small problem with the holley 350 on my slant 6

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Mopar King

Mopar King

Beginner / Need of Help
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As the title saids - I have a slightly small problem with my holley 350 carburetor #2300 on my stock slant six. I was test driving the car when all of a sudden it started to shake like crazy and was losing power until... it actually shutoff. I was close to home and there was no one around so i wasn't blocking traffic. It was driving fine a few mintues ago and then its started to act up. tried starting it but now it refuses to start and sometimes shoots out of the carb when too much gas is pressed. now the car is parked until i can find out why it doesn't want to start.

Im not sure if this is related but when i tested drived the car, the car seems slow and not as responsive (perky) when in stop and go traffic.





  • I did cleaned and check my spark plugs (took gasket rings off)
  • gas is going into the carb, shoots good shots of gas,
  • gas-line is checked and freeflowing
  • checked float level on carb's side and its at the right amount,
  • played with needles by closing them / opening them
  • checked timing three times and have it at 5 degress btdc
  • checked all spark plug wires and there number rotation (summit racing 7mm I believe)
since its raining now i have to wait until tomorrow so i can trouble-shoot this some more maybe play with the timing. if i miss any detail or if you have any additional test that i have forgotten let me know and I'll try them thanks
 
Sounds like it got some dirt in the carb.
 
I was thinking of that R.RatRod - i check inside the carbs holes and open her to WOT so i can see the manifold floor inside and don't see anything. I was thinking of taking the carb off completely to check but as a last opition if Im stumped. :prayer:

cjh forgot to add, I converted it to an electric ignition system
 
Was it raining or had you driven in some deep puddles before this? Could be moisture in the distributor, shorting the sparks if that is the case. With the info you provided on the carb having gas, etc, then it seems more likely ignition related since it won't even fire.

Your initial post has a missing word; you wrote: "sometimes shoots out of the carb when too much gas is pressed"

Shoots what out of the carb? Fire? Smoke? Party favors? Bullets?
 
For when you get it started, food for thought.

Does it have the float bowl vent baffle installed? Many people don't know than an inline engine produces much different harmonics than a V8 and that can lead to fuel problems in the carburetor. If the float bowl vent baffle is not installed, fuel can be forced into the vent and actually out the top and right into the primaries. This is why a lot of times you see Webers on inline engines. They are actually designed for inline engines, where that Holley 350 was not. Even with the float bowl vent, they can have peculiar running problems that cannot be explained any other way.

Lastly, do not forget to run the THICK (about 1/4") insulating gasket under the carburetor. The intake and carburetor sit right on top of the exhaust manifold and can percolate the fuel pretty easily. It's a common problem.
 
Get a cheap in-line spark tester at Harbor Freight and verify you are getting good spark. If truly the carb, I would suspect the bowl is overflowing since you see gas come out. Either a float that sinks or more likely junk stuck in the needle valve where gas enters.
 
I think I have spark but haven't checked. I'll check into that tomorrow

No it wasn't raining saturday or sunday and everything was bone dry. as for "shooting back up out of the carb" I mean like a puff of smoke or could be gas mist, since i wasn't in front of the car to really tell. I ask my father to stand in front while i try and start the car.

distributor is brand new but I'll check into that tomorrow

float bowl vent baffle? first time I heard of it. I don't think i have that install. as for the gasket Im using the very thin gasket it came with. I have the two barrel intake with the adapter to fit the #2300 holley 350. are these the baffles?

I checked the float level through the side where a small nut bolt is and is right inline with the bottom opening of the hole. it seems to be at the right level and floats are freely floating (from what I can see through the little hole).

I do these test tomorrow and will let you know what happens
 

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Mopar King said:
it refuses to start and sometimes shoots out of the carb when too much gas is pressed.
Click to expand...

Again...from your words here. IF you do not have spark...it will flood and you will have gas come out of the carb when you press the gas. It does also sound like dirt but you have to make sure there is spark also.
 
Yes, those are float bowl vent baffles. Most people mistakenly throw them in the ditch.
 
With lots of respect to Triple R, I would not overly focus on the baffles at this point; the car WAS running without them before, right? Could be a good later improvement; but I have raced an inline 4 a lot with the 500 cfm version with no baffles and no issues. (But who cares about a race car idling smoothly? LOL)

The puff of smoke/gas vapors sounds like one step below a backfire, and indicates to me that that some of the sparks are waaaay off of time (especially with the stock cam, etc.). The ignition could be crossfiring under the distributor cap, or misfiring the spark for a number of reasons.

When you say you checked the timing 3 times, is that with the car not firing, or before the issues showed up? What kind of timing test do you use?
 
Exactly why I said "For when you get it started, food for thought."

