Wont Idle

[dennis]

I picked up a 72 510 all original a few weeks ago. I just finished up the brakes and now I am working on getting the motor running. This is what happens, I fire it up and it starts but then quickly dies no matter how hard I step on the pedal. I have already drained the old gas and refilled with premium and replaced the fuel filter. If I spray starter fluid in it starts and runs till it dries out. Spark is good, timing should be good enough to at least make it run.

 

I am not good with carbs and the only experience I have is with an old holley carb. I do not want to buy a weber 32/36 since I will be doing a motor swap next year. I also have a rebuild kit for the hitachi but I know the mechanic who owned it last just rebuilt it a couple of years ago, I know that doesn't mean he did it right.

 

Any suggestions?

[datzenmike]

The front of the carb has a glas cover with a horizontal line about 2/3 of the way up. Fuel should be at that level.

[dennis]

The front of the carb has a glas cover with a horizontal line about 2/3 of the way up. Fuel should be at that level.

 

If not then the float is off?

 

I think it is around halfway up, I will check in the morning.

 

Thanks Mike.

[datzenmike]

Then it should run.

 

Possibly there is a blockage in the primary circuit and no fuel getting through. Motor off ,look down the carb and work the throttle... you should see a strong squirt of fuel from the accelerator pump into the primary barrel. (one closest to the valve cover)

[dennis]

Then it should run.

 

Possibly there is a blockage in the primary circuit and no fuel getting through. Motor off ,look down the carb and work the throttle... you should see a strong squirt of fuel from the accelerator pump into the primary barrel. (one closest to the valve cover)

 

I looked down and can hear a faint squirt, but cant see anything. The fuel level is 2/3 full on the sight glass.

[datzenmike]

On the valve cover side are two adjustment screws. They have a spring under them. The one on the side is the idle mixture screw. Try turning it out a turn. This will richen it slightly but I doubt this will keep it going.

 

If you can get it to fire up (briefly) then it should be able to suck fuel into the primary through the primary jet. The bottom of the float chamber may be filled with sediment and blocking the jet.

 

What's the history on this car? Has it been sitting for years or did this happen suddenly? If it sat the gas will eventually evaporate leaving a varnish like crap in all the jets and air bleed orifices in the carb. You may have to take it off and clean/re-build it. For sure by the sound of it the accelerator pump is bad. (no squirt)

[dennis]

On the valve cover side are two adjustment screws. They have a spring under them. The one on the side is the idle mixture screw. Try turning it out a turn. This will richen it slightly but I doubt this will keep it going.

 

If you can get it to fire up (briefly) then it should be able to suck fuel into the primary through the primary jet. The bottom of the float chamber may be filled with sediment and blocking the jet.

 

What's the history on this car? Has it been sitting for years or did this happen suddenly? If it sat the gas will eventually evaporate leaving a varnish like crap in all the jets and air bleed orifices in the carb. You may have to take it off and clean/re-build it. For sure by the sound of it the accelerator pump is bad. (no squirt)

 

Well I bought it from a guy and he said it has been sitting for a year. Prior to that year he said he rebuilt the carb and it was running fine . I believe this because he kept alot of the spare parts in the trunk and it the box was a carb rebuilt kit that stored the old gaskets.

 

Thanks for your help Mike, I will give your suggestions a try tomorrow and if this doesn't work I will try to clean out the primary jet and clean the float chamber.

[datzenmike]

The p/o may have put it together wrong!

[dennis]

The p/o may have put it together wrong!

 

I know, I hope not. The PO did take good care of it tough, but who knows.

[dennis]

Well I cleaned out the float chamber and the sight glass (didn't know there was a line on the glass). Opened up the idle screw and nothing I then reset it back to 2 turns out from the seated position. I rebuilt the accelerator pump while I was in there as well.

 

I am starting to think that it might not be the carb after all. Any suggestions.

[jesusno2]

check for air leaks around the base of the carb with some carb cleaner. I really hate those carbs when they dont work their just such a pain to get to work. If you cant get it to work, and you really would like to drive your 510 get a weber 32/26 if you have the money. Their the best thing for any stock L series engine in my opinion.

[dennis]

check for air leaks around the base of the carb with some carb cleaner. I really hate those carbs when they dont work their just such a pain to get to work. If you cant get it to work, and you really would like to drive your 510 get a weber 32/26 if you have the money. Their the best thing for any stock L series engine in my opinion.

