another idle issue

[canadian nascar]

Hi Guys,
I have a 301t with 8.5 compression, 262 comp cam, stock carb 276 export

I have a a/f gauge that I am adjusting to,
stock hei with accel coil
made the carb specs to Cliff's recipe #2, Cliff suggested this
-14 vacuum in park
timing dist is locked right now at 18* with 25* vac adv.
I have gone though the lines numerous times looking for vacuum leaks

I the car idles but higher rpm, 800 in gear to keep it running, sometimes feathering the throttle, if I put the a/f to 15-1 it will be hard to start and puff fuel out the exhaust when it does start. Really gassy
To make the car not puff smoke I lean it out to 17-1 a/f, it starts better and no puffs of smoke, same rpm as above, still gassy

I bumped the adj vacuum adv just before I but it away to 25* and it made my vacuum increase, I thought this is a good thing and would like to give it some more vacuum adv. but I was told that is not right. The gassy is less with more adv and like i said gave more vacuum.

it will not run without vacuum adv.

when I start it cold the exhaust smells like it should for a minute or two.

what other info is needed and what can I do ?

Kevin

[77cruiser]

Have you tried adjusting the idle to the highest vacuum? It will end up a lot richer than 15-1.

[canadian nascar]

so you are saying just to adj the idle speed screw to highest vacuum, in my case slower rpm?

thanks

[Cliff Ruggles]

It may not like the Comp cam.  Those cams idle "quirky" in larger engines with more compression than the little 301. Never liked them much and 110LSA is just all wrong for a Pontiac engine, IMHO.

If you are having to run that much timing at idle to get it to stay running, for sure it either needs more fuel down to the mixture screws to offset the poor signal to the carb.  I'd start there, and see if you can back the timing off some and get the throttle plates open a little further at idle as well.......Cliff

[77cruiser]

so you are saying just to adj the idle speed screw to highest vacuum, in my case slower rpm?

thanks

No the idle mixture screws.

[canadian nascar]

Thanks Guys,

 will try this, I hope I can get it cleaned up some without changing the cam.

Kevin

[canadian nascar]

Hey Cliff,

Just wondering if the comp 262 cam isn't a good choice what would be a better choice, I have had references to a comp 252 cam but the LSA is still 110.

do you have any preferences?

thanks Kevin

[Cliff Ruggles]

I am NOT a fan of any of those short seat timing tight LSA camshafts.  You'd be WAY better off with a Summit 2800 cam, gentle ramps, easy on the valvetrain, and wide LSA......Cliff

[canadian nascar]

hey Guys,

car is out and looking at the carb the right side " nozzle " i think it is called is dripping fuel, the little tips inside the circle casting primary side. but the left side isn't, touch the throttle and both side squirt.
the fuel screws are out 2.5 each,
the a/f is 16-1
float height is 5/16
110 gph holley pump 6.5-8 psi
idle 900 rpm a little rough

later Kevin

[Cliff Ruggles]

I would back the idle mixtures screws out some.  Those later carbs have very fine metric threads and very small holes under the mixture screws.  We usually have to back them out 4-6 turns or so to get enough fuel to those engines at idle speed...Cliff

[canadian nascar]

hey guys,

changed the float level to 15/32 as spec says, and 301garage forum, seems to have more vacuum and I turned out the mixture screws 3.5
a/f is 15.5 idle
vacuum 16
rpm needs to be lowered from 1100 to 800
no nozzle drip now
not puffing fuel and as much gassy stink at idle
running better

later Kevin

[Cliff Ruggles]

Good news.  High fuel pressure often requires a lower float setting, and 3.5 turns out with the mixture screws on a later carburetor really isn't very far, especially if you didn't open up the holes under them.

The 110LSA will be a bit "stinky", especially in such a small engine.....Cliff

[canadian nascar]

Hi Cliff,

The holley 110gph pump is rated 6.5-8 psi, would a regulator be a good choice and what is the optimum psi for a quad

thank you Kevin

[Cliff Ruggles]

It should be fine without a regulator, those later carburetors can easily handle 6-8psi with the .135" inlet seat and stock float......Cliff