First question concerns the behavior of the alternator on my 2002 9.9 4-cycle engine. Is the alternator charging at ALL speeds, including idle?I am seeing my voltage go up, but no indications onmy ammeter. My ammeter does show discharge when Iturn on lights, etc. The alternator is rated at max10 amps.Second question concerns hard starting. I had to have my carb jets cleaned this season because ofthe engine layup of over 2 years. I did run all the gas out, but didn't open the drain plug. My mechanic says I should drain the carb even if away from the boat for a week, or so. I noticed aftertwo weeks being idle, it was a bit reluctant to start. Using gasahol because that is all that isavailable. Would putting 'Stabil' in the gas tankhelp this problem? Any other measures I should take?
Stabil or SeaFoam are both excellent fuel treatments and should be used in every tank of fuel, even if it gets used frequently. SeaFoam in particular is an excellent fuel system cleaner as well as a conditioner. Odd that you have both an amp meter and a voltmeter. The alternator "voltage" may be slightly less than 12.6 volts at idle depending on whether or not you have accessories running. Likewise the amp meter will likely show slight discharge at idle depending on accessory load. Voltage should rise to 13.5 or more at 2000 RPM or higher. Depending on the scale on the amp meter (-10/0/+10), or(-20/0/+20) you probably won't see much deflection on the charge side due to the low output of the alternator. Since you have a 10 amp alternator, you will never see more than a 10Amp charge rate. But you could theoretically see a much higher discharge rate.
Originally posted by Upinsmoke: Stabil or SeaFoam are both excellent fuel treatments and should be used in every tank of fuel, even if it gets used frequently. SeaFoam in particular is an excellent fuel system cleaner as well as a conditioner. Odd that you have both an amp meter and a voltmeter. The alternator "voltage" may be slightly less than 12.6 volts at idle depending on whether or not you have accessories running. Likewise the amp meter will likely show slight discharge at idle depending on accessory load. Voltage should rise to 13.5 or more at 2000 RPM or higher. Depending on the scale on the amp meter (-10/0/+10), or(-20/0/+20) you probably won't see much deflection on the charge side due to the low output of the alternator. Since you have a 10 amp alternator, you will never see more than a 10Amp charge rate. But you could theoretically see a much higher discharge rate.
Originally posted by Upinsmoke: Stabil or SeaFoam are both excellent fuel treatments and should be used in every tank of fuel, even if it gets used frequently. SeaFoam in particular is an excellent fuel system cleaner as well as a conditioner. Odd that you have both an amp meter and a voltmeter. The alternator "voltage" may be slightly less than 12.6 volts at idle depending on whether or not you have accessories running. Likewise the amp meter will likely show slight discharge at idle depending on accessory load. Voltage should rise to 13.5 or more at 2000 RPM or higher. Depending on the scale on the amp meter (-10/0/+10), or(-20/0/+20) you probably won't see much deflection on the charge side due to the low output of the alternator. Since you have a 10 amp alternator, you will never see more than a 10Amp charge rate. But you could theoretically see a much higher discharge rate.
Sorry for the empty reply, but I'm not used to this forum yet. I have an ammeter and voltmeterboth because they tell me different things. WhenI had gel cells, I didn't want the voltage to climb too high to protect them, but now I use thevoltage to tell me the general condition of the batteries, like do they need a shore power charge.The ammeter tells me how much juice each device ispulling from the batteries, like is my vhf reallytransmitting. It is more indicative of usage thana voltmeter. The information I was seeking was more specific tohow many amps the alternator puts out for variousengine rmp, like idle, slow speed, half throtle.Also, at what approximate speed does the alternator begin to put out the maximum amperage.I think my ammeter is probably not reading correctly, but I have more checks to make, like doI have any fuses in the charging path.I don't see SeaFoam in my West catalog. West is the only marine store in my area. I am seeing things on the net that suggest even with Stabil, you should run the 4-stroke Yamahas at least onceevery two weeks to keep the carb from clogging up.
Your alternator will produce close to max voltage from 2000 rpm up. The amperage or current it delivers will mostly depend on the charge in the battery. The closer to fully charged, the less the current going in and vice versa. Depending on the sensitivity of your ammeter, you may not see much current in or out. A good voltmeter will show you voltage rise as you rev up or voltage drop as you throttle down or, with motor off, use your lights, radio, bilge pump etc.
Perhaps my post is a little light on detail. Unless one has a working knowledge of Ohm's Law it will all sound like crap. Voltage current and resistance are all related. Voltage is simply electrical pressure and while not always, it can be related to water pressure and an analogy can be made. If you have a lot of pressure (voltage), there is the potential for a large flow (Current = amps)but this depends on restrictions such as the diameter of a pipe (electrically, resistance). Voltage is also referred to as potential difference. This is important when different electrical sources are in a circuit, in your boat the alternator and the battery. If you have a flat battery the voltage that it holds will be like say 10 volts. Run your motor and the alternator produces say 14 volts, a potential difference of 4 volts leads to a considerable charging current. As the battery voltage or charge improves so the potential difference reduces and so the current(ammeter) reduces and more than likely the reading on your voltmeter increases. Introduce resistance between the alternator and the battery by way of say a bad or dirty terminal or earth voltage or pressure will be dropped across that resistance leaving less potential difference and less current and thus charge. This applies equally to motor off situations. Switch something on that has little resistance and you will have a large current flow... ammeter up and voltage meter down. Introduce poor connections or small guage wiring or bad earths to your anciliary equipment like lights radios etc because of those restrictions it is hard for the battery to push that power through (Small Pipe)and you will have voltage drop along the way resulting in low voltage available at your radio. While your ammeter will show little discharge and your volt meter slightly less reading there still may not be a good enough voltage to operate your equipment properly.Thus the higher the voltage or potential difference the greater the potential to produce electrical current. The higher the resistance, the less the current flow.So, poor connecions, dirty battery terminals, low level of battery acid, poor or corroded earths, light guage wiring and lack of maintenance are boaties worst enemies.I hope that helps.
Should this alternator be putting any amperage to the batteries (assuming they are not fully charged)when the engine is idling, or does the alternator only kick in at higher revs?
Once again, it depends on the potential difference. If your battery is very low, chances are that there may be sufficient voltage produced at idle to give some charge probably 1 or 2 amps, not enough to show on your amp guage. You said that you see the voltage go up on your volt meter. That indicates that the alternator voltage is higher than your battery voltage thus it is charging. Alternators unlike the old generators have the advantage in that they do produce a reasonable voltage at lower revs. Best charging will be achieved at 2000 rpm and better.
Just another thought to give you an example of alternator efficiency. Old cars had generators and when the motor idled, the red charging light would come on and go out when you increased revs. Modern cars with alternators only show the red light when the ignition is on and the motor is not running or when you have a problem. At idle, a healthy alternator will produce sufficient voltage to be greater than the battery voltage thus no red light.
OK, I feel like a complete idiot for not looking in the most obvious place for a solution to my ammeterproblem. I assumed that I had correctly wired my new engine alternator on my last cruise, when in effect I had bypassed the ammeter completely. I have since rewired it, and everything is showing properly on the ammeter.I have addressed the other problem of carburator blockage by using the SeaFoam which was not at my local Walmart, but at my local Murray Auto store.I am wondering if adding it to gas cans that werefilled a month ago will offer protection, or should I just pour it into my car's gas tank and get some fresh gas.
Alternator and Carb Questions 2002 Yamaha
I am seeing my voltage go up, but no indications on
Linear Mode
