Engine and Transmission Tech

I hope your Holidays were great!!

Need a lil help guys,

Been rackin my brain tryin to get this thing to run right. The carb is leakin from the pass side main venturi. but not from the jet. It's wierd.

So this, i think is causing me to foul plugs, and drop cylinders....its killin me.... and drainin my pocket to boot.

I've changed the plug wires, rotor and cap on the distributer. Found my Coil has too much resistance so thats the next step.

AND... I've been told recently that a 600cfm carb is too much for the motor.

PS... I just want it to run smooth

Thanks guys! and Happy New Year

I've taken the liberty of moving this thread to the "engine" section where it will likely draw more replies.

I can comment on two issues:

(1) an Edelbrock 600 is certainly not too big for a 289cid motor. Maybe it's bigger than ideal, but that carb has been used quite successfully on smaller engines including quite a lot of the 215cid engines seen on this website. It's versatile.

(2) have you bought and installed a rebuild kit yet? I learned (again) this year that trying to repair a carb without replacing all the disposable parts is a mistake.

Thank you Sir!

I think that will be a the next step in the process involving the carb... rebuilding it... again.
Just blew it out with an air compressor, tried switching the gaskets on the venturies, and now both sides leak... bad. but it doesnt happen ALL the time, only like 50% of the time. Do you think the Fuel pressure is too high? How can I gauge that? should I put a pressure regulator on it? I was hoping to stay away from as many electronics as possible?

And, New issue... do I need to have a balast resistor in line with the coil... how necessary is this?


Totally lost now....

OH... and now it runs worse.....

Total Fail...

What fuel pump are you using? Most of us use electric fuel pump models that don't produce enough pressure to disturb our carbs. If your pump and carb ever worked well together, you're probably still okay. You (or a shop) could put a pressure gauge on the line just to check. That might be cheaper than a pressure regulator. My intuition is that your problem is probably in the carb anyway. The good news is that the popular regulators (Holley, etc.) are strictly mechanical.

What coil are you using? It's usually a mistake to work on ignition and carb at the same time because symptoms can get confused. Whether or not you need a ballast resistor depends whether or not a resistor was built into your coil. (As an aside, some car models including MGB were built with a special "resistance wire" in the wiring loom - so on a stock MGB a ballast resistor would be redundant.)

Don't give up. You're just a few hours of shop time away from Total Success.

thanks for the boost, i really appreciate it.

it's a hi flo mech fuel pump for the sbf 289, as I understand, it puts out 6.5-8 psi. which I'm afraid may be too much. I was thinking about installing a fuel pressure guage in the line... Would a simple guage like that be reliable?

I just installed a MSD Blaster (ignition coil).

We dont' seem to be having any issue with getting spark at the plugs, so I'm not too concerned with this yet, but we are having a problem with cylinders not firing. When I pull a plug out that seems to not be firing, it was black and smelled slightly of fuel, but that same plug fires when sitting on top of the motor and I turn it over

Tell us some more about the symptoms...

Did the carb ever work right?

How new or old is it?

When you say it's leaking fuel from the venturies, can you clarify where it's coming from? Is it coming from the circular part that hangs out over the bore?

When you said it had been rebuilt, how long ago and was it shortly after that when it started dribbling fuel.

My guess is there's either some debris keeping the needle(s) from seating or your floats need to be adjusted. Do you have the Edelbrock manual showing how to adjust the floats?

Carb symptoms.... hmmmm...

Leaking at both venturies now.... pulled them off checked the gaskets they are fine (or so they "seem")

Carb is old enough to be a doorstop as far as I know. I think... its always been on there (about 15 yrs)
I rebuilt it about three years ago, this is what brought on the rebuild of the motor. I rebuilt the carb and it made a world of difference back then. It has sat for just as long tho. Today I went through it, blew out the garbage it seems to flow better, but still overflowing with fuel. which is why I think the fuel pressure may be "part" of the problem. It does seem to be coming from the "circular part that hangs out" (isn't that the booster?)

I think thats about it

Quote:

it's a hi flo mech fuel pump for the sbf 289, as I understand, it puts out 6.5-8 psi. which I'm afraid may be too much.

Yep., 6.5psi is max for an Edelbrock. Check the float level while you are at it. Also, make sure the the float doesn't have gas inside it.

As a corollary to Carl's comments - I've found that 4 to 4-1/2 psi is plenty for an Edelbrock and anything above 6.5 will flood.

Agree on the pressures, but seems odd that a combination of parts that'd be overflowing on a regular basis would have gone 15 yrs. I'd go ahead and put a fuel pressure gauge on it but am still thinking the floats need adjusting (or replacing if they've filled with fuel) or there's trash, varnish, etc keeping the needles from seating.

I kinda thought so, but others have been telling me it shouldnt matter. so i didn't pay it any mind.....

back to the part store....

I will follow up tomorrow with any news.

thanks again!

OK, So... i'm a moron apparently...

Th plug wires were attached to the distributor in the wrong order, its a wonder it ran at all...

Burned up the coil from not using a resistor, so that answered the question of "is this necessary?"
pickin up a new coil today and a resistor. back to it on saturday night or sunday.

Got a fuel pressure regulator, this seems to help a lot with the overflowing of the carb, won't know for sure until we get it running, but the leaking at the boosters seems to have subsided, for now.

Stay Tuned, more to come!

Alright!!!

We got her turned over and runnin smooth, idle is a little high, but she lives!

The pressure regulator seems to work great set at 4 psi, so we'll leave it there for now.

The ignition problems were stemming from bad points adjustment. Small issue there though... after I set the points to the position, the car would run for a few minutes and then the points would fall away again. Gonna replace the innards of the distributor this week and go from there.

But we got the firing order correct and after reading and trying a number of different setups with tdc, rotor placement and distibutor alignment we finally got it to purr, and boy did she!!! What a feeling, I actually got some sleep last night... lol.

So, we'll get her tuned up and I'll post a link to a video of her runnin, (if thats ok with the admins) (youtube ok?) and I can show some other small things that were done.

Thanks for all the responses and help.



Edited 1 time(s). Last edit at 01/07/2013 08:44AM by mtnrek@yahoo.com.

Very cool! I'll look forward to the video.

Great news & thanks for the update! Looking worward to hearing and seeing it running.

What are points ? Do people still use those ?

LOL, thats funny... but I do see why the change is almost necessary...

I replaced the points and melted them, so I've decided to remove the points and replace them with an electronic system that replaces the points and condensor components. Anyone have any experience with this?

Pertronix works fine as point replacement.

+1

I used run points. They would pit quite fast (I need more ballast resistance). Switched to Pertronix many years ago & stored the points in the trunk just in case.