I have never used an engine choke before. Can anyone tell me how to position an outboard engine choke when starting and when running? Responses appreciated.
Choke
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Choke? Cough! Cough! 
Start the cold engine with the choke engaged. Once it starts, push the choke back in to operating position else it will cough and quit. A warm engine may, or may not, require choking. It depends on how warm it is. Experiment. Good Luck!
Start the cold engine with the choke engaged. Once it starts, push the choke back in to operating position else it will cough and quit. A warm engine may, or may not, require choking. It depends on how warm it is. Experiment. Good Luck!
choke to start
Here is what you do to cold start with a choke. Choke full out; throttle 1/4, then as the motor warms push the choke in in increments until it idles at low rpm, as you lower the throttle. Here is what you will hear. As the motor warms up and the rich mixture vaporizes better in the carb, you will hear the rpms start to drop. Pushing the choke in will raise the rpms. Reducing the throttle will lower them again. The trick is to keep a balance between the two, until the motor is running smooth at low rpms with no choke and little or no throttle. Here is why you do this. When you pull out the choke, you reduce significantly the air supply thereby increasing the fuel to air ratio, making a richer mixture. As the engine warms up and vaporizes the fuel better, the mixture gets too rich and becomes starved of the air it needs to burn, therfore the rpms drop. As you push in the choke, it opens up and lets in more air, and the rpms rise again. The smaller the carb, the finnikier the motor is to start, because you are playing with a smaller volume of fuel and air. If your engine cowling is off, and the carb does not have an air filter on it (most outboards don't), any wind will reek havoc with the air supply in the carb, thereby making starting more difficult. Keep the cowling on, unless you are mucking with the carb settings, and if you are do so out of the wind. I learned this lesson this past week.
Here is what you do to cold start with a choke. Choke full out; throttle 1/4, then as the motor warms push the choke in in increments until it idles at low rpm, as you lower the throttle. Here is what you will hear. As the motor warms up and the rich mixture vaporizes better in the carb, you will hear the rpms start to drop. Pushing the choke in will raise the rpms. Reducing the throttle will lower them again. The trick is to keep a balance between the two, until the motor is running smooth at low rpms with no choke and little or no throttle. Here is why you do this. When you pull out the choke, you reduce significantly the air supply thereby increasing the fuel to air ratio, making a richer mixture. As the engine warms up and vaporizes the fuel better, the mixture gets too rich and becomes starved of the air it needs to burn, therfore the rpms drop. As you push in the choke, it opens up and lets in more air, and the rpms rise again. The smaller the carb, the finnikier the motor is to start, because you are playing with a smaller volume of fuel and air. If your engine cowling is off, and the carb does not have an air filter on it (most outboards don't), any wind will reek havoc with the air supply in the carb, thereby making starting more difficult. Keep the cowling on, unless you are mucking with the carb settings, and if you are do so out of the wind. I learned this lesson this past week.
Every outboard
...seems to have its own unique way it wants to start. For example, I had a new 8hp 2-stroke Evinrude some years ago. Right from the getgo, it "required" the choke to pulled out all the way, a little bit of throttle, and then pull the start cord. As soon as it began to turn over,you had to push in the choke immediately or it would cough and die. I always started that engine with one hand on the start cord and one hand on the choke as a result. It "required" no choke at all when warmed or after having been started in the past 3-4 hours not matter how cold/hot the temps were. Play around with your motor and find its "sweet spot." It'll let you know when have or have not found it...
...seems to have its own unique way it wants to start. For example, I had a new 8hp 2-stroke Evinrude some years ago. Right from the getgo, it "required" the choke to pulled out all the way, a little bit of throttle, and then pull the start cord. As soon as it began to turn over,you had to push in the choke immediately or it would cough and die. I always started that engine with one hand on the start cord and one hand on the choke as a result. It "required" no choke at all when warmed or after having been started in the past 3-4 hours not matter how cold/hot the temps were. Play around with your motor and find its "sweet spot." It'll let you know when have or have not found it...
