Rebuild, replace or swap moms 510 carb/engine?

Engine, Transmission and related drivetrain.
510wagon
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Joined: 30 Jan 2017 16:55
Location: Los Angeles Ca

Re: Rebuild, replace or swap moms 510 carb/engine?

Post by 510wagon » 12 Apr 2019 12:34

This is great directions and very much appreciated. I’m going to do this right now but this screw here keeps running itself in and changing the idle. I’m going to put blue locktite on it or a locking nut on it to hold it in position. It has like very low resistance where I can turn it with my fingers. It is the correct bolt because it has no axial play, just screws in and out very easily. Anyways I want to ask if it’s position is important before “locking” it in place. Does this have any role into setting the idle and air/fuel ratio by the directions you just gave me?
It seems just like a linkage adjustment bolt? Thanks for all your help again!
datzenmike wrote:
07 Apr 2019 13:18
The slotted screw near the carb base next to the vacuum advance pipe is the idle mixture adjustment. The idle speed screw is just out of sight behind that spring. Set the idle as low as you can (in neutral and thoroughly warmed engine, naturally) and then slowly turn the mix screw in or out whichever improves the idle. Try 1/4 turns and wait a few seconds for any improvement or worsening of the idle. When you have the idle as improved as you can get, turn the idle speed back down and repeat the mixture adjustment looking for the fastest smoothest idle you can, turn down the speed and repeat. This may take 7 or 8 tries but when the idle cannot be improved and the speed is around 700 or so you're done. Have someone hold the brakes on and place in DRIVE while you adjust the idle speed back up to 650-700. A good strong idle with high manifold vacuum is essential when driving an automatic.
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RMS
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Re: Rebuild, replace or swap moms 510 carb/engine?

Post by RMS » 12 Apr 2019 13:40

im not familiar with the auto carb but I believe that screw is for the choke speed. the idle screw should be beside the mixture screw ? haynens manual pg 61 fig.3.26 (your carb is not pictured?)
two_68_510s wrote:I guess our donkeys are quicker then your sled dogs!

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James
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Re: Rebuild, replace or swap moms 510 carb/engine?

Post by James » 15 Apr 2019 19:31

Where did you end up with this?

Curious......
Finished is better than perfect......

510wagon
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Joined: 30 Jan 2017 16:55
Location: Los Angeles Ca

Re: Rebuild, replace or swap moms 510 carb/engine?

Post by 510wagon » 16 Apr 2019 11:49

James wrote:
15 Apr 2019 19:31
Where did you end up with this?

Curious......
I drove it about 30 miles Saturday. Then about 10 miles Sunday. It’s does drive better with the new ignition points. Haven’t put the plugs, wires, rotor in yet. I have came down with a fever yesterday but I will when I get well. BUT the car does not nearly run good. It’s hard to start and bogs at low rpm acceleration. Once it gets about half way through a gear shift it runs good. I suspect the accelerator pump and electric choke are faulty. I looked down the throttle body when the engine is cold and pressed the accelerator and did not see the squirt of fuel that I would suspect would be there. I did hold open the butterfly valve and use a flashlight. Also I forgot to get a fuse for my multimeter to check voltage for electric choke but I will.
And I didn’t get a answer on that screw I asked about so I didn’t set my idle, air/fuel mixture that mike recommended. Once I get better I’ll just lock it in anywhere then do what he said.
Any recommendations would be greatly appreciated.... by anyone.

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bertvorgon
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Re: Rebuild, replace or swap moms 510 carb/engine?

Post by bertvorgon » 16 Apr 2019 14:49

How is the throttle shaft on that carb? If you grab the shaft where the throttle arm hooks up..and try to wiggle it up and down...does it move? If it moves at all other than rotation, that shaft is done. IF it does, that is a big issue for trying to tune something, as air gets in that way.

Is that "bottom" gasket on the carb good, where the carb bolts to the manifold. One easy check for air leak is to spray some brake clean around that base, with engine running, see if the engine speed changes at all, IF so, there is an air leak there.

Who "re-built" that carb? It is possible they got jets mixed up, just say'in.

That carb looks really rough. For a carb that was supposedly rebuilt, those gaskets sure look old

Did you adjust the valves or know how to do it?

Wish I was there to help you.
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Keith Law
1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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