Kennyc135 Posted February 13, 2021 Report Share Posted February 13, 2021 Lately, every time I get on a decent stretch of road that isn’t stoplight to stoplight, my Cranbrook starts to hesitate and will stop firing for several seconds. I let off the throttle, and usually it’ll pop and crackle a little bit. I’ll slowly start to ease back into the throttle and it’ll be fine for another several seconds and then repeats. It’s completely hit or miss when it actually does it. Idles fine, usually accelerates just fine. I’ve got new plugs, wires, cap and rotor, new coils. Checked the gap for the plugs and the points. I’ve tried the three different settings on the Carb for the accelerator pump to see if that changed anything and no luck. No signs of the coil overheating or anything. Can’t determine if it’s fuel or ignition related, or something else entirely. It’s typically when I get up to speed, let’s just say 35 mph. It starts to happen within 10 seconds or so after getting up to speed. Not sure if it’s getting too much fuel and flooding it for a second or what the issue is. Any ideas on what to check on next? Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted February 13, 2021 Report Share Posted February 13, 2021 (edited) based on your post info....my first go to on this is fuel starvation.....check for good flow, no pinholes where the pump would draw air and not fuel....possible clogged filter and if mechanical fuel pump, the screen on the inlet....next in line would be the possibility your float is out of adjustment and not allowing for enough reserve in the reservoir for sustained speeds... Edited February 13, 2021 by Plymouthy Adams 1 Quote Link to comment Share on other sites More sharing options...
Los_Control Posted February 13, 2021 Report Share Posted February 13, 2021 Sure sounds like fuel starvation to me. Certainly would be the first things I would eliminate. 1 Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted February 13, 2021 Report Share Posted February 13, 2021 You stated you checked the gap of the plugs and the dizzy. But what are the setting that you used? Are they over or under the correct gap? Please let us know. How are the small inner wires on the dizzy? is the cloth covering exposing any of the bare wires or anything rubbing against metal. If you have the FP that has the glass bowel on the bottom of the unit then take this off and clean it and check for sediment also check the small screens in the base of the FP to make sure they are also clean of any sediment. Was the Coil a new coil or a used coil. It might be breaking down internally? Just some thoughts. Rich Hartung desoto1939@aol.com 1 Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted February 13, 2021 Report Share Posted February 13, 2021 good point Rich....if the vehicle was running fine up to the point you FIXED it via tune up...I would advise you to review your work...if you did the tune up as a factor to correct existing condition...still leaning toward fuel starvation... Quote Link to comment Share on other sites More sharing options...
Kennyc135 Posted February 13, 2021 Author Report Share Posted February 13, 2021 17 minutes ago, desoto1939 said: You stated you checked the gap of the plugs and the dizzy. But what are the setting that you used? Are they over or under the correct gap? Please let us know. How are the small inner wires on the dizzy? is the cloth covering exposing any of the bare wires or anything rubbing against metal. If you have the FP that has the glass bowel on the bottom of the unit then take this off and clean it and check for sediment also check the small screens in the base of the FP to make sure they are also clean of any sediment. Was the Coil a new coil or a used coil. It might be breaking down internally? Just some thoughts. Rich Hartung desoto1939@aol.com both coils I have put in were new, and the issue started well after the tune up. The gaps were all set spot on. Not over or under. I’ll have to check and see which fuel pump I’ve got and go from there. Do you know roughly where the fuel filet would be at on one of these? Inline along the frame rail maybe? It’s -8° out right now here so I’m trying to get as much info as I can before I have to go outside and freeze my butt off haha Quote Link to comment Share on other sites More sharing options...