The choke isn't that simple
No one mentioned partial choke. Mine needs 1/2 choke to start when it is fairly warmed. It likes 3/4 choke when it is cold on a warm day. I spent 1/2 an hour last night trying to keep my weedeater running to clean it out. It required tweaking the choke between 3/4 to 7/8 (roughly) to keep it running at all. Then it died completely. I think the carb is gummed up. My point is that a choke isn't an on/off type device. It's a mixture control. Cold engines like a richer mixture - the colder, the richer (within bounds). They also like slightly retarded spark timing, but most engines don't have that lever anymore. You probably also need to be made aware of how to deal with a flooded engine (too much gas) which everyone who plays with the choke experiences sometimes. There are two ways: let it sit a while or open the choke, hold the throttle wide open, and run (or pull) the starter, which tends to pump the excess out and briefly runs the engine up (fast, if you aren't watching for it) when the gas in the cylinder becomes lean enough to ignite. Then it dies if it is cold and you don't pull the choke out some quickly (not too much too soon or you'll flood it again). It wasn't really an easy question, so the answer isn't likely to be either.
No one mentioned partial choke. Mine needs 1/2 choke to start when it is fairly warmed. It likes 3/4 choke when it is cold on a warm day. I spent 1/2 an hour last night trying to keep my weedeater running to clean it out. It required tweaking the choke between 3/4 to 7/8 (roughly) to keep it running at all. Then it died completely. I think the carb is gummed up. My point is that a choke isn't an on/off type device. It's a mixture control. Cold engines like a richer mixture - the colder, the richer (within bounds). They also like slightly retarded spark timing, but most engines don't have that lever anymore. You probably also need to be made aware of how to deal with a flooded engine (too much gas) which everyone who plays with the choke experiences sometimes. There are two ways: let it sit a while or open the choke, hold the throttle wide open, and run (or pull) the starter, which tends to pump the excess out and briefly runs the engine up (fast, if you aren't watching for it) when the gas in the cylinder becomes lean enough to ignite. Then it dies if it is cold and you don't pull the choke out some quickly (not too much too soon or you'll flood it again). It wasn't really an easy question, so the answer isn't likely to be either.
Choke additional question
Thanks to everyone that responded, just one additional question: once my outboard is "fully warmed up" do I keep the choke all the way in? I have had my motor stall at very vital times when mooring my boat or traveling through high traffic areas but I never pushed my choke all the way in. Could this be my problem?
Thanks to everyone that responded, just one additional question: once my outboard is "fully warmed up" do I keep the choke all the way in? I have had my motor stall at very vital times when mooring my boat or traveling through high traffic areas but I never pushed my choke all the way in. Could this be my problem?
Yes
...that could be your problem. You shouldn't engage the engine with the choke on - just use it for starting. Let it run a few seconds and push it in while using the throttle to keep things moving until it warms up. Good luck!
...that could be your problem. You shouldn't engage the engine with the choke on - just use it for starting. Let it run a few seconds and push it in while using the throttle to keep things moving until it warms up. Good luck!
