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52 cambridge..not starting..no fuel in carb


cruz

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My 52 cambridge is not getting gas to the carb..the bowl  is full on the lower  fuel pump...it starts right up when the carb is trickled..any info appreciated

Edited by cruz
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Does this only happen after you have been driving the car,park it for a short time,and then get back in it to start it? If it is,the heat from the exhaust manifold is boiling away all the gas in the float bowl after the car stops and the engine temps spike.

BTW,the first thing you want to do before you mess with it anymore is pull the dipstick and smell it to see if the oil smells like gas in case the float is hanging up and flooding the oil pan with gas.

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It ran well when parked this fall..I'm in Montana cold winters....full tank..fires right up when i tickle the carb..but its not getting any fuel delivery to the carb..bowl is full in the fuel pump..?...

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What does tickle the carb mean?

Does it run after you "tickle" the carb until it runs out of gas?

If the sediment bowl at the bottom of the fuel pump is full each time,that tells me the pump is pulling fuel up from the tank,so the problem must be at the carb.

Have you disconnected the fuel line going to the carb ,slipped a piece of rubber fuel line over it and then stuck that line in a container of some sort so you can have someone turn the engine over and verify that fuel is or is not running to the carb?

Have you taken the top off the carb to verify no fuel it getting to it  and to verify that the float is working properly? You can verify this by carefully  pouring gas in the carb until the float bowl floats to the top position if it is at the bottom of the bowl when you take the carb top off.

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Sounds normal to me. The carburetor is vented and the alcohol enriched gasoline sold today evaporates from the carburetor. It takes a while for the fuel pump to re-fill the carburetor bowl at cranking speed. Recommend you only use the starter in short 4-5 second bursts and wait 15-20 seconds between bursts all the while pumping the foot feed with the choke full on.

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10 hours ago, knuckleharley said:

What does tickle the carb mean?

Does it run after you "tickle" the carb until it runs out of gas?....

 

I usually "tickle" the Amal(s) on my old Bonnie to get her going.:)

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20 minutes ago, T120 said:

I usually "tickle" the Amal(s) on my old Bonnie to get her going.:)

Yeah,I  used to  have a TR-120 with Amal carbs,TT cams and pistons,so I am familiar with that,but Carter single brl carbs don't have a manual primer pump.

Or was it  "T-120R"? 1966 was a LONG time ago.

Edited by knuckleharley
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Check the clip that holds the flaot assembly in the top of the carb. Someone had a similar issue and they found that the spring clip that holds the float in place was not longer in the correct slot and had moved and the flaot was not working.

Just a thought.  Again what do you mean by tickle the carb.

Rich HArtung

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I believe Don is on the right path here. Something I might add from a recent personal experience is the fuel pump might be gummed up and not cycling completely. I had to take mine apart and give it a good cleaning with carb cleaner and it started pumping perfectly.

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Man Don is on fire today. That video brings back memories of my dad's 1965 BSA Lightning 650cc. It was stolen after he died and I still have the VIN number stashed away in case it ever shows up. I loved the sound and looks of that bike.

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56 minutes ago, Los_Control said:

the good ol prince of darkness, I drove the wheels off of a 69 triumph 650, was a fun bike.

It was Lucas electrics that convinced me to sell my bonnie and buy my first Harley,a 52 panhead. I had bought the Bonnie while on Okinawa in the army in 66,and sold it for 300 bucks more than I paid for it in 69. Took 250 bucks of that money and bought the 52 pan in Clinton,NC and rode it back to Ft.Bragg.  No more looking for a freaking rectifier in a small town like Warsaw,NC on a Sunday morning,and being hit up with 1 day AWOL because I couldn't get the part until Monday. Had to spend an extra day in the army because of that.

The pan got stolen,so I bought several boxes full of knucklehead parts,and build a 40 knuckle with a 3/4 rake,15 over 47 springer,74 inch flywheels and rods,.030 over pistons,SU carb,and a complete 37 Harley "lightening" valve train conversion. Jocket seat,peanut tank,and drag bars. That SOB was FAST and tracked like it was on rails. It got stolen,too. This time by one of my best friends,who was wise enough to move away in the middle of the night and not tell anybody were he went,and also wise enough he never came back.

Next one was a new 74 Shovel engine and trans put in a 58 FL frame with a half inch rake and lowered swing arm. Had a Sifton 458 (468s?) cam in it with a 1/3/4 S&S drag carb. It was pretty quick,but after about 40k miles I took it down and took the cases to a local Harley dealer to machine it for the S&S 112 inch stroker kit,and damned if it and everything in his shop disappear along with him. One day with no warning he just shut the doors and apparantely took everything with him when he left. What he didn't take was seized by the court and sold to pay off creditors. I  didn't know about this because my "local" Harley shop was in another state,and it was all a done deal by the time I found out about it. Still have everything but the engine.

Or did have. Had a house fire while I wasn't home back in the early 90's while I wasn't home,and evidently one of the firemen made off with some of the parts and special tools I had stored in the house.

My current one is a 76 FLH custom fatbob. It has the Sifton cam and SS carb off the other one,but no other engine mods. I've had this one since 1980.

Edited by knuckleharley
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By tickling... i mean putting a little fuel in the carb...it starts right up..but won't keep running unless i put more fuel in..the  fuel pump bowl is full.....sorry it took so long to get back..im working a buffalo hide at the moment..

Edited by cruz
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Ok you state the fuel bowel is full and I assume this is on the FP. But have you pulled the top of the airhorn on the carb to see if there is fuel in the bowl on the carb. The needle valve that  permits gas to fillthe bowl on the carb might be stuck. Sometime there is a rubber tit or tip on the needle and this might have gotten stuck or there might be something lodge inthis area.  You need to also check to see if fuel is even gitting pumped up the fuel line to the carb as has been suggested before.

 

Please verify what you have done on these two points and you might find the casue of the problem.  ALso might be the accelerator pump that is in the carb.

 

Rich Hartung

 

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There is a very simple test already mentioned in this thread to check the flow and quantity of fuel from the pump.  Did you do that test???  The bit of info missing was that 12 pulses from the pump should give you 8 or more ounces of fuel in your container.  It you are getting that then the fault is at the carb.  Likely something to do with the needle and seat and or the float.  If you are not getting that quantity, then there pump is not functioning properly and will not supply sufficient fuelto sustain a running  driving engine. Fuel in the bowl of the pump does not mean the pump is operating properly.  There could be debris in the pump restricting flow, there could be an air leak on the suction side of the pump, the flex line on the pump inlet could be collapsing under suction.  Your tank inlet filter may be clogged.  But that simple test will indicate where the problem lies and end speculation of which system is at fault.  

Basic trouble shooting has become a lost art/skill in this era of computer code pull and replace car repair. 

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