Plymouthy Adams Posted February 13, 2021 Report Share Posted February 13, 2021 fuel filter stock were air stone style (sinister metal) inside the tank itself...why often if trash is in the tank it will collect at the filter and block the ability to flow adequate fuel and may be why when you let up it will build up just enough fuel for the operation at lower speed. Not to say that over the years a PO may have added a filter along the frame or just before/after the fuel pump. This you have to do an inspection to validate... Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted February 13, 2021 Report Share Posted February 13, 2021 Refer to Plymouthy Adams reply regarding the fuel filter.. When it gets warmer the go check the car to cold to be working on it right now. When you get some time blow some compressed air back from the fuel pump connection of the rubber hose and have the gas cap off. Have someone listento hear if they hear the air bubbles inthe tank. The line might be getting clogged at the outlet from the tank. If you have a glass bowel on the FP again check to see if there is crud and or an accumulation of gunk and rust particles in the bottom of the bowel. If you are getting this situation then you have rust inthe tank. Might want to drop the tank clean it out and then install an inline fuel filter, where the fuel line exits the gas tank and then another one inline just after or before the fuel line goes into the carb. If you put one in the engine compartment I would suggest that you do not use a plastic inline filter but get a good metal body unit that has the glass bowel so you can keep an eye to see if there is sediment in the bowel. Can also use fuel line cleaner in the tank a good product is the New Stabil 360 product and it is sold at Walmart and they have the cheapest price. This is a little different than their red fuel stabilizer product. do some reading on the product. I use it regularly in my 39 Desoto especially during the winter months when the car is sitting in the garage for several months Rich Hartung Desoto1939@aol.com 1 Quote Link to comment Share on other sites More sharing options...
Kennyc135 Posted February 13, 2021 Author Report Share Posted February 13, 2021 Fuel pump gas no sediment bowl, and definitely no added on inline filter. So I pulled the top of the carb off and saw that the accelerator pump wasn’t even close to touching the top of the spring retainer. (The bowl doesn’t have much fuel in it at the moment because I was pumping the throttle linkage to see how the accelerator pump would react. The float looked about right at the 5/64 that it should be, didn’t take the time to properly measure though when I saw the pump.) Should it be safe to assume that it’s time for a new pump and spring? Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted February 14, 2021 Report Share Posted February 14, 2021 I do notice that there isa lot of tarnish in the downdraft section of the carb and also tarnish and deposits in the bowel area where the accelerator pump is located. I would suggest that a total rebuild is needed. You can go to Harbor Freight and get a sonic cleaner to soak the parts in to clean out the carb parts. Also here is another suggestion. Get two cardboard egg cartoon containers and label each hole starting with Number 1 thru 24. As you take each part off the carb put in in the respective hole inthe container. Be careful there are two small ball bearing in the base of the carb. They are small but they are different sized ball bearings do Not and I say Do Not get them mixed up. This is why you make the and number the egg carton. Then to reassemble you start with the last part and work back to number one. This makes the process so simple. Also soak the leather accelerator pump in a little light oil to get the leather to become soft and then it will make a good seal to draw up when it is going up and down. Rich HArtung desoto1939@aol.com 1 Quote Link to comment Share on other sites More sharing options...
Los_Control Posted February 14, 2021 Report Share Posted February 14, 2021 Looks pretty severe to me ... wonder how it ran at all .... looking at what we can see, ya have to wonder at what we do not see. I wonder what caused all the tarnish in the down draft area? Could it be the new modern fuels we have? I would take it apart and clean it, then re-assemble with a rebuild kit .... maybe just a good cleaning is all you need? Quote Link to comment Share on other sites More sharing options...
Kennyc135 Posted February 14, 2021 Author Report Share Posted February 14, 2021 Before I bought the car, it sat in storage for close to 30 years. Previous owner had a mechanic that got it running but the guy never really got to drive it before he ended up needing to sell it. That being said, it could be dirty from sitting for all those years and never being cleaned since who knows when. Carb definitely could use a good cleaning and a rebuild kit. It is definitely starving of fuel, I got it to act up while driving it and limped it home, parked it, and just sat on the throttle a little until it died. Took the top of the carb off and sure enough, the bowl was empty. Now it just comes down in I figuring out why it’s it getting enough fuel to the carb. I’m thinking I’ll probably have to pull the fuel tank and clean all of that out, see how rusted it is, possibly replace it. And definitely pull out the fuel pump and check it over. Other than that, it’s just straight lines that lead up to the carburetor. Compressed air should clean them out I would hope. Quote Link to comment Share on other sites More sharing options...
