Fuel filter clog leads to carburator demise

[The_Handier_Man1]

From: ClydesdaleKevin  (Original Message)
Sent: 10/12/2005 1:06 AM

We are stranded in Kentucky, on the way to Texas!

Let me start at the beginning:

When I first bought the rig (1972), the fuel filters were clean, and the tanks said "Good, '89".  I've run it over 2000 miles, and haven't had any problems, until relatively recently.

I bought two new gas caps, and they are the "vented" style.  I even bought them at NAPA, so they should have been good...but one of them started vapor-locking on me, and sometimes I'd have to stop and switch gas caps on whatever tank was full.  This was few and far between, and for a while all seemed good.

We've driven over 600 miles in the last couple of days, and the gas cap vapor lock started to get critical.  Instead of just one cap, it became both.  By vapor lock, I mean that when I pulled over because of fuel starvation, both caps would HISSSSSSSSS in air intake, meaning of course that they weren't venting!  Ah ha!  No problem, says I.  I poke at the vents with a screwdriver until they are both venting, and for about a hundred miles, all was well.

Same symptoms started...fuel starvation.  I could idle with no problem, but try to open it up?  Bog down and even stall!

I thought back to the fuel filter threads, and checked them.  They both seemed pretty grungie!  Very clogged.  Well...I didn't have a spare, so I bypassed them with fuel hose.  I figured it was only about an hour to a WalMart, and I could pick up new filters there.

Problem solved for about 12 miles...now it was worse!  Or better....just different!

At first, it ran great, just as usual.  Then it started to chug in the midrange.  Then I could only keep it running by having it full trottle with both barrels kicked in!  It would idle just fine, and wide open it would run OK, but without full power...it seemed like just the two secondary barrels were kicking in.

SO, thinks I...rust particles got into the carb, and I clogged my running mid range circuit!  That's the symptoms it had.

Solution?  I made it to the Walmart, and as my luck seems to have it, there was an Advanced Auto across the street.  I bought 2 new fuel filters, and 2 cans of carb cleaner.  I replaced the filters, and then removed the carb.

I took the float bowls off and was lucky the gaskets didn't tear.

Without messing with ANY adjustments, I cleaned out the float bowls, the float needle valves, and every jet and port in on the carb.  I was careful, and reassembled it just like I took it apart.

Reinstall went smoothly, and I was ready to start it.

Nada.  She started for a minute, and then died.  Then, to my horror, I noticed that gasoline was GUSHING from the upward-pointing pipe on top of the carb!  Its a Holly 4 bbl, and I'm not sure what that upwards-pointing pipe is for (its inline with the bolt that holds the aircleaner down), but I KNOW that its not supposed to SHOOT gasoline straight up and all over the inside of the aircleaner!

And to make things worse?  The fuel mixture was SO rich, AND I DIDN'T MESS WITH ANY ADJUSTMENTS, that I had a mini-fire!  My exhaust manifold on the drivers side is missing a bolt where it bolts to the "header" head pipe...and whenever I tried to start it, flames were shooting out the bolt hole!  Very scary!

So, what should I do?

The Advanced Auto actually has a Holly 4bbl carb, 600 cfm, that looks to be an exact replacement, for 260 bucks.  The configuration, even for the linkage, appears to be exact.  Should I go for the new Holly?  Was my carb just on its way out, and I accelerated its demise by running it without fuel filters?

Also, about the fuel pump:  Its a mechanical on my 413.  It looked new when I bought the Ark, so I never replaced it.  Is it supposed to deliver the fuel in "pumps"?  I assume it should, and that it won't be a steady stream (that's what the float bowls are for), but should it deliver fuel in pulses like mine is doing?

One last question:  Anyone have the size and threads of an exhaust bolt handy?  That was where the fire was coming from, and I'd like to seal it up.

Thanks for being patient with such a long post, and I hope some night-owls read this before I buy the new carb tomorrow!

Kev



From: denison
Sent: 10/12/2005 8:02 AM

That vertical tube on your Holley carb is the vent for the float bowl. If fuel is squirting out there, you have a float bowl needle that isnt closing or a float that is stuck on the side of the float chamber, or something. This would let fuel continue to pour into the float bowl, overfilling it, making the mixture way rich, and eventually pumping fuel up/out from that vent tube.
Yes, the fuel gets delivered in spurts, one per each camshaft rotation.
The intake ports on a 413 should be square-bore, unlike the 440 intake manifolds.
I recall the exhaust studs being 3/-18 into the head also.
The carburetor would only have been clogged by the crud that came through the line, no permanent damage. It can easily be rebuilt, but you have to be careful to get all of the dirt out. I have done it myself twice, since with the vehicle sitting for months at a time, the gaskets for the float bowl last less than a decade before they leak. The jet assemblies unscrew on mine, then you have to try to get them screwed back in to just the same ‘depth’. This controls the fuel level in the float bowl. The rebuild kits list the dimensions for the float to lid spacing. The rebuild kits should also come with a new jet assembly, since I don’t know if you can effectively open up a Holley needle and seat assembly and put it back together.

