I have just performed this swap on my 1990 Jeep Wrangler and I haven't made the linkage yet. However, I have a question. It sounds like I have a big big vacuum leak or something. I haven't connected the pcv vacuum line yet. What other lines are necessary to connect to the carburetor? Also, the vacuum is really loud.. I don't think that the fact that I don't have the vaccum lines connected yet are causing this. I'm not too familiar with carburetors yet so bear with me. Do the idle screws on the front affect the vacuum at all? Like I said, it is a loud vacuum sound. I have good seals in between the carburetor and the adapter. What do I need to do?

Thanks

Originally posted by khsjeepr
I don't think that the fact that I don't have the vaccum lines connected yet are causing this.


WRONG!

What do I need to do?

Hook up vacuum lines or put caps over the ports. Then report back to us on how the Electrolux magically disappeared.

The normal engine operation actually pulls a lot of vacuum too, so if you hear vacuum down the throad of the carb through the venturis , that's normal.

Check the baseplates. I have heard that some carbs do not fully cover the openings.

Do you have the air cleaner on it yet? My 258 sounds like a tornado if its running without the air cleaner on it.

John

Before trying to tune the carb you MUST have the unused vacuum ports capped and put the air cleaner on with gaskets between the rim of the carb and your cleaner base. I had to use a spacer for the air cleaner so two gaskets were needed. How thick of a carb/manifold gasket did you use? Is your manifold straight? If all the ports are capped and the base gasket is making a good seal you should be just fine.

The manifold should be straight as it never leaked before. I have one question. I haven't ran the pcv filter onto the back of the carburetor. I plugged off the hole and instead ran a separate filter on top of the valve cover for the pcv filter. Could this be my vacuum leak?

Still trying to fix vacuum leak. Any other suggestions as to what it might be? Or how to fix it? Like I said, I have all the vacuum lines either running into the carburetor or blocked off. What do I need to do now??

Use some carb cleaner and spray a little at a time around the base of the carb, vacuum ports, etc. The idle should change when the cleaner is sucked into the leak. That should pin point the problem. All unused vacuum ports must be capped.

Could it maybe just be the difference of the carb pulling in air or something? I mean, I wouldn't think so but anything is possible I guess. It is pretty loud. Thanks Jay, I will try the carb cleaner trick this afternoon.

Remember to put the air cleaner and everything on before you start checking. This will lesson the noise from air being sucked in through the carb.

I've never tried this, but I once heard of using WD-40 to find vacuum leak.

With engine warmed up and running, lightly spray WD-40 around fittings, manifold, gaskets, etc. Anywhere you might think there is a leak.

Do this one by one, instead of all at once.

If you have vacuum leak, the WD-40 will cause RPM increase when you find the spot.

Good luck.

~JM~

Do you guys think that if I used RTV instead of the gaskets that came with the apapter, I would be in better shape??? Or should I just use a combination of the both? I'm looking for more info on why it has a vacuum leak...

So you have pin pointed the leak at the adapter? Be sure that the adapter properly covers the base of the carb. A little rtv may help. It can't hurt.

I wouldn't use RTV, use the copper Permatex gasket sealer. It comes in a spray can.

Also, you're not giving enough details, did you try the spray at the base, is that it or not???? :rolleyes:

Use the right stuff for gaskets and you won't be sorry..never chase vac leaks again.


the right suff is...
http://www.permatex.com/right_stuff/right_stuff1.asp

I use a propane torch with a copper tube that I can bend and get around to hard places or under intakes to check for leaks.
uhh..don't light the torch if you wondering.. just use it as a sniffer and if there are cac leaks it will absorb the propane and you'll hear the engine respond . I use a digital tach and watch it as I search