Ooof, a fuel minutes of idling with the choke and rich mixture is a great way to wash out brand new rings and glaze the cylinder walls. Huge no-no.

Whenever I conduct a break-in, I always use a known good running carb from something analogous so I know that I will at least be close on startup.. choke wired fully open. Running rich right off the first start is absolutely terrible for new rings, as is prolonged idling for the first few minutes. You need to get that thing fired up, set your timing as fast as possible, and get that RPM up right away. Your timing should be pretty close before startup already. I decide ahead of time what I want my initial timing to be, set the engine to that position (say 10° BTDC #1), then install the distributor and set it in that position, with the magnetic pickup in the distributor lined up in the firing position for that cylinder. This will get you pretty close - I am always within 2° of my target with this method. Have your timing light already hooked up ready to go, distributor hold down semi-snug so you can turn it by hand with some resistance but not loose enough to move on its own. Set it, snug it down and get that RPM up right away. NO prolonged idling after after break-in, NO choke usage until the rings are definitively seated.

 

I'm aware of initial timing and it'll be close.
no other engine to run this on and no other carb available. I'm sure it'll be fine. Is the procedure in the op correct otherwise.

 

Do not gloss over what I said about the choke and prolonged idling. Huge no-no. Wire the choke fully open, fire it, set the timing, quickly adjust mixture screws for best vacuum, and get that RPM up RIGHT AWAY. Seconds, not minutes. I can’t stress that enough. The only idle speed adjustment you need to worry about is to crank that screw down quickly to bring the RPM up. You are NOT fine tuning the whole carb on initial startup. You worry about fine tuning idle speed, choke setting, all that stuff later. You only get one chance to properly seat your piston rings.

 

If its a new carb good idea to take it apart and check it over . Common to find machining chips inside , also check float level by turning bowl upside down to see if float is roughly centred a little higher (when upside down) would be a lower fuel level which would be better than high till you get time later to fine adjust . Agree with having a fast idle and have some coolant handy to top off rad , a little choke might be better than excessive accel pump shots but get it open as soon as possible . I'd check timing before fine adjusting mixture , if it starts to overheat shut it down and let it cool down till you figure out why , low coolant , thermostat , retarded timing , wrong water pump etc.

 

You can "dry time" the engine in just a few seconds, before actually starting it. No fuel in carb, so it can't start. Timing damper and timing pointer marked with bright paint marker. Position distributor rotor at 15-20 degrees BTDC on the damper/pointer on number 1 cylinder compression stroke. (or 35 degrees if locked out distributor.) Timing light hooked up, after verifying it works on another engine. Minimum surrounding light, to clearly see timing light pulses. Crank engine for a few seconds, with remote starter button, ignition on, and verify timing is close enough to start. Once started, vary RPM 1500-3000 for 15 minutes stationary (or drive car to put a load on it to help rings seat.) Have a water hose handy to run over radiator if needed. Fill radiator with front of car up in air to let air pockets escape. If electric water pump, fill radiator with pump running to 1" from top and cap while still running.

 

You really need someone in the seat holding the rpm up and watching gauges - oil psi and water temp - while you are running around setting timing and looking for leaks,topping off the rad.... Like said no idling. Hold it around 2 - 2500 rpm.

 

Use the carburetor idle stop screw to bring the RPM up, that way it CANNOT drop below where you set it. People can get distracted and forget what they’re supposed to be doing. Use the screw to bring it up to 2,000 and use the throttle to vary it from there. Or, just turn the screw back and forth slowly like I do.

Every break-in I do is on a run stand with gauges on it. You don’t bring the RPM up until after you set the timing. Your cooling system should be absolutely full before you fire it, you shouldn’t leave these things to mess with after startup. Fire it, make sure you have oil pressure set the timing, quickly make sure idle mixture is close, rev it up using the carb screw. Simple stuff. You don’t need to worry about coolant temp at this stage, it’s still cold.

 

Definitely take the carb apart before running it. Between my nephew and I we've had three Quickfuel carbs in the last few years. The first one came with the wrong jets ( i.e. way off factory specs ). The second one had crap in it, and the power valve channel restrictor wasn't installed. It was loose in the float bowl. My most recent one, a Q-950 had one of the air bleeds filled with brass shavings. All were great carbs, but wouldn't have been if they hadn't been taken apart and checked first.

 

I have no idea what any of that means. I need to grab a book about carburetors

 

So it does not need a load on it?

 

The “load” you need to put on it for the initial 20-25 minute break-in is just varying the RPM from around 2000 to 2500 the entire time. Steady up and down the whole time, because the differing oil splash patterns ensure oil is evenly distributed, the cam is broken in properly and the piston rings see slight load and coast cycles. Once initial break-in is done and you change the oil, then you can properly load it by driving it or running it on a dyno.

Different people will tell you different things regarding whether it’s better to do WOT dyno pulls vs. street driving. I’m of the opinion that for a street engine, I prefer partial load by driving it, with an equal mixture of steadily increasing throttle inputs starting around half throttle or so, followed immediately by a coast of roughly the same amount of time. That’s my typical routine. Absolutely no prolonged idling or steady state cruising for the first couple hours. Find a place without traffic where you can conduct this break-in the right way, without being hindered by traffic or other issues.

Lots of people will say go straight to WOT dyno pulls or street driving, and it obviously works for tons of them, I just don’t find that necessary for a typical street engine. But it’s still important not to baby it, and not to do any steady state cruising or idling for a while. Most of the time it should not take all that long for the rings to seat - a matter of a few miles worth of mid-throttle acceleration and coasting cycles. But I maintain the no idling or cruising rule for the first couple hundred miles regardless.