Printable View
I was just wondering why my old engines, when it is cold start right up but then stalls, starts right up and stalls again untill I get the throtal and choke in the right place. I start it by just pulling the choke out and hitting the starter. Sometimes I have to give just a little throtal. Are newer engins smart enought to control the mixture better?
Jeff
I have the same prob. but once the truck warms up it's good to goo. I've noticed this with alot of older vehicles.
Yes, new engines are smarter than the old ones. One big difference between the two - EFI.
Most old owner's manuals recommend full choke to start then immediately kicking back to about half that until the engine is warm enough to go on its own. For warmup you need the choke set where it's open enough to not flood the engine but closed enough to keep on the fast idle cam.
Chris
Gasoline the liquid does not burn. Gasoline vapor does. That is the job of the carburator, to airate or vaporize the fuel. Once the fuel is vaporized, the air/fuel mixture needs to travel to the cylinder together without the fuel dropping out. If this happens all you get is a bunch of air with little fuel inside your cylinder. Air does not burn. Neither does liquid gasoline. Cold engine + cold air + cold fuel means the fuel will probably drop out of the mixture inside the intake runner. Early designers solved this problem by blocking off most of the air going into the carb. The choke. The choke, chokes off the air allowing more fuel to be drawn into the cylinder. As long as the engine is turning above low battery speed, enough of the over rich fuel mixture will remain in vapor form to let the engine fire up. Once the engine starts though, it will draw more of the fuel rich mixture into it. This will actually put out the spark/flame inside the cylinders. The engine will stop running. This will repeat until the choke is let off enough to allow more air into the engine and less fuel. Once sustained running has been established, the engine will run in a rich condition until the engine reaches its operating temperature. When the engine is a temp, the fuel mixture can be returned to normal. The engine heat in the intake/head will keep the mixture in suspension. The cold air is more dense than warm air. Because it has more oxygen molecules in the same space, your engine will run better in the cold. This is basically what a turbo or supercharger does. Put more oxygen inside your cylinder, with the increase in performance equal to the increase in air.
For your cold starts, I would suggest the following. Pull the choke slowly out until you feel it pass the first detent on the throttle fast idle cam. Pump it once and try to start. Down to the mid twenty's that should work on a properly tuned engine. Different temperatures and states of tune will make you change things around some. Full choke is something that you really should never have to use. I hope this helps some.
Everyone.
Thanks for the answeres.
Jeff
Don't forget carb icing. Older V-8's have this problem alot. This will only show itself after a few minutes of running. The venturi effect can and will cause icing.
Ya know, up here in northern Wisconsin, at air temps of -30 to -40 F, I worried about carb icing and actually had a heat riser setup on mine for one winter. I took it off to do some work and didnt put it back on...I have never had a carb icing problem on mine, even temps as low as we get. Usually it is most common in the roughly 20-40 degree range, above zero that is, th damper the worse it is...have a ton of stuff on this from airplanes...no carb icing in those conditions is tolerable when you are flying.
With a 230 and a cooling system that is in proper shape, good antifreeze, not plugged in he adiator or passages, good water pump, carb icing shouldnt other ya. The intake has almost as much coolant in it as it does air/fuel mix...that really helps prevent icing.
Possibly others have had other experiences, but these are mine.
brute4c
The FAA makes all pilot know that any time it is between 30-70 degrees F carb icing is possible. It doesn't happen below that, because the moisture in the air is already frozen. Airplanes without fuel injection have a carb heat lever inside. Pulling this moves a valve in the air cleaner box. Air is no longer pulled through the filter, but from a riser surrounding the exhaust manifold. It results in about a 100-300 RPM drop in performance. Anytime you plan on reducing power to idle you should put on the carb heat and leave it on until full power has been reestablished, like when landing and then talking off again.
Glad you are doing good Jon.