Carb Problems Again - Boy Can I use Some Help

[palerider94]

Bought the car about 2 months ago. 1970 302. Had an old 600 on it - Was running real rich and eventually car kept flooding out. Could not adjust the floats any more down. Instead of rebuilding bought a new Holley. It ran great for a couple weeks and then this Friday it started flooding in the back jets. After I drove it a little bit it was okay. Went to drive Sunday same problem. Took it back to auto parts store and they gave me a new one. This time I put a clear fuel filter between the pump and carb - did not have one it previously - thought that may be the reason other carbs going bad.

In any case put the new one in on ran a little lean. Decided to take a test drive last nignt and car died and would not restart. Sounds like it wants to start - gets a little gas from accelerator pump - but that is about it.

Any help in diagnosis would be appreciated - I thought I had this problem fixed and not quite sure what to look at next. Will pull filter off and see if it will start.

 

[palerider94]

Forgot to mention not sure if it matters but - the car has a relatively new tank on it - was put on by previos owner.

 

[jdowen2]

Go back to basics...check fuel, air, spark.

 

[jbuening]

If the filter is one of those cheapos from the parts stores that have a plastic screen tube inside, then throw it away. It let more junk past it than it caught in my motor. Agree with the basics, check to see that the spark plugs are getting a good spark. Also hook up a timing light and see if you are around 36° total (initial depends on the weights in your dizzy). If those two are good, make sure you are getting fuel to the carb. If you are getting fuel, you may have junk in the carb that is blocking some of the passages.

 

[palerider94]

Checked fuel disconnected line from carb - blew out filter turned over engine and getting gas out of the line.

Just before I headed off to work I tried starting one more - held foot all the way to floor kept ingnition key turned on and cranked the engine - thought I would hear starter back talk instead car fired up - needed to set idle up a little but runs smooth.

Since I don't know what the previous problem was - talk about not trusting to take it out on the road. Any ideas on where to look?

 

[jbuening]

Carb was flooded IMO. Whenever it wants to start but won't, hold the gas pedal to the floor and try to start it. If the carb was flooded, 9 times out of 10 it will fire with the pedal to the floor. Glad you got it figured out.

 

[chepsk8]

Sounds like time to go through the carb. Set the floats, probably re-jetting needed. I had a 600 cfm Vac secondary on Chepie, with a stock 302, I had to reduce the primary jets to really make it run good.

I would also check your intake manifold & other sources for vaccuum leaks.

 

[palerider94]

Thanks for all the replies.

I thought it may be flooded too when problem occured last night - 9pm. Took for a test drive - was not a pretty site stranded a mile from home with no cell - fortunately a county cop was there when it died out. Could not get started for nothing. Had to have it towed home. Wife only comment was put it on Ebay. Very understanding.

Anyway the filter I have is a glass one that has plastic filter I got from Autoparts store. Is that one of the cheapies and should I upgrade and too what?

Also I wondering should I have a filter before and after the pump or is that overkill?

I was going to check float but looks like they changed the setting on newer Holleys - the old ones had an adjusting screw on top. Did not see one on the new one? I'll have to do some research in this area.

Finally, thinking about getting a trailer to tow car. Have a feeling it may come in handy util I get all the bugs out - I was thinking something like the ones u-haul rents - any suggestions on this too?

Again thanks for the help.

 

[rufusbooth]

I had the same problems that you are having…

New tank and pickup.
New fuel filter
Carb would still flood.


Basically the Carb needle and seat would get hung open and dump fuel when the car was running.

Steps to resolve the issue:
1. Purchase a filter to be inserted between the fuel pump (I am assuming you have the stock block mounted pump) and the carb. Throw away the clear filter you currently have and go to the “filter wall” in your local parts store. Purchase a paper element filter. They will either be in a white plastic case or a steel one. Just look for the biggest body that will fit on the installation area and still has the same fuel line sizes necessary. We are looking for the largest paper filter we can fit.
2. Purchase a NEW fuel hard line to go between the newly installed filter and the carb. There should be NO old fuel line between the new filter and the carb including any rubber line.
3. Remove your current carb and thoroughly clean the float bowls including the needle, seat, and fuel inlet track with carb cleaner.