Choke additional question
Once the engine is fully warmed up, you should not need the choke. If a warmed engine won't idle without the choke, then it needs a tuneup. Standard disclaimers follow. I'm no expert - grain of salt - etc. This is how I'd do it: You can perform a tuneup while moored or tied to a dock (or underway if you've got plenty of room, and someone to steer while you're tweaking). The engine should be in gear and loaded (not under sail). If you can keep the engine running in gear w/o the choke by just adding more throttle, do so. The engine should be fully warmed up. The choke provides extra fuel to the carb, for when the engine is cold. If it won't idle w/o the choke, you need to open the fuel mixture screw to provide more fuel. Find the carb mixture screw (it's not used to attach anything - the screw shaft runs through a coil spring - it runs directly into the carb). Turn the screw counter clockwise, making very slow, small adjustments (5-10 degrees/second), and keeping track of how far you're turning the screw from the start position (in case performance gets worse - you can back up). Listen carefully. The engine should start to speed up. If the engine starts racing, back off on the throttle. If the throttle is at it's slowest setting, and the engine is still racing, you need to back off of the "idle speed screw". This is a screw near the carb, that limits the motion of the throttle linkage, controlling how slow you can set the throttle. You can find it by moving the throttle back and forth repeatedly, and watching the linkage. Reduce the throttle so that the engine idles as slow as possible w/o stalling. Continually repeat the mixture adjustment, then the throttle adjustment, until further unscrewing of the mixture screw causes the engine rpms to drop. At that point, the carb is flooding with too much fuel. Turn the screw back in, and find the position that gives you the highest rpms. If this is much above a reasonable idle speed, back off on the throttle and adjust the mixture again. As you get closer to dialing in the mixture and idle speed settings, your adjustments should get smaller and smaller. Eventually you should get to a point where the engine is at a slow but steady idle, and any mixture screw adjustment beyond a small range causes the rpms to drop, and reducing the throttle slightly more causes the engine to start stalling. Leave the mixture screw in the middle of this range. Adjust the idle speed screw limit to a little above the stall speed. All this is done in gear. Now that you're idling in gear, when you shift to neutral, the engine will speed up, but hopefully it won't be racing. Shifting at high rpms is damaging to the gears. If it is idling fast in neutral, a temporary solution is to back off the idle speed limit screw, and just try to remember that you need to give it some gas as soon as it goes into gear.
Once the engine is fully warmed up, you should not need the choke. If a warmed engine won't idle without the choke, then it needs a tuneup. Standard disclaimers follow. I'm no expert - grain of salt - etc. This is how I'd do it: You can perform a tuneup while moored or tied to a dock (or underway if you've got plenty of room, and someone to steer while you're tweaking). The engine should be in gear and loaded (not under sail). If you can keep the engine running in gear w/o the choke by just adding more throttle, do so. The engine should be fully warmed up. The choke provides extra fuel to the carb, for when the engine is cold. If it won't idle w/o the choke, you need to open the fuel mixture screw to provide more fuel. Find the carb mixture screw (it's not used to attach anything - the screw shaft runs through a coil spring - it runs directly into the carb). Turn the screw counter clockwise, making very slow, small adjustments (5-10 degrees/second), and keeping track of how far you're turning the screw from the start position (in case performance gets worse - you can back up). Listen carefully. The engine should start to speed up. If the engine starts racing, back off on the throttle. If the throttle is at it's slowest setting, and the engine is still racing, you need to back off of the "idle speed screw". This is a screw near the carb, that limits the motion of the throttle linkage, controlling how slow you can set the throttle. You can find it by moving the throttle back and forth repeatedly, and watching the linkage. Reduce the throttle so that the engine idles as slow as possible w/o stalling. Continually repeat the mixture adjustment, then the throttle adjustment, until further unscrewing of the mixture screw causes the engine rpms to drop. At that point, the carb is flooding with too much fuel. Turn the screw back in, and find the position that gives you the highest rpms. If this is much above a reasonable idle speed, back off on the throttle and adjust the mixture again. As you get closer to dialing in the mixture and idle speed settings, your adjustments should get smaller and smaller. Eventually you should get to a point where the engine is at a slow but steady idle, and any mixture screw adjustment beyond a small range causes the rpms to drop, and reducing the throttle slightly more causes the engine to start stalling. Leave the mixture screw in the middle of this range. Adjust the idle speed screw limit to a little above the stall speed. All this is done in gear. Now that you're idling in gear, when you shift to neutral, the engine will speed up, but hopefully it won't be racing. Shifting at high rpms is damaging to the gears. If it is idling fast in neutral, a temporary solution is to back off the idle speed limit screw, and just try to remember that you need to give it some gas as soon as it goes into gear.
