carb adjustment

[Anonymous-0]

i'm trying to adjust the idle on my 1952 8n. can't get it to idle much below 900 rpms without dying. the idle jet has no effect on the idle. will the idle jet even come into play if the engine is running at 900 rpm's? or is it more likely that the jet is just stopped up? if i can't get the idle down to 400, how will this effect the timing?
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cjm

 

[Dunk]

My plan would be to take the carb apart, and make sure that I could blow thru every hole, and orifice in it with a rubber tipped air compressor blowgun.

Kinda the way your governor works, the mechanical, centrifugal advance in your distributor changes the engine timing with engine speed.

 

[russb]

CJM, regarding: [i:654c4848f0]the idle jet has no effect on the idle.[/i:654c4848f0] Just so you know, inward is leaner, seemed counter intuitive to me.

 

[Tom N MS]

Actually inward is to enrich and outward is leaner on the idle adjustment screw.

 

[8N'r--WI]

CJ--you write--will the idle jet even come into play if the engine is running at 900 rpm"s?--NO, your engine is running too fast.

Before you start cleaning out the carb, I would reset the main idle screw out 1 1/2 turns, the side pointing idle mix screw out 1 1/4 turn.

Then with the engine running, adjust the "behind the carb" idle screw down until the engine is running at between 400-600 rpms. At this speed when you adjust the "side pointing" idle mix screw either "in" for inrich or "out" for lean, you should hear a noticeable change in engine speed.

Remember to adjust the side pointing idle mix screw for maximum RPM"s not smoothest running RPM"s.

If this doesn"t work, I would follow Dunk"s recommendation on cleaning out the carb.

Tim

 

[Britcheflee]

I was given a slightly different method of adjustment not for the idle but for the higher rpm screw - unscrew this out about 4-5 turns, then get the engine running at about 1/2 to 3/4 rpm then gradually screw this back in a leeetle bit at a time - when it starts to stumble back it off half a turn - let it settle down then maybe a tiny bit more out. I discovered my 8N needs that screw (the one facing the radiator) backed out quite a bit more than the book states - maybe because the carb is old?
Problem for me is that with no proof meter or other method to show rpm I have to go by 'ear' as to what sounds right with the engine as far as the slow speed idle is concerned.


Lee

 

[cjm in tx]

thanks guys. i'll try all the suggestions.
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cjm

 

[Kenster]

CJM, where are you located? I'm between Bellville and Brenham.

 

[cjm in tx]

i'm down south in corpus christi.
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cjm