Good day all,

I have a pretty consistent problem with my '66 Toronado being difficult to start in the first start of the day when the temperatures warm up for the summer. Just looking for some advice on where to start. Original, '66 Qjet on the car currently.

My suspicion is that when the temps get warmer, something with the choke isn't setup properly but I'm not sure if it's a lean or a rich problem. Does that sound like I'm on the right track? The carb is in good condition and the car runs absolutely superb other than this one issue. Idles lovely, accelerates great with no sags, and full throttle feels good and strong. When the engine is fully warmed up it seems to start good, just need to give a touch of throttle when I start it.

When the outside temperature is fairly cold, I don't seem to have this problem even after sitting a couple of days. One or two pumps to set the choke and it fires right up after about 3-4 seconds of cranking. Now, with the ambient temps getting a bit high, I give it one pump to set the choke and try to start. Consistently, it almost immediately fires but quickly dies and I have to crank it and pump it to get it going again. After that, she's good for the day. I wonder if it is the choke pulloff not opening up enough just as the car starts and it chokes it out?

Other observations:
- The accelerator pump is one from Cliff Ruggles. I know his are the best in the business so I bought a couple and installed it myself.
- If I watch the carb when I operate the throttle, I see a good pump shot on the first movement of the throttle but they get weaker and weaker. By the 3rd pump shot, there's barely any fuel coming out. I checked, there is plenty of fuel in the bowl even when the pump shots are weak. I'm not sure if this is normal or not?
- I have the carb on the bench currently with fuel in the bowl and a paper towel underneath checking for leaking well plugs. It's been 24 hrs now and I see nothing on the sheet so far and there's still fuel in the bowl.
- When the ambient temps are fairly warm, should the choke butterfly be totally closed when you first set it?

 

Odd.

Choke issues generally become irrelevant when the weather warms up...

My car has the exact opposite traits. Can sit a month and start easily when its 50* and up. But can hard start when temps are around freezing or below or when cold and wet out. Mine has had choke issues forever, although last years adjustments have had her starting much easier and without needing to open the hood, etc.... (In my case the choke valve seemed to stay too open.)

Points ?

Gas quality ?

Bad spark plugs ?

 

There are others here who know choke theory better than me.

Cold Idle RPM
What little I know is you spring load the choke on the carburetor chock high step with that first gas pedal pump before startup.

The rpm’s you get from that high step on the passenger side of the carb is set the hex-screw, flat-blade or maybe a Phillips combo hex that sets the cold idle just a bit higher while the engine is cold. Look for it on the passenger side of the throttle plate, facing forward. As I recall it’s the only screw adjustment on the passenger side.

Once a cold internal combustion engine starts, it’s supposed to run higher rpm for a few minutes while the engine warms up. Higher RPM for just a few minutes helps the metal expand & gets your engine to efficient running temperature just a little faster. That cold start higher-rpm running condition finishes when you stab throttle the first time after start up, or when the bimetallic spring on your intake (1966 factory) or later on the carb (70’s) or the electrically operated one (75 & up) relaxes and lets the RPM’s down as a function of induced heat relaxing the choke spring.

What you can do on the bench is set the cold idle screw in 1/2-3/4 of a turn clockwise. Then put your adjusting screwdriver (probably relatively long small screwdriver) in your pocket. Cranking the cold idle screw clockwise raises cold RPMS. Turning it clockwise will cause your cold engine to race cold when you put the carb back on the car. But that racing signal will prompt you to have that setting screwdriver in your pocket to reduce it while the engine is cold to a target of 1100-1200 rpm.

That target of 1100-1200 rpm to keeps the cold engine running rich & a little fast before you hit the gas the first time _after_ the engine is running. If the relaxing spring hasn’t heated up, your driver throttle action mechanically releases the choke to the lower rpm step and you get back to that usual 750-800 rpm normal idle. The high-rpm start up applies in both warm & cold weather.

Choke Blade Angle (controls choke mixture for a few minutes after cold start)
The other part you want to optimize is the choke blade angle. Hard cold start usually means too lean.

