It Runs, but a little rough

[Charley]

After a year of on-again-off-again work, I started the engine this weekend and took my first test drive. What a charge! I couldn’t believe the responsiveness from the 2.7. I bought my ’74 911 from a guy who froze the engine in 1999 and hadn’t driven it since.

I still have a lot of work to do (obviously, as you all know). My main problem is the idle, which won’t hold steady below 1800 RPM. I set the timing and dwell and put injector cleaner in the gas tank. The valves, which were assembled and set by a San Diego machine shop, are VERY loud. I don’t know if it's affecting the idle, but I just ordered the gauge, so I can fix it next weekend. I installed new vacuum hoses when I did the rebuild and the car starts right up when warm (so I’m assuming it’s not the accumulator). The threads that I’ve been reading lead me to thinks it’s a vacuum leak; the idle doesn’t drop when I remove the oil cap. I ended up with two disconnects from my rebuild (see pictures below). There’s a tan and gray wire that wasn’t connected when I bought the car and I’ve never found a home or it. I also have an unidentified vacuum device that I never hooked up. The small nipple on the right side of the charcoal canister is the likely suspect, since it’s unconnected, but plugging it with my finger doesn’t make any difference to the idle.

My plan is to adjust the valves and then find a mechanic that knows what he’s doing. Any thoughts?

Thanks,

Charley

[Jim Sims]

The item with the hose is not a vacuum component. It is the drain valve off the bottom of the air box. The plastic portion with the rubber duckbill type valve mounts outboard on the sheet metal at the passenger front just above the starter. The hose connects to a barb on the bottom of the airbox. Jim

[Jim Sims]

See drain mounted to left of starter in the below image.



Jim

[dweymer]

I just bought my 74, and I think I have the same wire not connected, I will check.

[Charley]

Thanks Jim. Below is picture of a barb that I thought was unused on my car. I put my finger in it and it felt closed off.. Does the other end of the duckbill valve go there?


Don, thanks for looking for the wayward wire.

Charley

[Jim Sims]

No, the drain hose goes on the bottom of the black plastic air box to the left and up from the nozzle circled. The nozzle circled is not used in 1974 (see below thread) but in later years (1975 onward) was connected to the auxilary air and additional air valves. Jim

It Fires...with a little help! Fuel Line Question

[Charley]

Jim,

Again, thanks. I'll find it.

[dweymer]

Checked today, mine is not connected to anything either. I have an idle around 2k also, but it will come down if I pull the linkage by hand. Still trying to find the bind.

[Charley]

Thanks Don. When I get my car to idle below 2k, on a regular basis, I'll post another thread to let you know what it was (or what I did).

Charley