253 high idle

[kingswood country]

Well the vac gauge is reading about 15.5" and it's pretty stable.

As said, I believe the float level is correct, it's only just moistening below the sight hole,
and just sitting in the garage it's fine.

hold the revs up for a little while and it's starts dropping the idle and the vac gauge starts flickering a couple of inch

The same as it usually does before it starts doing what it's doing.

On aussie v8s forum, they've also said to take the fuel bowl of and blow it all out and refit, will gasket cement work on putting it back together? Or will I need gaskets?

 

[Dayvo]

I had a similar problem with my 1972 Stato Trimatic . It dropped the revs when put into D. Try going from D into first and see if it selects again . Mine did that . It feels like going from Park to Drive .
Ended up getting a rebuild when it blew all forward gears not long after.

 

[Aussie V8]

Well the vac gauge is reading about 15.5" and it's pretty stable.

That says to me, assuming your engine is in good condition, that your timing is out.

On aussie v8s forum, they've also said to take the fuel bowl of and blow it all out and refit, will gasket cement work on putting it back together? Or will I need gaskets?

Don't use gasket cement on a carby, get the correct gaskets for it and use them. Most are once only use but you can get multiple use gaskets for Holleys.

What power valve does it have? Is the power valve open at all when the vehicle is idling? If you have fuel going in via the power valve before the issue starts that could explain the need for you to use the choke to get it running smoothly when the problem occurs. I'd set the power valve to 1/2 the idle vacumm reading so for 15"HG idle I would use a 7" or 8"HG power valve.

 

[kingswood country]

I don't understand how that'd make the carb/fuel system play up.

It shouldn't be the auto anyway, it hasn't done too many kms.

 

[kingswood country]

Well the vac gauge is reading about 15.5" and it's pretty stable.

That says to me, assuming your engine is in good condition, that your timing is out.

On aussie v8s forum, they've also said to take the fuel bowl of and blow it all out and refit, will gasket cement work on putting it back together? Or will I need gaskets?

Don't use gasket cement on a carby, get the correct gaskets for it and use them. Most are once only use but you can get multiple use gaskets for Holleys.

What power valve does it have? Is the power valve open at all when the vehicle is idling? If you have fuel going in via the power valve before the issue starts that could explain the need for you to use the choke to get it running smoothly when the problem occurs. I'd set the power valve to 1/2 the idle vacumm reading so for 15"HG idle I would use a 7" or 8"HG power valve.

I can only assume it's good, The engine itself is great, but I've never had the heads off, so they're an unknown quantity,
The timing is set by ear, I don't have a timing light, I have the ignition on and turn until I hear a click, advanced slightly from that, and that's where it's at.

As for the power valve, I've got no idea, I wouldn't even know where to start, I've only read a little about this tonight.

Its been running fine for nearly 2 years until a week ago.

At the end of the day, I won't be spending anything on it, there's better heads and a quady in the process of going on. It's just getting annoying.

 

[Aussie V8]

I can only assume it's good, The engine itself is great, but I've never had the heads off, so they're an unknown quantity,
The timing is set by ear, I don't have a timing light, I have the ignition on and turn until I hear a click, advanced slightly from that, and that's where it's at.

As for the power valve, I've got no idea, I wouldn't even know where to start, I've only read a little about this tonight.

Its been running fine for nearly 2 years until a week ago.

At the end of the day, I won't be spending anything on it, there's better heads and a quady in the process of going on. It's just getting annoying.

Your vacumm reading indicates there is another problem somwehere. If it's not the carb it is either ignition timing or maybe even cam timing or a lobe ground off the cam itself. I'd hazard a guess that cause you time it by ear the ignition timing is out. No use putting anything on it (heads, quady) until the ignition timing at the very least checked with a timing light. If you know that the ignition timing is ok after doing that you will need to look at why the vacumm reading is only at 15.5" HG.

 

[kingswood country]

Either way, the Holley is no end of trouble, I haven't heard a single good review on the Holden v8, so it will get a quady, I'll try and chase one up, but it still doesn't explain why it's fine for half an hour then not. Especially since the timing hadn't been touched when it first started playing up.

 

[Aussie V8]

I agree there is a problem with the Holley but it seems that you may be chasing your tail because there are other issues as well which mean you will never be able to fix the, possibly very minor, problem with the Holley because somethign else is very screwed. As for not explaining why it is ok for 1/2 an hour and then not ok there are a myriad of things that could explain it.

I have seen good reviews for Holleys on the Holden V8. Commodore Cup cars use them and many other people use them becuase of their simplicity. They are an easy carb to work with and they are easy to tune. For a Quad you'll need to jet/rod it down for a 253 and if there is a problem, like I suspect, you will have difficulty getting things ok with a Quad too.

 

[kingswood country]

I'm just talking from personal experience and others I know, they're a good carb, just not on a Holden v8, there's always a flat spot somewhere.

The top end will all be new once the quad goes on, it'll be jetted down with new rods and overhauled before putting it on, and by that stage I'll have a timing light. But I'll keep playing and see if I can get mate with one to get that timing right..

 

[VR38]

I'm just talking from personal experience and others I know, they're a good carb, just not on a Holden v8, there's always a flat spot somewhere.

You sound serious haha, a holley knows the difference between a Fraud, Holden or Chev???