my slick is sick any ideas

crewzinforabrewzin · Post by **crewzinforabrewzin** » October 4, 2008, 9:58 pm

my slick started running like crap, during about a 2-3 week period. been a bit harder to start. i have lost all power. a good runnin 300ci engine up till now all of a sudden will barely do 35-40mph, and it takes almost 2 miles of straight and flat road to get her going that fast. my muffler is rusted out and shot so i cut evry thing off from my muffler back.I bought a new muffler however havnt got around to putting it on yet. I have replaced the sparkplugs(I did gap them), however there were 2 diffrent plugs it called for. not knowing wich i had in my engine i guessed and bought the medium duty plugs. ended up having the heavy duty plugs that were hotter. there wasnt much left of them so i went ahead and installed the medium duty plugs. also new plug wires, cap,distributer button, and points. still not wanting to run i replaced the fuel pump and filter, and still not runing good at all. the engine when idling sounds smooth and strong with no knocks or odd sounds. the carb is an old single barrel holly, for the 2 years i have been driving my slick i have thought the carb was worn out, i think i have elimanated and replaced evrything else that could be the problem, however i dont know much about carbs, and hate messing with it, afraid of messing up the adjustments on it. does this sound like a carb issue? i have checked the price on rebuild kits and know people that can hep me rebuild it, but i dont want to spend the money and time if its not my problem. am i correct in thinking that the medium duty plugs instead of the heavy duty plugs and lack of muffler wouldnt be causing my truck to run this poorly? also i have replaced the airfilter and blew compressed air through my fuel lines so there shouldnt be any crud blocking them.any thoughts where my problem is

slick4x4 · Post by **slick4x4** » October 4, 2008, 10:23 pm

you probably already did this , but i never saw where you checked the timing. i would do this first.

Thunderboy · Post by **Thunderboy** » October 4, 2008, 10:48 pm

After you check ignition base timing, check fuel pressure and volume. At least 3 psi (5 psi would be typical), and for volume, 1/2 pint in 15 seconds, while cranking the engine.

I have no idea why anyone would still run ignition points in anything. I suggest either a Duraspark conversion (instructions found i several sites on Internet -Google it- or Pertronix. Both are easy and very reliable.

crewzinforabrewzin · Post by **crewzinforabrewzin** » October 4, 2008, 11:27 pm

how would i go about finding fuel pressure and volume? can i disconect fuel line from pump to carb and just run it into a bottle while cranking engine to find volume?

Thunderboy · Post by **Thunderboy** » October 5, 2008, 12:00 am

For volume, yes, Crewz. Add a hose that extends to the ground, so gasoline won't splash anywhere but into a container.

If you have a vacuum gauge, you can check for a plugged exhaust, and get some info about the engine condition. If you attach it to a vacuum port in the middle of the engine (near and under the carb), you should have 17 -22 inches of mercury (in. Hg) at idle. Then hold throttle to about 2500 rpm for about 30 seconds. When rpm steadies, vacuum should hold steady at or above idle vacuum. If vacuum decreases within a few seconds, you have a restriction in the exhaust.

Many vacuum gauges will also read up to about 5 -10psi, so you could check fuel pressure on a carbureted engine with a mechanical fuel pump. A Haynes or Chilton manual at a parts store would show you this, as would many sites on the Internet. Good luck!

Drew

blackagatha · Post by **blackagatha** » October 5, 2008, 12:20 am

dude, at this point in the investigation, the Carb is the VERY NEXT THING I would look at.... If not even sooner than now.

It sounds very similar to the day my dad's Holley 4Barrel on his 390 got plugged up with sediment. He had the pedal to the floor and it was hicthcing and bucking and wouldnt even make 25 to get home from the end of the street.

He opened it up and found both floatbowls almost Completely Full of crap.

Rebuild the Carb. It is NOT terribly complicated. Just make sure all the parts are accounted for when you put it back together, and dont over tighten the screws. Adjustments are minimal and easy.

johnny · Post by **johnny** » October 5, 2008, 1:20 am

does it have a miss? if so find the dead cylinder an easy way i do that is get a test light pull the bulb get a wire w/ clips clip one to the test light probe the other to ground with motor running (be better in gear with someone on brake if an auto.) prob each wire at cap and listen if each cylinder dies when you probe it that way you ground out each cylinder and wont get shocked and also i agree with agee check the carb out, if its not the carb do a compression check hopefully all cylinders are within 10-20 pounds of each other, also hows the oil look if milky maybe blown head gasket if you blew in the fuel line you probably stirred up a lot of sediment in the tank check you filter and fuel line could be collapsed just my

John

DCarr · Post by **DCarr** » October 5, 2008, 2:09 am

If you have a heat riser valve in the exhaust pipe (flapper just under the manifold) , make sure its open , not stuck shut or partially open . Just a thought.