I had the same thing happen to my Holley when the diaphram in the original aged fuel pump began to shed rubber chunks.
If you decide to put on a different carb, make sure you have the correct throttle linkage parts.

Along with the 2 new fuel filters, you still need to carry extra ones. The new ones could clog up in 50 miles of rough pavement, or they might last 5000 miles. When you have a clogged fuel filter and no extras, whacking the side of the filter will sometimes let you get a few more miles down the road; by shaking some of the crud off the pleats of the matrix.
The difference between a 600 cfm or a 625 or 650 cfm carburetor isnt going to make much difference on a slow turning engine. I doubt you would be able to tell any difference, even at full throttle.
I don’t think Holleys are troublesome. Your 413 probably originally came with a Carter 4 barrell carb.



From: denison
Sent: 10/12/2005 9:39 AM

If you get a chance to read this before you start up again - there could be some sediment/rust that had gotten into the fuel system 'downstream' from your fuel filters, in the fuel pump and the lines going up to the carb, when you bypassed the fuel filters. It would be good to clean this stuff out.
When I did this, I ran a length of rubber hose from the end of the fuel line where it would connect to the carb, down to a gallon milk jug instead. Then I dribbled clean fuel into the float bowl vent, so the engine would start/run briefly. I started it and let the the fuel pump squirt about a quart of fuel into the gallon jug. Then I shut off the motor and connected the (hopefully cleaned out) fuel line to the carb.
You could do almost as well by cranking the engine over and let the fuel spill out to the side. If you catch the fuel in a clear container, you can see whether it is clean or not.

When you go to start up with a new and empty carb on the engine, if its a Holley you can pour a few teaspoons of fuel down that vertical float bowl vent pipe - so the engine will start up without cranking a long time. Thats what I always do if my winny has been sitting idle longer than 2 or 3 weeks.



From: ClydesdaleKevin
Sent: 10/12/2005 9:29 PM

Thanks Dave and Tom, and for taking the time to email me with your numbers and whatnot.

Problem solved!

They didn't have the rebuild kit, so I bought the Holley.  Dave mentioned the stock carb was probably a Carter, so the one in the Ark must have been an upgrade at some point in its past.

Anyhow, the Holley, model number 4160C, was an almost exact fit!  I had to drill one linkage hole slightly bigger for my old linkage (the part that the throttle cable slips over, etc.).  I also had to tap the OEM supports that are bolted to the manifold slightly towards the passenger side with a mallet to line everything up properly (the distance was perfect, but the linkage on the new carb was about an inch less wide than the old carb...tapping over the supports lined up the throttle cable and the tranny shift linkage thingy).

The replacement went so quick, we were on the road again by noon!  We drove until 7pm, and are overnighting at a Love's Travel Stop just outside of Memphis!  So, here's the scoop on the performance of the new carb:

I don't know what the CFM on the old carb was, but this one has more than adequate power!  I can pull hills a lot easier now, and maintain 55mph on a lot more hills than before.

There don't seem to be any dead spots in the acceleration at all, and while she's still not a race car, she wants to go faster than 55mph, so I have to concentrate on the pitch of the bias tires, since I can't even hear the rpms of the engine anymore...lol.

At idle, its amazing!  So THIS is how its supposed to run!  Idle is a lot lower than the old carb, and it doesn't search irregulary like the old carb...it idles smooth as silk, and I can't even tell if its running anymore except for the guages at stop lights!

And here's the best part!  My average highway gpm went up from 9...to 11!!!  This carb will pay for itself soon!

I'm going to rebuild the old carb, and keep it for a spare.

I forgot all about the exhaust bolt...ah well...I'll get around to it eventually.

Thanks again, guys!

Kev



From: denison
Sent: 10/13/2005 6:58 AM

Delighted to hear you are ‘travelin’ again. The replacement of the original Carter carb. with the one you removed yesterday probably wasn’t an upgrade, but done to get the engine running again â€" in circumstances like you found yourself in. There is No Way the original (or any) carburetor would have lasted this long without either having been rebuilt more than once â€" or ceasing to work right. Can you give us the part number that you bought? If your mileage is that improved, I need to buy one of those myself!
And your old carb should have run just as well as the new one I believe â€" if it had been recently rebuilt, etc.



From: ClydesdaleKevin
Sent: 10/13/2005 8:52 PM

Gas mileage is varying, but still much better than before.  In the steep long hills between Nashville and Memphis on I-40, I was getting 9 mpg.  Once it flattened out in western TN and Arkansas, I got as good as 12 mpg.  I'm on RT 59 in Texas right now, overnighting in a town called Marshall, heading south.  I filled up before I hit 59, so I'm not sure of the mileage on this stretch of the road yet...lots of stop lights, driveways, and whatnot.  I do know that I haven't switched tanks yet, and I've gone 179 miles since I filled up (both tanks are 24 galloners).  I'll keep you posted, Dave.

