Slag02

The other day my supervisor rode in my car and noticed that he didnt hear my secondaries open.. I said HMM.. So today We (my uncle and I) had a look and the secondaries are just staying open the whole time...

When I try and Punch it it boggs down for quite some time.. and i have read on here that means its running lean... My uncle said he hadnt workd on a carb. in ages but he said it looks like the linkage from the throttle (maybe) was missing to the secondaries he also said the the secondaries should be facing the windshied not the Nose but hes kinda old (to me im 20)

Heres some Pix

My carb. is a
Holly 750CFM DP
4779-7
3099

Any Help???

Slag02

Pic 2

Of Whole Engine.. It was kinda bright today Sorry

todd200

Your secondaries are facing correctly toward the back of the car. Really need a pic of the linkage. I doubt your secondaries are open all the time. Your idle speed would be REALLY high.

P.S. I would try to reroute that fuel line away from the alt belt.

TPI-454

You'd have to stare down into the Carburetor to know this for sure. Are you?

If you're boggin down for quite some time, then you're mechanical secondaries are opening way to soon. You need to adjust it's (the secondaries) linkage to open much later.

You're uncle is looking at the Carburetor backwards, as the secondaries 'are' facing the windshield, and it's linkage is on the drivers side.

Slag02

My Boss at work just looked at it and said almost the same thing..

he said that i should make the linkage longer so that they dont open so quick.. my only issue is...
How would i do such thing??

TPI-454

You can't miss it. While you're underneath the hood looking at the Carb, with you're hand... open up the throttle manually, and carefully look for an armature that is 'linked' to the throttle linkage (leading to the secondaries, over towards the side-rear bottom of Carb base)...

Once you find it, adjust it, then use the ole trial and error method (test and tune). You'll know when it's adjusted right, because it'll pull nice and hard.

Remember, the later the bog, the closer you are. Keep adjusting until the bog goes away....

todd200

Or he may need more pump shot. Can you see what size the shooter is? What color is the pump cam?

TPI-454

If it were the accelerator pump though, the engine would be 'idling' a little rough... along with the corresponding bog.

Apeiron

The accelerator pump won't affect the idle at all.

TPI-454

A leaky one will...

Apeiron

How does a leak affect the idle?

TPI-454

A failed accelerator pump will cause a tremendous bog moving 'off' idle, but tends to make little difference above twenty percent throttle.

As for a shot, or leaky, accelerator pump not affecting a good idle... it's not a very noticeable effect, it simply affects idle mixture, which in turn causes the bog due to insufficient fuel.

There's normally three things people look for, with that type of symptom (bog);

Secondaries might need adjustment.

Accelerator pump is bad.

Vacuum leak.

Apeiron

What I'm looking for is how a leaking accelerator pump affects the idle at all?

todd200

Slag02, DON'T bend anything. That is a something you can do but it's not exactly correct. When does the bog happen exactly, from a stop, roll, etc. When it bogs does it backfire through the intake? Either way check the float level in both bowls first. If that is incorrect, nothing will help. Set the level to the bottom of the sight plug hole. See what size the shooters are. See what color the pump cams are. Stock shooter size is 28 primary and 31 secondary on a 4779-7. I had to step mine up to a 31 primary 38 secondary and pink cams in the #1 hole to get over the bog on my 600. I don't know what the stock pump cam color is on a 4779-7. Try to give a detailed description of what exactly is happening so we now what we are trying to fix.

If you want you could call 270-781-9741. That is Holley's Tech Line.

TPI-454

Okay, I now see where you're going with this... but I'm not going to bite.

Any tips for Slag02, Apeiron? Or would you rather just waste a little more time with words disguised as some coherent point.

Apeiron

I'm not going anywhere. If a leaking accelerator pump can cause a change in idle mixture, I would like to know how.

todd200

If the discharge needle(s) were missing I could see a leak through the discharge nozzle causing an overly rich idle. A couple of new needles and a rebuild kit and it's fixed. Otherwise pullover could do it, but I doubt a 750cfm carb on a 350ci engine would have enough signal to have a pullover problem.