Thunderboy · Post by **Thunderboy** » October 5, 2008, 7:39 am

Even easier, Johnny, when you use a test light for checking for cylinder balance, you don't need to take out the bulb. It is a few thousand volts, but it isn't for enough time for an incandescent bulb to burn out. I do this all the time, on many different test lights, w/out hurting them at all.

I re-read the intial post, Crewz, and saw that you already replaced the fuel pump. I agree with blackagatha, seems like a lack of fuel, likely due to a restriction caused by dirt in the carburetor.

If you can build a cheap model airplane, you can rebuild a carburetor. Way easier than you think. Dissassemble, clean, use compressed air to clean out all the passageways, set float level, replace all soft parts, don't overtighten the fasteners, and reinstall. Reset idle speed and mixture.

Slick Fan · Post by **Slick Fan** » October 5, 2008, 9:56 am

I've gotta agree, it sounds like it could be carb problems.
The upside is that the carb on that truck is one of the most basic things made...just like the rest of the truck, no frills.

A carb kit will come with instructions & some pictures, so you can't get too lost.

Do what I sometimes do, when I'm digging into some unfamiliar automotive territory...take the carb off & clear off a large spot on your work bench. Begin with the carb facing you & take it apart with it still facing you. As you remove things, place them on the bench in the same sequence & position that you removed them. If you need to, clean one part at a time, then put the clean part back in it's spot on the bench & move to the next part.
Clean the bare carb body & all metal pieces liberally with carb cleaner & compressed air...don't shoot yourself in the eye, it hurts.

After it's all clean & dry, reassemble the parts, double check the float level with the kit instructions, screw it back together & slap it on the engine. Make your idle & fuel mixture adjustments & you should be good to go.

Fanatic · Post by **Fanatic** » October 5, 2008, 12:05 pm

Check that the vacuum advance is working on the distributor!

ICEMAN6166 · Post by **ICEMAN6166** » October 5, 2008, 2:02 pm

Thunderboy wrote: I have no idea why anyone would still run ignition points in anything. I suggest either a Duraspark conversion (instructions found i several sites on Internet -Google it- or Pertronix. Both are easy and very reliable.

because i live out in the middle of nowhere and points are easily changed out, where broken electronics leave you stranded.

Thunderboy · Post by **Thunderboy** » October 5, 2008, 9:07 pm

Fair enough, Iceman. Points are easy to change. But they also wear, changing dwell and ignition timing. I think they fall out of adjustment pretty easily, and may cause the driveability issues described by cruze above. It is kinda nice to not look askance at the distributor every time the engine bucks, stumbles or gets poor fuel economy.

In a Duraspark distributor, there is only a magnetic pickup that indicate position to the module. You likely keep a spare set of points and maybe a condenser in the truck. I do keep a spare module handy, too (but I have never needed to replace it so far). To generalize, parts that don't touch each other don't cause problems as often.

My $.02

Drew

ras4434 · Post by **ras4434** » October 6, 2008, 10:23 pm

crewzin: I had a 300 for 25 years and had that problem twice and both times it was the carb. Let em guess,,,,is it an Autolite one barrel? Rebuild kit is cheap and fairly easy. I just got rid of the last two carbs I had but if you want to just change out the carb send me a PM and I will check with a friend who has one on a running 65 that he might part with. Good luck.................Ross

BAMAFORD · Post by **BAMAFORD** » October 7, 2008, 5:18 pm

Yah Cruz, if you have the one barrel autolite it is very easy to rebuit and the rebuilt kit is cheap. I've had to do mine twice in the last several years. Got the rebuit kit from car quest - about 20 bucks or so.

blackagatha · Post by **blackagatha** » October 8, 2008, 1:59 pm

autolite 1 barrel is easy? ggod! the Holley 1 barrel was the most over complicated POS I ever had to deal with!

DCarr · Post by **DCarr** » October 8, 2008, 10:08 pm

OK ,Crewz , you gotta let us know who guessed correctly. We're dying from the suspense. Is there a prize involved?

Slick Fan · Post by **Slick Fan** » October 9, 2008, 10:17 am

Yeah, what's the prize?

jakdad · Post by **jakdad** » October 9, 2008, 10:24 am

FANATIC said it. Try another vacuum advance cannister.