Sam Buchanan Posted February 14, 2021 Report Share Posted February 14, 2021 (edited) You can dink around with the rusted fuel system or fix it once and for all. New tank, gauge sender, lines, pump, carb rebuild and verify fuel cap vents. That will be the last time you need to mess with the fuel system. Edited February 14, 2021 by Sam Buchanan 1 Quote Link to comment Share on other sites More sharing options...
soth122003 Posted February 14, 2021 Report Share Posted February 14, 2021 4 hours ago, Kennyc135 said: Before I bought the car, it sat in storage for close to 30 years. If it sat for that long, I'd bet dollars to donuts that the rubber fuel line just before the fuel pump is toast and collapsing when the suction from the FP gets ramped up. Also you said a mechanic got it running but it wasn't driven much before selling the car. Check your air filter assy and make sure there is no crap in there that is getting sucked into the carb and causing problems. Joe Lee Quote Link to comment Share on other sites More sharing options...
pflaming Posted February 14, 2021 Report Share Posted February 14, 2021 Several years ago I rode with a friend to the California BBQ. He had a very nice 47 Plymouth. On the way home, the engine did just as you describe. It would run great the slowly lose power and finally quit. After stopping band tinkering, it revived. By coincidence, it was discovered that the top bolts of the carburator bowl were loose enough to let the gas evaporate. Tightened those four bolts and “bobs your uncle” problem solved. Those bolts need good lock washers. I hope this helps. Quote Link to comment Share on other sites More sharing options...
Sniper Posted February 14, 2021 Report Share Posted February 14, 2021 12 hours ago, Kennyc135 said: the accelerator pump wasn’t even close to touching the top of the spring retainer Not supposed to be touching it. Looks pretty much the same as mine does and I don't have those issues. But regardless, a good cleaning and rebuild does look to be in order. 1 Quote Link to comment Share on other sites More sharing options...
DonaldSmith Posted February 14, 2021 Report Share Posted February 14, 2021 The step-up piston, on the left of Kennyc35's photo, has some function at speed. James Douglas stated some time ago that ethanol in the gas can corrode this piston, inhibiting its function. I found that this piston in my carburetor has some corrosion. Every few years I take the top off the carburetor and make sure that this piston is free. I don't know if this is contributing to the problem at hand. Quote Link to comment Share on other sites More sharing options...
greg g Posted February 14, 2021 Report Share Posted February 14, 2021 The step up piston or power valve augments the initial squirt from the accelerator pump. It consists of a tapered needle which slides up and down through a jet. The default position is up with the spring holding it wide open, providing maximum gas flow through the jet enriching the air fuel mix. There is a vacuum hole in the base of the carb that allows high manifold vacuum to pull the piston down closing the flow through the jet. This vacuum signal come through a slot in the carb to intake manifold. Some rebuild kits have one slot, some have four slots and some have no slot. If the vacuum signal is not provided, the valve will be open all the time causing an override mixture causing cylinder washing, plug fouling, miss tires and poor performance at cruise and under acceleration. Black exhaust smoke under load may be present. Fuel mileage will be in the 10 miles per gallon neighbor Hood. Assure the assembly moves freely, has the correct spring, the needle is free of deposits, the jet is clear and the vacuum path is provided for and flows sufficiently to close the jet. The picture show he rebuild gasket with four slots that goes between the carb and intake. Any vacuum leaks via perished gasket or loose fitment will provide an insuficient vacuum signal to the step up. Quote Link to comment Share on other sites More sharing options...
RobertKB Posted February 14, 2021 Report Share Posted February 14, 2021 10 hours ago, soth122003 said: If it sat for that long, I'd bet dollars to donuts that the rubber fuel line just before the fuel pump is toast and collapsing when the suction from the FP gets ramped up. Al Ditto. Definitely worth checking. I have had this happen. Quote Link to comment Share on other sites More sharing options...
greg g Posted February 14, 2021 Report Share Posted February 14, 2021 I chased a problem for a couple months a few years ago. Turns out there was a piece of debris (chunk of hose as it turned out) It had positioned it self in the fuel pump inlet fitting so that increased suction at higher rpm would cause it to act like a check valve. Idle all day, yep, rev in neutral with no load yep, drive 40 all day, yep, pull out to pass nope,. climb a long hills nope, finally pulled off the fuel pump, cleared it out back to normal. Also don't forget there is a mesh screen inside the pump that can get fouled also. Quote Link to comment Share on other sites More sharing options...
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