then how does that increase the idle. adding more fuel would richen it but without the throttle open more id figure it would flood.

 

Hey Hotrod,

Hope you don not mind if I hijack your thread, but I would love to ask a few questions to the experts on here. It does pertain to what you are asking so we can all learn something here.

Living in South Florida, I use to never use my enrichner. Now I do, because when I am ready to ride, I like to crank the bike and let it warm up while I get my jacket, helmet, gloves, close the garage door, what ever I have to do before I ride off. I do not like getting all ready then just sitting on the bike blipping the throttle to keep it running while it warms. I have also used the previous mentioned method of cranking and using the throttle lock to open the throttle a little.

I am not even concerned about fouling plugs, because they are cheap and change them out often anyway. My question is; If I am using enough enrichner to foul my plugs (which I don't think I have) what does that do the walls of the combustion chamber? If there is carbon build up in the chamber, will carb cleaner sprayed into the carb with the engine running break up the carbon and blow it out of the exhaust? Am I over thinking this issue and is this no issue at all? Thanks guys.

 

hey there wideglide95th, nice 65 mustang, my wife drives a 70 mustang, great cars. my paint use to look as good as yours but arizona heat has taken its toll, its her daily driver. anyway i believe that too much gas washes the cylinders. gas doesnt make as good a lube as oil. ive heard stories of washing rings out in engines, ive never done it, but people have told me to push down the enrichment valve as soon as i could. im still trying to figure out how adding more gas makes a motor idle higher, now if it also creates a vacuum leak also then that would do it. S&S doesnt go into to much detail on how it works other than it enriches the motor.

 

Speaking to carbon in the cylinders, carb cleaner at idle won't do it. Ever watched a car floor it and see black smoke out the back? Not an expert by any means, but think it has to do with more fuel, (duh) and increased compression by more gas making a bigger bang. Like, open her up and blow the carbon out.

 

After thinking on it a minute or two, maybe it has to do with the temp of the motor, why when cold you can choke it, and it'll run, but when warmed up it'll die right away if you choke it. Must be someone that can explain this, or I won't sleep good tonite.

 

Accepted your friend request hotrod. Thanks, but I don't have the Mustang any more. Got rid of it in 03 when I got this bike.

Right or wrong, this is the way I see it. Hopefully some one will come on here and help us out. The enrichener adjust the A/F ratio to account for the cold engine, therefore an increase in rpms. My understanding is that the enrichner adjusts the fuel where the old typical choke adjust the air. On an FI model this is done by the computer. When I had to use the choke on my old cars and trucks there was also an increase in the idle speed until the engine warmed, then the engine would start to stall by running too rich.

I don't think you would have to worry about the extra gas in the cylinders unless you did not crank it and let it sit. By running your engine afterwards, that would eventually burn the extra gas on top of the cylinders. A little excess gas in the oil would also be evaporated if the motor is run long enough. I have a friend that has a wide glide that he only runs 1/4 mile to work and home. I would be concerned if that was my bike, because the engine never does reach operating temp. My bike also has a vacuum operated fuel shut off valve that I am in the habit of turning off when I park the bike just in case gas is leaking past the valve and sitting on the cylinders.

Someone please educate me if I am wrong!

Mike

 

Aaahhh yes, thanks for pointing that out, fuel enrichment vs. choking the air supply. Fuel enrichment, kinda like those bulbs on the lawn mower to prime the motor, I think I'm starting to get the jist of it. Never thought there was so much science involved for all the years I've been working on motors.

 

Took motor mechanics class in hs, never occured to me to ask why you need to choke a cold motor, or maybe I did and the answer was, because its cold.
this is starting to get too deep for me.

 

Fuel does not atomize as well when cold. And with the carb body, intake tract, heads cold fuel just wants to puddle. In order for the fuel/air mix to be stoichiometric and burn, you need to add more fuel. As soon as the engine warms up and atomization becomes more efficient, you can decrease the amount of extra fuel. An enrichener fuels through its's own ports and passages. A Choke restricts airflow at the inlet of the carb upstream of the venturi. This creates a greater pressure differential at the venturi and more fuel is drawn from the float bowl. (The atmospheric pressure on the outside of the carb is higher than at the back side of the venturi and fuel is actually pushed through the jets and into the carb.) On a choke equipped carb, you generally have a cam to open the throttle butterfly some to allow an equalization of air flow due to the restriction of the choke.
To complicate things a little more, a CV carb has a variable sized venturi to attempt to keep the air velocity over the metering jets constant regardless of engine speed.

(It's been over 35 years since shop class, but this stuff sticks in your head if you use it all the time!)

 

Thanks Moog Player!!! Is that a more scientific way of saying what I said? It explains why a cold engine needs a richer mixture.