67 Tri-power fast idle

[Bill K.]

I've search the forum and archives but can't seem to find a "Tri-power fast idle for dummies" thread.

On my 427/400 hp the fast idle cam does not engage. I recently installed new carbs but the issue existed on the prior set as well. Is there a document, photos, procedure etc for validating the mechanical assembly and function ? I don't want to start bending things etc in case my choke isn't working properly relative to the fast idle mechanism etc.

Thanks, Bill

[Bob H.]

Re: 67 Tri-power fast idle

Hi Bill:

I am surprised you haven't gotten a response yet. It is a quite simple heat controlled choke. The fast idle is controlled by a thermo coiled spring mounted to the manifold. Ir has a cover on it and is held in place with just one screw. The rod to the choke on the carb is attached to it. I don't think they are supposed to be adjustable but have had success adding or deleting tension as needed to the spring. New springs are available if you don't want to tackle it.

Bob

[John H.]

Re: 67 Tri-power fast idle

I've search the forum and archives but can't seem to find a "Tri-power fast idle for dummies" thread.

On my 427/400 hp the fast idle cam does not engage. I recently installed new carbs but the issue existed on the prior set as well. Is there a document, photos, procedure etc for validating the mechanical assembly and function ? I don't want to start bending things etc in case my choke isn't working properly relative to the fast idle mechanism etc.

Thanks, Bill

Bill -

You may find the attached linked file useful - the carb discussed in it (3367) has the same choke and fast idle arrangement as your 2300 center carburetor.

http://www.lbfun.com/warehouse/tech_..._Idle_Tech.pdf

[Bill K.]

Re: 67 Tri-power fast idle

Thanks for the link. I'm guessing the coil spring/rod is either not functioning or not connected/positioned properly to set the fast idle cam when the engine is cold.

[Bob H.]

Re: 67 Tri-power fast idle

Bill

You mentioned you changed carbs and neither worked. Remove the air cleaner cove so you can see what is going on.rYou should be able to crack the throttle open slightly and push up on the rod. The throttle must be open for the rod to move upward. Then release the throttle and see if it is on the fast idle cam. It should be. If it is then look to the coil as the problem.

Bob

Bob

[Stuart F.]

Re: 67 Tri-power fast idle

All of what you speak I just learned about tri-powers this past week on the bench. It is not all that difficult. Just use some common sense, although I must admit I'll take photos next time to speed the re-assembly. Actually, I grew to hate these carbs so there may not be a next time in my short years.

Stu Fox

[Bill K.]

Re: 67 Tri-power fast idle

Bob, the mechanism works when I actuate it manually i.e. I can open the throttle slightly by hand and move the cam up to the fast idle. Problem is I cannot get it to initially set on a cold engine with the gas pedal. Car is getting some chassis cleaning done so I can't go out immediately and look at it. From what you state it appears the coil may be the issue. I'm just looking for some guide on how it should work.

Thanks, Bill

[Michael J.]

Re: 67 Tri-power fast idle

Here is a photo of a spare 3660 carb I have for my L71. When it is cold, the choke should close and the cam will automatically move up and engage fast idle when you depress the throttle. If this is not happening, and you have to manually move the cam up, then I suspect the choke is either not moving to close or the bendable rod on the linkage from the dash pot needs to be adjusted so it will.IMG_1732.jpg