I never said the baffles were making it not run. How frikkin stupid is that?


nm9stheham said:
With lots of respect to Triple R, I would not overly focus on the baffles at this point; the car WAS running without them before, right? Could be a good later improvement; but I have raced an inline 4 a lot with the 500 cfm version with no baffles and no issues. (But who cares about a race car idling smoothly? LOL)

The puff of smoke/gas vapors sounds like one step below a backfire, and indicates to me that that some of the sparks are waaaay off of time (especially with the stock cam, etc.). The ignition could be crossfiring under the distributor cap, or misfiring the spark for a number of reasons.

When you say you checked the timing 3 times, is that with the car not firing, or before the issues showed up? What kind of timing test do you use?
Click to expand...
 
after a few days of playing around with the engine. I found something that looks worrying, please give me your input / experience.

since the car has spark and fuel we still tried to start the car. It does stay on ONLY when you hold the gas pedal a certain way. it still shakes very rough and sounds loud. my father and me were thinking what could it be? when he decided to take the valve cover off just to see if there was anything wrong because the car was making alot noise and he was worry of a knocking sound. From first glance everything seems in place but when we started to shake a few of the rocker arms push rods - we were surprised that we could lift one of the rocker arm arms off the the valve spring retainer and the pushrod was off its track. i set the pushrod back in place; I think it was pushrod #2. Now i am wondering if this would be my cause of my car not starting and staying on... yes it still not starting :banghead:

hopefully i haven't confused anyone with my explanation. :eek:ops:

any advice on the pushrods, I haven't checked the push rods super carefully since it became dark when we decided to take a look inside the valve cover. why was the pushrod out of the tracking. I wonder where should i go from here. any advice im all ears
 
OK, so you threw a few pushrods? Take them out and roll them on a flat surface and see if they are bent. Replace as necessary. Now you got mechanical rockers on there, they need to be adjusted, they are not hydraulic lifters (unless its a late model, slim chance) A few dead cylinders would cause an otherwise sewing machine smooth slant to shake a tad....Then check timing, TDC with a piston stop or a drum stick in #1 spark plug hole and you turning the motor by hand until the stick just moves, mark balancer then turn the other way and mark that point of contact. right between those marks is TDC
 
If the car has not been driven much, then before adjusting the valves, I would do the following to check for stuck valves, especialy where the pushrods were thrown: Slowly rotate the engine by hand and as each rocker comes back up from pushing it's valve down, make sure each valve comes back up to the top of it's travel. (You can use a straight edge across the valve retainers as a rough guage for this.) And, check the pushrods as pishta suggests for bending. If bent, or even not, then you could have sticking valves.

Is there ANY old gas left in the tank? The gum in old gas can do this. If you have any doubts on this, then you need to try to work the valves loose, and then clean up the oil system.
 
This is starting to sound suspiciously like a timing jump.
 
Ok may I jump in here again. I have the same issue. Go back and see some of my old threads from last fall. Guess what I finally took the head in and this is what the shop told me. He asked if the car had been sitting and I said I just bought it and the guy told me it had not been driven much. This shop has been in business over 40 years and he is well known. He said he has never seen valves so gummed up in his life. They had to soak them to clean them. He said to get rid of the gas that is in my tank and clean everything. I am in the process of doing that right now. I could put new push rods in and get about 100 miles and it would bend #2 and #5 intake plus #3 bent once also. Crazy man
 
Oh and I had everyone tell me a timing jump as well. You need to check it but when I checked mine everything was ok and no play in the chain.
 
Here is how I found it. I compressed each valve down the line when I found a couple that were not working smoothly. They worked and the springs closed them as should but they just were not smooth like a few of the others. I thought maybe they were bent so I took the head into the machine shop.
 
just to not leave this unanswered... All new to me but Im still working on it


I order a few pushrods so i would have them on hand and not wait a day or two for them to arrive since they are special order. I replaced the push rod that was off its tracking.... yes it was bend

right now i also bought myself a compression tester so that i can check out each cylinder (in case). Im also going to check the intake and exhaust gap when the car is ON. I haven't done much but hopefully i can get everything button-up and finish by next week so i can take it for another test drive .


as for the timing chain, Its a brand new JP double roller timing chain so 95% i don't think it was a jump.


I sorry about the "title" since now that i know its not the carburetor fault but the pushrod that caused the trouble. I'll keep you guys posted until its finish
 

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Yeah, that pushrod has been 'field modified'.....! What have you done to clean up the valve guides and get the gum out to avoid more stuck valve issues? That is most likely the issue that caused this, and it may well re-occur with more bent p-rods if the guides are not cleaned out well. dartnabout's experience was this.
 
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