Oh yeah, the carb is the Holley "4160C UNIVERSAL 600 POLISHED."  It was 268 bucks at Advanced Auto Parts.  The part number is 0-80457S.  I'm sure unpolished would be cheaper and work just as well, but this was the only one they had in stock.  Edlebrocks were MUCH more expensive!  And you'd still have to buy the adapter plate!

Now that the carb situation is in hand, and I have spare fuel filters on board, I'm noticing some other quirks that are either starting, or I simply didn't notice before with the rougher running carb.  When the engine heats up to a water temp of about 180 degrees and stays there for an hour or so, it seems that my engine is missing sometimes, especially when I accelerate up hill.  I suspect the coil is on its way out, and generates less spark than it should when hot.  Also, I haven't adjusted or inspected the points in about 2000 miles.  And also, I haven't inspected the spark plugs since the carb starting acting up and running rich.  Any ideas?  I'm guessing I need to give her a full tune up when I get to Plantersville, TX, since I'll only be working weekends, and I'll be there until December...new plugs, coil, wires, cap, rotor, points, condensor, etc.  Any recommendations on brand names for these items?  Should I go for a high performance coil, etc?  Also, and I say this sheepishly since I was on the bandwagon defending points...how much do electronic ignition systems run, whats a good brand, and are they worth the money?

Thanks!

Kev



From: ClydesdaleKevin
Sent: 10/13/2005 8:55 PM

Did I mention WE MADE IT TO TEXAS?  We're only 220 miles from the faire, and will be there tomorrow, Friday, by noon!  Wooo hooooo!

Kev



From: ClydesdaleKevin
Sent: 10/13/2005 10:26 PM

Hey Dave,

I was thumbing through the 72 service manual, and it seems that the Holley I had WAS the original!  Its the Holley R-4399-A, and came as the standard carb for the 413-1 engine in 71 and 72.  Not the Carter.

Kev



From: ClydesdaleKevin
Sent: 10/17/2005 7:51 PM

The Chysler parts numbers for the 413 built in '71 are "2875 986" for the "Chrysler built" distributor.  In 72, it went to the "3656 366", with OUT electronic ignition (points).  In 72, there WAS an electronic ignition option, and the dist. number was "3656 686."

From my VIN numbers, even though my coach is a '72, it appears that my engine/chassis is a 71.  AND it had points, not electronic ignition.

So, my assumption, reasonably, is that the actual part number is "2875 986".

In either case, do you know how much it would cost me to switch to "E/I", a reliable name brand, and where to get the parts?

Kev



From: cooneytunes
Sent: 10/17/2005 8:00 PM

Kev ....NAPA has the electronic ignition module for around 19 bucks...I'll see if I can get the numbers in a couple of days.....I was going to get one (for a spare) and put it in the box with my spare ballest resistor for those "Just in case moments, or better to have and not need, than need and not have"....

Timmy



From: ClydesdaleKevin
Sent: 10/17/2005 8:30 PM

Thanks Timmy!  Are you saying I only need a module to replace the points, and not an entire distibutor assembly?

Kev



From: denison
Sent: 10/19/2005 7:15 AM

Another way to identify: With the distributor cap off, crank the engine to see which way the rotor/distributor shaft turns. If it turns Counter-Clockwise as the engine is cranking, you have a timing chain turning the camshaft. If it turns Clock-wise, you have an early enough 413-1 to have the gear driven camshaft.
There might still be an aluminum tag on the distributor body with a part number, but I never had any luck finding that same number in the parts catalog or at a parts place. 



From: ClydesdaleKevin
Sent: 10/20/2005 3:28 PM

Thanks Dave!

I'll snap a picture of it either today or tomorrow, and post it.

As far as where the dist. advance is, that's easy, since I just replaced "all" the vacuum lines when I replaced the carb.

The vacumm advance modulator is on the rear of the distributor, almost facing the carberator actually.  So, it faces the rear of the engine/vehicle.  The distributor itself is canted at almost a 45 degree angle towards the passengers side, and the distributor itself is located on the right side of the engine, forward of the carb, in the front right (passenger side) corner of the engine.

I actually hope it is the earlier timing GEAR model.  I fondly remember my old VW aircooled motors, and the brilliance of a design that doesn't have the weakness of timing chains and belts. 

Like I said, I'll snap a picture of it for you, but hopefully the description I gave will provide some decent clues.

