before i proceed with the adjustments carbking suggested i did the following
>replaced fresh 5/16" fuel line from the can to the metal line going to the pump. it took less than 5 seconds to observe a healthy flow from the carb inlet
>replaced the line, pumped 3-5 times and without any prime in the carb it started
>gave a quick check for any obvious vacuum leaks, did not see any
>let it warm up but still having the same issue of stalling when opening the choke
please note this new observation... even with the motor idling with the choke closed for a while, if it stalls it will not start again without another 3-5 pedal pumps, i thought pumping is not usually necessary for restarts when the motor is warm, i dont know if this is particularly indicative of something?
Try to get the terms right. You can't get flow from an "inlet". Inlet is a place where something goes in. You were observing an outlet flow. I would not dwell on this if you weren't an engineer. Now, you are saying you now have good flow. Why? did it suddenly start pumping good and quickly? Don't hold back info even if you did something wrong. We need to know unless it's a miracle. Remember, you started this whole post by saying and confirming NO FLOW, 30 second wait, etc. Figuring out why it is now a good and quick flow is the rewarding part of working on trucks. It supplies info for all of us and helps in the continued effort. Did you or did you not, replace or exclude filter between pump and carb? Did you or did you not replace filter inside carb inlet? If so, then it sounds like the fuel level in bowl is not adequate or other carburetor issues. BE SURE to indicate info about the carb filter. This is at least the 4th time I have mentioned this. IF FILTERS ARE NEW, then it's time to rebuild carb. Rebuilding is a thorough cleaning out of all passages and parts. Then replacing parishible components and gaskets and setting a few parameters according to the instructions in the kit. All done in a clean big pan. Take pictures before of all sides of carb to be able to reinstall linkages correctly and pictures as you gently take apart. I will say you are a difficult poster to help. You don't respond to questions or advice, you don't provide specifics, you don't read the info given carefully. The stalling, heavy use of choke and pumping is indicative of fuel supply, as we have already informed you. Now that you supposedly have good supply out of pump, then it says the supply from carb to combustion chamber is the next issue. There are several things that could be causing it. The best approach is rebuild. I suppose there could be vacuum problems but I go with what you always say: not likely that something opened up just sitting. Very likely carb. Rebuild, get rebuilt, buy new. I don't rust many to build my carbs. Many are just practicing on my stuff. If they are older than 60, I may trust them. I would trust carbking, mike's carburetors and a few others.
when i first set out with questions and started cranking the truck after two years sitting i was not observing fuel flow, i primed the line and fuel has been flowing since. i tested flow with filters and without filters as suggested. i removed the carb inlet filter and it was clean and i could blow through it. while i am no expert all i can say is the flow looks very much like the reference video in the link.
i followed carbkings suggested outline carefully (i put a dab of paint on the screws prior to mark their baseline position) unfortunately it did not improve the idle, in fact it appeared to idle lower. note-when i filled the bowl with the ketchup bottle as suggested fuel did come out of the little "spring/rubber stopper like assembly" on the top of the carb - however i also noticed fuel leaking out of a small diameter hole in the iron base on the passenger side of the carb base and a small "pinhole" type hole in the iron base next to one of the carb mounting studs. i don't know if this is normal or not or what those holes are for?
being the exercise did not work i returned all the screws to the pre-adjustment position.
i will take the carb to be rebuilt by someone local who has a good reputation. incidentally if i wanted to buy a new carb where would you suggest looking? is the same type of rochester 2bbl carb specific to that motor readily available?
i will no doubt be needing other miscellaneous parts as well so i will create a separate post "parts vendors for these old trucks" this way others can benefit from any good information.
Carbking and others can answer. Those carbs are readily available in my world. Carbking is a good place to buy from. I would contact him thru his website, he does trade, sometimes, for carbs and other items. Many folks here have rebuilt many carbs. They all started with their first one. We didn't have these:
s/b a 7xxxxxx start with 7 and have 7 digits. Possible 17xxxxxx, doubt it. If it has a metal tag on one of the screws, that number is helpful. Having the tag is really cool! Sounds like you are on track.
If filling the carb with fuel, and setting the idle sufficiently high that the engine should run off of the main metering circuit did not allow the engine to get above idle, then:
(1) check the advance mechanism in the distributor.
Please go back to my post where I suggested, IN ORDER:
(1) Compression test (2) Ignition test (3a) Fuel delivery system (3b) Carburetor
I think you have other issues than the carb.
The vacuum value while idling would be a very useful number.
If you wish to discuss, 573-392-7378 (9-4 Mon-Tues central time).
Jon.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop
The forum is pretty good at helping folks with a certain problem. It's very hard to learn complete operation, testing, troubleshooting and repair of each system in a forum. (I know that is not what you are asking for). If you are interested in learning all about basic mechanics, it's best to get a motor manual for your motor/truck and go thru it. They have trouble shooting sections and explanations of operation. As soon as you can, time your motor, get new plugs, points, cap and wires. Set the points. A mild tune up is in order here immediately, no matter what the problem.
p5861 may I make another suggestion? In your profile you have NY. maybe if you would put an area you live in with out giving out your exact location. A near by Bolter might get in touch with you and come by and help. I know if somebody was near me I would be willing to help if I could. Good luck with your project.
Brian 1955.2 3100 Truck The older I get the more dangerous I am!!!!!
i installed the rebuilt carburetor today and the problem of stalling once the choke is opened is gone and the motor appears to be running well. the guy who rebuilt it said the idle circuits and jets were clogged.
once the choke was fully opened the idle was very low, i adjusted it by turning the curb idle screw and that raised it a bit. that said - whats the next step to making sure the idle mixture screws and curb idle screw are adjusted optimally?
the truck is not currently registered so i dont have the ability to run it on the open road, i am restricted to my driveway and perhaps a quick trip around the block
whats the next step to making sure the idle mixture screws and curb idle screw are adjusted optimally? thanks
The easiest way is to hook up a vacuum gauge to the manifold vacuum port and adjust the fuel air mixture to get the highest and steadiest reading. Then use the idle speed screw to set the idle around 450-550 rpm. Vacuum gauges can be had fairly cheap from Harbor Freight and/or other tool-centric shoops as well as FLAPS. Dave
Personally, I would suggest used tools made in the USA.
Sears / Penske engine analyzers take care of the need for tach, dwell, and a host of other applications; and were excellent quality. Make sure the original book, as well as the leads/cables comes with the equipment.
Jon.
Good carburetion is fuelish hot air The most expensive carburetor is the wrong one you attempt to modify. If you truly believe "one size fits all," try walking a mile in your spouse's shoes! The Carburetor Shop