Engine only starts when carb is choked with palm

general gow

general gow

Member
I've been trying to get the A started. I managed to get it started today by putting my palm over the carb to give it choke. Choking it via the rod, it won't start, even though the butterfly is closing.

Any idea what's going on?

Thanks in advance, fellas.
 
sounds like an air leak . pos between carb & manifold, Otherwise strip carb & clean it , looking for blockages. Derek from Wet NZ
 
We had one like that. We just got it running and while one person choked it another ran the RPM's up and let it race while the person on the carb choked it and let it off kind of like plunging a toilet. Sometimes this will dislodge anything that is blocking a jet. I vote for a blocked jet.
 
Is this a new car for you, or is this a sudden new problem on a car that has been running?

Either the gas flow to the carb is very poor, or the carb is blocked in the jets or passages.
 
i should mention that i have had the fuel delivery system apart including the shut off valve, the lines, and the fuel filter. all that is clean as can be now that it's been blown out, and delivering fuel properly.

i don't have a glass bowl on the carb, and the screen tube is clean and shiny.

i'll mess with it the way you did, James, and see what i get.
 
Do not mean to state the obvious, but you may be holding the choke out for too long.
Cold start, have mixture [ gav] open 1/2 to 3/4 , pull choke, push starter, & let go just after starter engages, ie. before engine fires . It should fire up when you release choke if carb. is all correct. I see that you are 'new to Model A's' so no disrespect to you. Good luck.
 
Have you checked the fuel inlet screen in the top of the carb? You have to remove the large nut on the end and if the screen hasn't been out for many years it may have to come out in pieces with a needle nose plier.

Someone posted an excellent cutaway picture of the carb, but I don't recall who did it or where to find it.
 
general gow said:
doesn't like to idle. vacuum leak somewhere?
Click to expand...

The simplest explanation is that the idle jet is blocked. This is a common problem. In my experience, there is an easy fix, which I call the carburetor Heimlich--you've already come close to doing it.

Get the motor running and set up the hand throttle so that it is idling fast enough to keep running--it will be running on the main and secondary jets. Set the e-brake in neutral; open the passenger side hood; with your right hand on the throttle linkage, momentarily race the motor to high rpm while you simultaneously cover the carb's air intake with the palm of your hand (probably smart to use a glove); before the motor has time to stall, remove your hand and release the throttle. Repeat a few times if necessary. The idea is that, with the intake covered, the entire vacuum generated by the racing pistons is sucking on the idle jet--it WILL be cleared.

If this doesn't work, I think there is something seriously wrong with the carb.

Steve
 
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