 

Thanks, but the carb is sealed up really well. It is a matter of money, I dont want to spend 280.00 for a carb that I am only going to use till Jan.

[dennis]

Well I have an ad in the wanted section for a 32/36. If no takers in a week or two I will probably just buy a new one.

[datzenmike]

Maybe check the valve lash and a few things first and get it running before spending the money.

[dennis]

Maybe check the valve lash and a few things first and get it running before spending the money.

 

I was going to do valve lash today after I make a trip to Sears for some tools I am missing to do the job.

[dennis]

Also, when you start it up with starter fluid it runs when you keep spraying starter fluid in it.

[banzai510(hainz)]

pump the gas pedal!!!!!!

Do you see a stream of gas going in there? everytime you push or cycle the linkage you should see gas going in there. Motor should run off the accell pump cause your bypassing the idle circut. look the left side of carb see if gas is being squirted in.

 

So does it stay somewhat running when key is switched back to the ON key position. If dies in ON position then usually its a dirly contack in back of key swithc where the plug hooks in.

 

this is a EZ fix.

[dennis]

pump the gas pedal!!!!!!

Do you see a stream of gas going in there? everytime you push or cycle the linkage you should see gas going in there. Motor should run off the accell pump cause your bypassing the idle circut. look the left side of carb see if gas is being squirted in.

 

So does it stay somewhat running when key is switched back to the ON key position. If dies in ON position then usually its a dirly contack in back of key swithc where the plug hooks in.

 

this is a EZ fix.

 

I pump it and it still dies. Gas is squirting in with the pedal. It was squirting before I cleaned out the float chamber as well. I just couldn't see it before but once I had the carb off I could clearly see it.

 

Also, on the accellerator pump should the linkage be mounted on the top hole of the brass fitting or the bottom? I copied the way it was mounted before so I stuck it on the top mount position.

 

I will play with the key later on today and see if it tries to stay on.

[banzai510(hainz)]

If gas is getting squirtted in it let almost pouring gas in from the top with a can. You pump long enough the manifold will fill up with enough gas to run soemwhat. Should be a nice steady stream when cycleing the gas

 

Since you just got this rig I would adjust the valves and ck the points and distributor for anything obvious and gap the points.

 

as for the key ON swithc I have had where my car will run in Start but key goes back to ON it will shut off.

One way to ck is see if you have 12volts on the Blk/white wire that goes to tha ballast resisitor(the white ceramic block.) If you have 12volts with Key on or test light its OK.as other suggest ck intake for loosness as I have had loose intakes also.

[dennis]

If gas is getting squirtted in it let almost pouring gas in from the top with a can. You pump long enough the manifold will fill up with enough gas to run soemwhat. Should be a nice steady stream when cycleing the gas

 

Since you just got this rig I would adjust the valves and ck the points and distributor for anything obvious and gap the points.

 

as for the key ON swithc I have had where my car will run in Start but key goes back to ON it will shut off.

One way to ck is see if you have 12volts on the Blk/white wire that goes to tha ballast resisitor(the white ceramic block.) If you have 12volts with Key on or test light its OK.as other suggest ck intake for loosness as I have had loose intakes also.

 

Thanks, I will look into all of it. The carb was barely bolted on.

[dennis]

The ballast resistor is seeing 12vdc.

 

I wont be able to fire it up till later on and test the key theory as well as adjust the valve lash.

[datzenmike]

Check both sides of the ballast. You may be checking the ignition side but the ballast is broken and nothing getting to the coil.

[dennis]

Check both sides of the ballast. You may be checking the ignition side but the ballast is broken and nothing getting to the coil.

 

I am assuming you want me to test the impedance of the resistor? If so do you know what it is supposed to be? I did some searching and found a 1.6ohms but I want to make sure that number is correct.

[datzenmike]

No, as long as power can flow through it it's fine. These things get hot and when old they can break. This will cut off the power in the run position. It will start when the key is in start but when the key returns to the on position the motor quits.

[dennis]

No, as long as power can flow through it it's fine. These things get hot and when old they can break. This will cut off the power in the run position. It will start when the key is in start but when the key returns to the on position the motor quits.

 

edit: Retested, ballast is reading 12.48 and 6.69 @ 1.6ohms so that is working perfectly