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To everyone with RPM issues motor wont rev

"Guys there are a few of you o

"Guys there are a few of you on here with the same problems who have gone down the same road and are hitting the same wall. We must remember that it takes three things to make an engine run, fuel-compression-and ignition. Yet, I keep seeing so many people spending a lot of time and money on just one, the fuel side, of these three. I believe it's because it is the one that we feel most comfortable dinking around with.

The truth is that if you confirm that your fuel pumps are working and that you don't have containments in the fuel then it’s time to stop dinking with the carbs and start looking elsewhere. I read an SAE report that stated nearly 35% of all ignition problems where misdiagnosed has fuel delivery issues. Yet, only 7% of ignition problems where misdiagnosed as fuel problems.

Starting in the early 80s all major outboard engine manufacturers switched to CDI ignition systems. They did this for two reasons; the first is that it is a more precise system and wont jump around at high rpms. The second is because simple diodes and switches can control the system.

With this in mind when you have an issue where the engine just stops at an rpm level and refuses to go on we can usually move beyond the carbs rather quickly. Every manufacturer has a way of working around the CDI but each of these is different. You need to get a manual to find out just how your manufacturer does this. Once you have ruled out the controller then it’s time to rule out the fail-safes. In general these include the oil injection and high temps fail-safe limiters. Once again you’ll need a manual to learn how to test these fail-safes.

Once you got those out of the way it’s time to look at where you get your from, the coils, stator and rotor. It’s highly uncommon for coils to up chuck and/or limit your RPM levels. If a coil is going bad it’s going to cause problems throughout the RPM range. On the other hand, on engines equipped with a CDI, there are two stages of power beginning delivered to the coils, a low side and a high side. If your engine is missing below 2000-2800 rpms but flies from 3K till max rpm then your low side is probably the problem. If your engine runs up to 2000-3000 but then falls flat on it nose (and you don’t have a limiter issue) then the high side is probably going out. The only way I know of to test a stator is to use an ohmmeter and start looking for a short but this method doesn’t always work. The best true method is to test the unit with a known good unit."
 
better to test in volts

ohm


better to test in volts

ohms are so 80's method of testing
ohms are only good for insulation breakdown
 
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