

call an automotive store around you and ask for one, they probably have to order one... or check some local garages, they may have access to some...

 

According to the local auto store, carb kits are all years.

So, I tore my carb apart. And did it take a long time. I suppose it was in reasonable shape, but I am glad I did it, learned alot.

I did find my problem, but not the solution. The Primary butterfly was not closing all the way.
Why? There is a throttle stop screw on the opposite side from the throttle linkage and it is hitting that, even with the screw back right off. Any ideas

 

That screw is your idle adjustement. The primaries arent supposed to close all the way... if that was the case, you're car wouldnt idle. I'd be looking for stuck secondary or fast idle linkage. Get yourself a shop manual (if you dont have one already), that should help you out. If you're really stuck, you can ship it to me... I rebuild carbs .

 

How many mm or inches should the primary butterfly be open for idle?

My understanding (from Haynes) is that the fast idle should have the primary cracked open 1mm. Of course it is completely possible I misunderstood- this is my first crack at carbs beside my kart.

Thanks I appreciate the help!

 

Hey Duck... Was it VERY hard to rebuild the carb with the kit? I want to rebuild but i'm afraid it's gonna be too hard--one reason is because i'm not very familiar with carbs

 

It's not hard at all. Just make sure you have a nice clean work area so you don't lose any of the little bits and pieces.

 

can you make the carbs actually better?like paul yaw?

 

Sure... I rebuild and race prep them (remove all unneeded hardware), but I'm currently in the process of determining what flow/internal mods actually work.

Anyone with Dellortos can check out my write up at www.gruntled.com/Dellorto/Will-Jetting.html

 

FUllofsmoke: I had never done it before and it is was not very hard, but it is time consuming.
Clean/large work area (like a big table) is a must. I had a bunch of small paper cups that I put the parts in, labeling each cup with the corresponding step in Haynes manual so reassembly was easy. Just have a fresh can of carb cleaner and couple of ice cream buckets for cleaning.


RXcetera: The carb is actually for my RX7 that I ice race in a spec 7 class. Most of the emissions stuff had been removed. If this carb doesn't work out, maybe I will be talking to you.

 

hook me up.how much?have stock nikki.

 

100-200$ depending on what you want. 100$ for a straight rebuild, 150$ for rebuild/cleaning/polishing, 200$ for all that and mods.