You set the closed choke blade angle by (get this…) bending the passenger side control rod to make it more open (leaner) or more closed (richer). If I’m remembering right straighter is leaner, more bent is richer. Use pliers and work in very small increments (like 2-5°). For cold starts in warm or cold weather you want the air/fuel mixture richer than when the engine is at typical (180° or so) running temperature. Just like those crappy old lawn mowers we all remember… The goal on the choke blade angle is bending the rod via trial & error to find the best choke blade angle which starts the engine reliably year round. I don’t have knowledge, but I have gotten kind of lucky on this over the years. Too lean and you’ll crank forever. A little error on the rich side is the error you want to have.

Perfect angle adjustment is one gas pedal stab & it fires. That’s a great feeling.

Pumping Gas To The Carb
I’ll stay away from leaking qjet fuel wells here. If the car’s been sitting for a few days or longer, particularly in hot weather (or cold), you also have to factor in gas evaporation in the carb. Gasoline in the carb fuel bowl can evaporate. When it does, you’ll need to pump fresh fuel potentially up from the fuel pump or maybe even from the gas tank to the carburetor and wait for the bowl to fill so it can be accessed by the carburetor. Expect to crank the starter longer when you have not run the car for a while since there’s no gas actually in the carb.

Accelerator Pump Tips
On the accelerator pump side, you’ll need to remove the airhorn to see if the rubber pump skirt is frayed, cracked or split anywhere that fuel might leak upwards instead of the skirt seal forcing the fuel down past the (hopefully new) checkball and into the carb like it should do. I use the blue rubber pump skirts which are reportedly ethanol resistant. The big thing there is be sure the passages to the airhorn acceleration pump holes are clean and there’s no debris that could bock gasoline.

Practically speaking, what I do is use a multi-strand wire (14-18 gauge), cut the insulation off and spin it down the passages I want to clean. That applies to acceleration passages and all the others too. A clean, clean, carb is a happy carb. Clean means good metering.

If I feel any unsmooth surfaces in the cylindrical void of the accelerator pump, I clean those with #0000 steel wool. My view is imperfections can fray the pump seal skirt. Then there’s the old bit about not reusing a used-accelerator pump check ball. The rebuild kits come with a new one. Old timey advice is to tap a punch on the old one before removing it to re-round the orifice in the main body of the carb. Then you remove the old check ball and stick in the new one, knowing the new one is riding in a rounded hole.

Finally if you have multiple accelerator pump stems, compare the lengths on the bench. There were several lengths. I believe shorter lengths were a bigger pump shot and longer lengths were a smaller pump shot. If you’re not getting enough “shot” and have options, go for a shorter pump stem.

Battery, Starter & Charging
I also recommend stout, clean electrical cables and a fresh starter that doesn’t hesitate. Automatic Oldsmobiles were never meant to be push started so your charging/starting system has to be stout & reliable. I’m about to change out my starter motor since it’s starting to hesitate when hot. I’m not sure it’s the problem, but I want to eliminate that possibility on a 8 or 9 year old starter for a car that sits a lot. You can bet I’ll be dremel cleaning electrical connections & checking wires as part of that.

Maybe some of this helps you.

Chris

 

Yeah, I am really unsure what could be doing it. I've tried not using any choke at all but it cranks forever if I do that. The quick immediate fire - then die - thing is throwing me off. That happens when I pump once or twice, then try to start it when stone cold.

Things that have been done to the car:

1. Fuel tank was removed and cleaned out. It wasn't dirty, but I wanted to make sure. I have an endoscope and had a good look inside while I had the tank out and it's very clean in there.
2. New fuel pickup sock was installed.
3. All new rubber fuel lines installed.
4. All new 3/8" & 1/4" hardlines installed.
5. Fuel filter installed just prior to the pump inlet (Wix).
6. New fuel pump. Airtex model.......I know these aftermarket fuel pumps can be problematic but other than this starting issue, the car runs tip top.
7. New fuel filter in the carb (brass filter - early style).
8. New Champion plugs, points and condenser installed last year. Gave it a good tuneup as well. Dwell rock solid @ 30 deg, timing slightly bumped up to 9 deg BTDC.
9. I always use fresh Premium gas.

