How at adjust idle?

[DannyDot]

What is the procedure to adjust the idle on a C-85 engine? I see a screw to the left (as you face the plane) of the idle adjust screw. Is this a set screw that needs to be undone before the idle adjust can be turned? Looking at it close up, I don't see how this other screw can function as a set screw, but I don't see any other function it can perform.

Danny Deger

[crispy critter]

Re: How at adjust idle?

The throttle arm will come back against the set screew behind the throttle arm.To slow down the idle simply back the screew out a turn or two and this will allow the throttle control to come back farther. Adjust half to one turn at a time until you get the desired idle speed you want.If you want to speed the idle up,simply run the screew in rather then out.

[Ragwing nut]

Re: How at adjust idle?

The other screw in the middle of the carb is the idle mixture screw.

Mike

[crispy critter]

Re: How at adjust idle?

The other screw in the middle of the carb is the idle mixture screw.

Mike

that is correct but it doesn't do much for the idle speed,it just adjusts the amount of air mixed with the fuel. If it is too rich it will load up,mis,etc. If it is too lean it will be hard to start,stumble very easily when trying to advance the throttle,etc.

[Ragwing nut]

Re: How at adjust idle?

that is correct but it doesn't do much for the idle speed,it just adjusts the amount of air mixed with the fuel. If it is too rich it will load up,mis,etc. If it is too lean it will be hard to start,stumble very easily when trying to advance the throttle,etc.

correct I was just identifiying since it sounded like he did not know what it was for.

Mike

[crispy critter]

Re: How at adjust idle?

Oh,sorry Mike. I just wanted to make sure he didn't try to fix the idle with the low speed mixture. We best watch ourselves.....if we confuse him too much he might end up with the carb mounted up-side-down....and running,LOL.That would be a neat trick.

[DannyDot]

Re: How at adjust idle?

Oh,sorry Mike. I just wanted to make sure he didn't try to fix the idle with the low speed mixture. We best watch ourselves.....if we confuse him too much he might end up with the carb mounted up-side-down....and running,LOL.That would be a neat trick.

Thanks for the concern, but I do know the difference between a mixture control and an idle RPM adjustment. I think I will get a picture of the setup to show the second screw I am talking about. It is not the idle mixture. It is on the thottle control assymbly and is about 1/4 inch to the starbord of the idle control screw.

I have found an A&P to do the actual work, but want to learn all I can myself. I have owned aircraft in the past and found it possible A&Ps don't know everything And as I am finding out on this and other discussions, there is more than one way to skin a cat.

Danny Deger

[Ragwing nut]

Re: How at adjust idle?

Thanks for the concern, but I do know the difference between a mixture control and an idle RPM adjustment. I think I will get a picture of the setup to show the second screw I am talking about. It is not the idle mixture. It is on the thottle control assymbly and is about 1/4 inch to the starbord of the idle control screw.

I have found an A&P to do the actual work, but want to learn all I can myself. I have owned aircraft in the past and found it possible A&Ps don't know everything And as I am finding out on this and other discussions, there is more than one way to skin a cat.

Danny Deger

Learning is the best thing and you are right mechanics don't know everything. I will have to look at a carb to see what you are reffering to.

Mike

[DannyDot]

Re: How at adjust idle?

The throttle arm will come back against the set screew behind the throttle arm.To slow down the idle simply back the screew out a turn or two and this will allow the throttle control to come back farther. Adjust half to one turn at a time until you get the desired idle speed you want.If you want to speed the idle up,simply run the screew in rather then out.

Mystery solved. The second screw is a set screw to keep the idle RPM screw from turning.

Danny Deger