Slag02

Wow I missed alot in my own Thread.... and btw it is a 355 lol

Well heres whats going on... from idle 1st Gear... if i SLAM On the gas.. I get a Major Bog for quite some time... If I have the Engine revved in 1st Gear Not as bad as idle bog but still some...

My Supervisor at work also said that i might need to get smaller jets on there.. he wasnt sure... He said a Master Rebuild kit should come with different jets and would probably fix my problem.. he said what my uncle thought was running open all the time was accutally my choke but its not connected so its open all the time....

Now If i was to rebuild the carb.

I have never ever done it before so... im a little nervous because i dont want to break anything.. he said to give it a weekend and then after you do it once you can do it in a night with some beers..

Any other help is much appreciated

Slag02

one more thing.... my vaccum advance is NOT hooked up because when i do it runs REALLY funny... so thats just another thing
you can see the blue cover in the upper right part of the Carb. In the Pic

todd200

Your jets are not your problem. When you say "it runs funny" with the vacuum advance hooked up what do you mean? What does it do, how does it act? If the history of the carb is unknown I will second the rebuild. It's not bad at all, just pay attention to what your doing. Buy a Holley book. I'll get you part # ASAP. Does your bog Happen all the time or only when the motor is cold? It sounds like you have tip-in hesitation. It will be much worse without a choke on a cold motor. Does it backfire when it bogs? I'll check this ASAP.

Slag02

I havent Hooked up the Vacuum advance in a while from what i remember it sounds like the engine is choking for air... like its short of breath.. I cant get Much Acceleration.

The Bogs happens all the time Hot or cold... and No it does not backfire when it bogs.


anything else

Thanks

five7kid

iTrader: (14)

The vacuum advance helps the engine be more efficient in street operation. It shouldn't be a factor for these WOT issues if everything else is adjusted properly.

You probably have some ignition issues, such as timing not properly set. The fuel line is a major hazzard and should be rectified immediately. (Speaking of fuel lines, it looks like a 4160-type dual feed line was forced onto a 4150-style carb - an indication that other things may also be wrong.)

Otherwise, start with the basics: Fuel bowl levels proper, accelerator pumps working properly, power valve not blown, jets in a "reasonable" range (the Holley website has a list of the parts used when the carbs are shipped), etc. If you don't know the basic condition of the carb, take it apart and find out. A torn piece of a former gasket blocking passages can cause all sorts of problems.

todd200

I would get Holley Model 4150 & 4160
Carburetor Handbook part #36-133
http://www.holley.com/HiOctn/Sales/S.../SrvLtrtr.html
It's about 2/3's of the way down.

Slag02

Should I get the master Rebuild kit as well???

todd200

I would get a Trick Kit at the same time. Read the book first. That way if you come across something on the rebuild you will be able to identify the problem. Something you would have passed over you would hopefully catch if you read the book before taking the carb apart. Also, make sure as five7kid said, your ignition is in good shape. Otherwise you'll be fighting a "carb problem" that doesn't exsist. I would suggest a rebuild on any used carb. That way you know its right and the Trick Kit also comes with some tuning parts that will save money in the long run. Make sure your ignition is tip top, buy the book, rebuild the carb, and take the time to correctly tune it, and you will be rewarded with a good running car.

Slag02

Im Pretty sure the timing is ok I have no rough idle... I think If I did hook up the Vaccum advance then I would Need to Adjust the timing....

The spark pulgs and wires were last changed in July of 2003 but i have only driven the car probaby < 200 Miles since that date is that an issue... I started the car At least once a month during that time frame.. Always fires right up.



And what exactly is the trick kit and what does it do?


Thanks

todd200

Just because you have a good idle doesn't mean you don't have too much or too little timing. What is your base timing and what is the timing at 3000rpm? Why do you think you would need to change it if you hooked the vacuum advance back up? This is what you need:
http://store.summitracing.com/defaul...=egnsearch.asp
Holley part # 37-485.

The Trick Kit is a rebuild kit that also has an assortment of pump cams and other tuning parts. Unfortunatly I don't see one on Summit. The Renew Kit may be the same thing though. Might call Summit and ask.