For whatever reason it seems that this car really wants the choke when you cold start it, no matter the temperature. Once its been started, it's really not an issue for the rest of the day.

 

I've got a good 2nd carburetor that I've gone through with a fine tooth comb. I got this one off John Herald Jr., who is an excellent QJet rebuilder, and I've got it on the car now so we will see how the car behaves with the other carb on it. The only thing is it's got the same choke assembly on it as I have to swap those parts to make one good carb. The replacement carb has main jets in it that are one size bigger than stock so it will be interesting to see how it behaves.

JHJ made sure that the problematic well plugs these early carbs were known for was corrected prior to sending to me.

 

Wow ok , you are very thorough. The issue is puzzling.

When I bought the 69 the fuel filter was installed backwards... didn't realize for a while.

She had a cacophony of issues leading to hard starting, and gas smell. It's tremendously improved since day one for me. Had to go over things over and over again to figure it out.

In any case I will keep mulling it over, and post if anything comes to mind.

 

Thanks! Yeah I actually didn't do all that stuff in pursuit of this particular problem. It's just that I did all that stuff a couple years ago, to repair all the neglected parts of the car when I first got it. The lines were old and leaking and I also needed to replace the fuel sending unit. I took the opportunity to freshen up the fuel system as it really wasn't all that hard to do. I had the tank out to replace the sending unit so I might as well handle the rest.

 

If warmer outside temps cause hard starting on a cold engine, I'd suspect a failing or improperly adjusted choke thermostat not closing the choke enough. When you suspect it will be a hard start remove the air cleaner, push the accelerator all the way to the floor, release the accelerator and check the choke blade position and tension.

 

So yeah, that's a really good idea but I'm not 100% sure on what it "should" be if it's adjusted correctly. Should it be fully shut closed? Should it open slightly when I crank it?

The choke thermostat, in my case, is mounted on the intake manifold. I actually ordered a brand new one from Fusick and it's a really nice quality item so it's probably not the problem although the attached link could be positioned incorrectly. So, I'd say you're right about the adjustment being off. I'm just not sure which way to go with it I guess. I'll have to have a really good look at it and give it a lot of thought. Maybe make a video.

 

The most important concern about choke blade adjustment is that it opens completely once the engine is at full correct operating temperature. Problems that can affect this are incorrect linkage, incorrectly adjusted linkage, a bad thermostat and a blocked heat crossover in the intake manifold.

Also very important is that the blade briskly closes completely on a cold engine.

If it opens completely then the tension on the blade may be increased in small increments if it doesn't close completely on warmer days. The adjustment can sometimes be accomplished by bending the choke thermostat rod a little at a time. I'd suggest not bending anything yet until we know whether or not the blade is completely closed during the long hard start condtion.

 

Excellent advice, thanks for this. I will do my best to study what's actually going on here and if I can record it, I will. I started up the car yesterday with the replacement carb on it but it immediately started leaking fuel from the inlet somewhere which was surprising because it didn't leak a couple days ago. I'll have to deal with that first I guess.

 

So yeah, I recorded the 1st start today and it behaved exactly like I mentioned. It definitely looks like it's too choked after start up. I'll bend the linkages so that it's less choked when it first starts.

Here's the video

 

Too much choke will cause a hard start when temps are warm - the mixture is overly rich and the engine can flood. When the engine is cold on one of these warm days, press the pedal once to set the choke, remove the air cleaner, and look at the choke flap. If it is hard closed, the choke is over-adjusted. The CSM will show you how to bend the choke rod to fix this problem.

 

Yeah, thanks Joe. That's exactly what is shown in that video I just posted. It's a stone cold engine, 1st start of the day on a pretty warm day. I think it's definitely over choked, like you said. It stalls right after it fires up.