You are having a problem with old Varnish breaking off the interior of the hard fuel lines. This Varnish is thin, clear, difficult to detect, and almost impossible to remove. These small particles of varnish are traveling through your current crapy filter and lodging between the needle and seat in the carb. This is allowing unchecked fuel to enter the carb. That is why you could not adjust the float levels down enough. The fuel was leaking past the seat.

In this case the more efficient filter will catch this particulate matter (better filter media) and due to its larger surface area it will last longer as you will have quite a bit of crap coming out of the system. This will only help BEFORE the filter. It does nothing for the lines AFTER the filter.

We are replacing all of the hard line between the filter and the carb because there is no protection between the carb and filter. This hard line caused me MONTHS of grief. That little 2 foot stretch of line was the bane of my existence.

Trust me on this fact…replace that line, put in a good filter and your troubles will go away.

Cheers,

Rufus

 

[jbuening]

I bought one of the replacement steel canister filters at autozone. Not sure what car it was for, but it's 1" diameter and is sealed so you can't see the filter. I put it right after the fuel pump and it is hidden underneath the PS pump. With the plastic screen type that i had on my car, there would be some larger stuff in the filter but when i removed the upper plate on my edelbrock carb i saw all kinds of crap in the fuel bowls. This is quite likely your problem and would be a good time for a tear down and rebuild the carb. Good way to learn a bit more about them too if you aren't familiar with the internals of a carb.

 

[palerider94]

Thanks - Roofusbooth - Just so that I'm clear - You mentioned no rubber line at all between the carb and filter - correct?

That means I will need to rig a hard line into my holley. Also, you mentioned currently clean carb out - I've taken it off about 20 times now so now a problem but do I need to dismantle to clean bowls as you mentioned?
I'm hoping I don't need to do a rebuild - just put carb on yesterday. But I definitely want to lick this problem it has become very aggravating.

 

[BIG-MAC]

You might also check the power valve....when the diaphragm fails they will flood the engine.

 

[rufusbooth]

If you do have rubber line make sure that you replace it with new Fuel approved lines. The old lines can flake off pieces of rubber and get lodged into the needle and seat. The goal here is to get everything after the new filter spotless and absolutely free of debris. As far a rebuilding the carb I doubt that will be necessary unless you are having drivability issues beyond the engine flooding. I recommend that you clean out the float bowls to make sure that you get any debris that may have past the needle and seat out before it causes any issues in the inner working of the carburetor.

When it comes to carbs…cleanliness is paramount.


BIG-MAC also has a point about checking the power valve since you will have the bowls off it is easy to do. But I doubt that is your problem as you do have significant periods of time when the engine is running properly.

I hope that helps and resolves your issues. Let us know how it goes.

Cheers,

Rufus

 

[palerider94]

Just bought a new line from pump to carb and got a fuel filter with paper element. Will pull carb out and clean bowls with carb cleaner. Do plan on replacing all lines but wanted to wait till I replaced my floor pans first. Hopefully this will hold me over - sounds like wha the problem could be. Especially since I put some fuel cleaner in befoe all this started to happen. Appreciate your help and will post how things turn out. thanks

 

[palerider94]

I've decided to replace all my lines - old ones have rubber patches in place. Only question is should I run 2 filters on right after the tank and one before the carb?

 

[D.Hearne]

You can run two filters, but put only one between the tank and pump ( mechanical only, electrics, you can add more) I run rubber fuel lines on many of my cars, nothing wrong with it, long as it's new. Or the car doesn't catch fire, in which case, the rubber doesn't add much to the flames. Metal lines are a pain to install, so I just forego them, yea I take a risk, but it's mine. I also agree that you need to clean out the carb including the needle/seat assemblys, it doesn't take much to get them stuck open. This is the primary reason to run a filter or two with a Holley. I've got three on my V8 ranger.

 

[palerider94]

Thanks - just ordered new stainless lines, fuel pump, tank sending unit, and an inline Holley filter from NPD. Already has a fairly new tank. Was planning also to put another filter right at the tank - clear paper element type. Took off the carb yesterday took off the float bowls and sprayed inside with carb cleaner. Plan on putting everything together this weekend. Maybe overkill but had old lines and wnat to make sure that at least I won't have any more problems with feul delivery. LIke to eventually get to the oil leaks. Thanks