Kev 



From: denison
Sent: 10/20/2005 4:37 PM

Sorry Kevin; Your description doesnt tell me enough to know if the advance diaphram would pull the swash plate clockwise with higher vacuum ( meaning a spark retard for a distributor driven by a chain) or if the little arm from the diaphram in the vacuum advance unit would pull the swash plate counter-clockwise -(which would mean the distributor was driven by a camshaft turned by a gear. A closeup photo would tell, or watching for the direction that the rotor turns when you crank the starter with the dist. cap off.
As far as the timing chain wearing out, do not to worry about that. Timing chains wear out faster if they are long, like the timing chain on a large overhead camshaft engine, like the Jaguar and Mercedes OHC motors of yesteryear. (I have had timing chains get loose and growly on both my Jag at 100k miles, and an MB 180 that had 350k miles on the engine! The chain on our mopar V8s is very short.
They also wear out faster if the engine speed is changing often and dramatically; Such as an urban delivery truck would see. I believe the worst wear occurs when the crankshaft is abruptly dropping in speed, such as when a teen age guy pops the clutch to spin the wheels on his Pontiac Bonneville, Plymouth Fury, or Galaxy 500XL.
Since motorhome engines operate at relatively steady speeds, and relatively slow rpm's at that, I expect a 413 timing chain would last well past 300k miles.



From: denison
Sent: 10/20/2005 4:41 PM

Correction, where I said "spark retard" I should have said "spark advance'. With higher vacuum the mixture has to be ignited sooner in the compression stroke, to maximize the energy of the burning gases pushing down on the pistons during the power stroke. 



From: ClydesdaleKevin
Sent: 10/20/2005 5:17 PM

Ah ha!

I found some pics of the distributor on page 5 of my album, under the heading "heater hoses", and another not-so-close-up on page 11, where I'm riding with a rope on the throttle...lol.

Kev



From: denison
Sent: 10/20/2005 10:06 PM

Your vacuum advance connects to the dist. in the direction for a counter-clockwise turning distributor. Also means your 413 has the double-roller chain turning your camshaft.



From: ClydesdaleKevin
Sent: 10/24/2005 12:08 AM

Thanks Dave!  I wish it was a timing gear, but if wishes were horses, the Ark would fly!...lol.

BeenRealBusyAtTheFaire Kev



From: Slantsixness
Sent: 1/31/2006 7:50 AM

Kev,
Coil is probably ok, but I think you might try a new set of points.

All Chryslers are prone to medium to high RPM ignition misses (this usually happens when you're maintaining highway speeds, and you can feel this "flutter"), but this is primarily "pre-ignition detonation". The cure for it is electonic ignition, and higher grade fuel, but short of buying 93 octane fuel that you can't afford, keeping the points adjusted every 2 or 3 thousand miles will improve it, and your gas mileage.

Converting to Electronic ignition would be your best bet, and pretty cheap to do It solves most of the "at speed" ignition misses.

Now if you were going for "originality" obviously you'd have to stay with points, but to me, Points are archaic and require periodic maintenance, where electronic ignition requires almost no maintenance in 100,000 miles of driving.

I can fish you out some part numbers and stuff you'll need, but we would have to define exactly which 413 you have, since there are two different distributors due to the different timing chain, or gears. the distributor part # and a picture of it would make it easy.

Tom



From: Slantsixness

Kev,

You need a holley tuning book, you can get one at Advanced Auto...in the service manual isle...

but,
I'd get a replacement carb so you can get back on the road quickly. I'm not so sure the 600 cfm carb is going to be the same, you may have a 650cfm or even a 625... with the 413 you may need that extra flow. there are ID numbers on your holley, check it out to be sure.

it actually sounds like you have a stuck float  (in the front bowl) or it got misadjusted when you cleaned it out, or was put back together improperly. Almost any "speed shop" should have a gasket set for a holley 4 barrel.

My only other recommendation is to get rid of the troublesome Holley altogether and opt for the aftermarket Edelbrock 650cfm square bore carb, or a good old trusty thermoquad from a junkyard or rebuilt at a parts store (but you'll get stuck with the core charge). But I'm not sure whether your intake is spreadbore or squarebore, original or a perfomance aftermarket. Thing here is, is there an aluminum spreadbore adaptor plate under the holley? and is the intake carb hole square, or spread out in the secondaries, which would accomodate the thermoquad? Is the intake aftermarket (aluminum) or cast (magnet sticks to it)

If you have a squrebore manifold, (or if you have the square bore adaptor plate for the holley):
The Edelbrock carbs (1400 series) are actually Carter AFB carbs, Tried and true reliable performers, and are available at most auto parts stores. I think they're even cheaper than the Holley's, to boot.

the exhaust bolts are 3/8-18's if it was a bolt, exhaust studs were 3/8-18 into the block, and 3/8-20 (fine thread) on the nut end. I think this is right, and from memory, so to be sure, just take one of the other ones out and take it with you to the parts store!

Tom