Now I am getting somewhere

[strat1960s]

Cobra,

Make sure you have some extra intake manifold gaskets. If you have a leak it could take some time to get a new gasket.

I am going through many of the trials that Jimbo is. I have to fix what is on my list now in order to find the things I need to fix on my next list, and on and on. Who knew it would be so much fun....LOL.

Ted

 

[CobraSix]

I'm going to buy some gasket material and make my own. Not that hard.

What kind of problems are you having?

Slade

 

[Anonymous]

Jimbo;
From your descriptions, I'd bet $$ on a vacuum leak.
In particular: you mention how it likes to die when idling down from a highway run, with white plugs - classic vacuum leak, just above idle range.

Things to check in that range: 1. hole in distributor vacuum diaphragm, 2. hole in power brake booster (in you have one), 3. (auto trans) hole or worn-out vacuum hose going to the vacuum modulator on the trans. One other possibility: if your carb is a 2-piece design, like my Holley, the lower "half" of the carb can loosen up and introduce a vacuum leak that's above the throttle plate, so it would idle OK, then have trouble above idle.

Long shot: I have also found holes in vacuum lines that were only found by replacing the %*$*# thing, then playing with the old one under a hi-intensity lamp - although, if I'd had a hand vacuum pump, this search would have been easier.

 

[Anonymous]

I am leaning towards a vacume leak too, problem is I cannot find it...

I think I can even hear it, slight hiss around the carb, I have tried using oil to see if I can stop it, tried using a hose to listen to the eges of the manifold. I am also using an adapter plate under the Holley, there could be a leak in there...

I am going to pull the carb over the weekend and try sealing the lower gaskets to see if that is the problem... I have some spares for those.

as for the manifold gasket itself, I cannot see that leaking, it is sealed very tight... but at this point anything is a possibility.

as for the lines, they are all new and I do have a hand pump.
the booster is not leaking, it is also new... and I am pretty sure the booster is not the culprit...

I pulled the water lines running through the manifold and capped the ends.. so it seems unlikely they are the trouble... I had the manifold fluxed and checked for cracks and one was found and fixed prior to coating, so I am reasonably sure it is fine...

I am putting money on the carb adapter...

 

[Mustangaroo]

Jimbo65,
The most common vacume leak is the manifold gasket! This has been the biggest problem I have found with the Aussie 2v change. I started making my own gaskets using thicker material, this fixed the problem! Just the smallest leak will cause a cylinder not to fire at idel If your engine won't idel at lower RPM start by pulling off one spark plug wire at a time, engine should run rougher on all cylinders except the one with the vacume leak as it is not firing because of the lean condition caused by the leak! The current gaskets for Aussie 2v are very thin, go to you local parts store and get some gasket material and cut your own, there better and lots cheaper! Good Luck.....

 

[Anonymous]

I coated mine on both sides with the copper permatex.

 

[Anonymous]

I was thinking about the permatex.

I used a plain High-tac sealant around the gasket, which according to some articles I have found is crapola...

seems like RTV is not gasoline freindly and only an avaition level sealant is recommended for intake gaskets, or copper sealant...

I will try the plugs in the morning, sounds like you are right on the mark, I am sure there is a cyl missing at idle causing the rough idle.

Sometimes you have to go around the block to get to the neighbors.