A little more on tuneup
"Yes" to the adjustments mentioned above. Except that you'll be busy, and you probably ought to tie up somewhere to do all that. In addition, the problems can also come from bad fuel, clogged fuel filter, gummed up carb, poor spark, mistimed spark (on some engines), vacume leakage, and/or a worn engine. It could even be valve adjustment and/or timing. And/or other things I didn't think or don't know about. The ones I mentioned easily fall within the realm of "tune up" in the large sense. Your tuneup may require filters, cleaning the fuel system, new or cleaned and regapped plugs, minor maintenance, point gap adjustment, ignition timing (on the odd motor), valve clearance adjustment (on the oddest of motors), and carb cleaning. Go find the manual for your motor. Do ALL of the maintenance things required. Then do the tune up work. Adjust the screws last. If that doesn't work, take it to a pro or get a new one.
"Yes" to the adjustments mentioned above. Except that you'll be busy, and you probably ought to tie up somewhere to do all that. In addition, the problems can also come from bad fuel, clogged fuel filter, gummed up carb, poor spark, mistimed spark (on some engines), vacume leakage, and/or a worn engine. It could even be valve adjustment and/or timing. And/or other things I didn't think or don't know about. The ones I mentioned easily fall within the realm of "tune up" in the large sense. Your tuneup may require filters, cleaning the fuel system, new or cleaned and regapped plugs, minor maintenance, point gap adjustment, ignition timing (on the odd motor), valve clearance adjustment (on the oddest of motors), and carb cleaning. Go find the manual for your motor. Do ALL of the maintenance things required. Then do the tune up work. Adjust the screws last. If that doesn't work, take it to a pro or get a new one.
dial 2stroke outboards
Try this: With somebody driving take the cowl off the ob so you can get at the carb. there are three screws to be concerned with on a two cycle outboard carb. Fast mix, idle mix and throttle position.(Idle speed adjistment) throttle up under load to full power. set the high speed mix screw to max rpms. 1/4 turn is a lot so turn slow. backing the screw out should increase rpms untill the engine will cough from too lean of mix. when the engine coughs turn the screw in about 1/8 turn. Motor should be singing. Next throttle down and repeat the same proceedure with the low speed mix screw. This time when you back the screw out go slow. It will be easy to kill the motor. Same thing, when it first coughs turn the screw back in 1/8 turn. If the low mix is already too lean the coughing will start as soon as you throttle down. If this is the case turn the screw in about 1 turn to keep it running and then lean it out. Lastly set the Idle speed adj. Do these in order or you will be chasing your tail. In circles. I have a collection of 2cycle outboards and some have mix knobs on the front right next to the choke. Makes it easy to dial the mix for day to day conditions. I use my runabout in Colorado and the different altitude lakes make a huge difference in the mix tuning.
Try this: With somebody driving take the cowl off the ob so you can get at the carb. there are three screws to be concerned with on a two cycle outboard carb. Fast mix, idle mix and throttle position.(Idle speed adjistment) throttle up under load to full power. set the high speed mix screw to max rpms. 1/4 turn is a lot so turn slow. backing the screw out should increase rpms untill the engine will cough from too lean of mix. when the engine coughs turn the screw in about 1/8 turn. Motor should be singing. Next throttle down and repeat the same proceedure with the low speed mix screw. This time when you back the screw out go slow. It will be easy to kill the motor. Same thing, when it first coughs turn the screw back in 1/8 turn. If the low mix is already too lean the coughing will start as soon as you throttle down. If this is the case turn the screw in about 1 turn to keep it running and then lean it out. Lastly set the Idle speed adj. Do these in order or you will be chasing your tail. In circles. I have a collection of 2cycle outboards and some have mix knobs on the front right next to the choke. Makes it easy to dial the mix for day to day conditions. I use my runabout in Colorado and the different altitude lakes make a huge difference in the mix tuning.
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