Stator function question

JZEVINRUDE

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Apr 28, 2009
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What is the function of a stator and what are the consequences of it not performing properly?
 

jay_merrill

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Re: Stator function question

In combination with the magnets in your flywheel, its an alternator. It produces alternating current, which is then converted to direct current by your rectifier.

Since the stator produces the current used to power both the ignition system and the charge system in your motor, if the stator is not functioning, your motor won't run. If it won't run, obviously it won't charge anything either.
 

JZEVINRUDE

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Re: Stator function question

does the stator produce the current for the coils? If so is there a possibility of it producing a diminishing current as it gets older?
 

jay_merrill

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Re: Stator function question

Yes, the stator produces the voltage that is used by the ignition coils. The charge coils in the stator, produce the AC voltage that is converted to DC voltage and then routed to the appropriate ignition coil, by the power pack.

There is typically an output test that can be performed to check the condition of the charge coils. There is also an ohms test that can be performed. I am far from an expert in electronics, but I would say, yes, charge coils can gradually lose output over time and use. My take on it is that as resistance increases, effectiveness decreases. Once again, however, that is a "hacker's" understanding of the situation. A charge coil can also short completely, which will be indicated by a zero reading when doing an ohms test.

That said, my experience with stators suggests that they either work well enough, or not at all. Generally, a situation where less than all of the cylinders in the engine are experiencing misfiring due to ignition problems, is caused by problems with the power pack, one or more ignition coils, high tension leads, etc. When the motor won't run at all due to ignition problems, the stator is often the culprit. Bear in mind though, that there are other issues that can be in play.

BTW, if you have a specific problem with your engine that you are trying to solve, the best way to get help in troubleshooting it, is to simply describe it here. Start with the make, year and model of your motor and then describe the problem.
 

clanton

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Jul 9, 2001
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4,876
Re: Stator function question

On one of your other post. The test of removing the sparkplug wire is not a good or recommended test. There is a service bulletin or old info letter from OMC in regards to this test. If this is the 1978 70 HP your problem could be caused by low crankcase pressure or the carbs, carbs were changed by service bulletin, some of this info in in the Cylmer manuals. Easy test for ignition is check voltage at ignition coil primary wire, engine running. Meter on ac scale 300/400 volts, X the results by 1.414 should be close to spec. The 3 primary wires should be the same voltage.
 
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JZEVINRUDE

Seaman Apprentice
Joined
Apr 28, 2009
Messages
30
Re: Stator function question

How do I test for low crankcase pressure and is the #1 plug the primary coil wire? When you talk about the carbs being changed by a service bulletin are we suggesting that the carbs are entirely replaced?
 

Rob Downs

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Apr 30, 2009
Messages
2
Re: Stator function question

Hi I am Rob,
I have a problem with a johnson88.I have a boat that was tooling down the lake just fine.Its rpm increeased for about 30 seconds and the motor died. I thought it was fuel delivery but all cylinders are wet.no spark.Is it the stater?I wondered about the house wiring but have not checked that yet because of what I saw,high rpm and then death.I am thinking flywheel key,stator,or house wiring.Where do I start?
Rob
 

Rob Downs

Recruit
Joined
Apr 30, 2009
Messages
2
Re: Stator function question

Hi I am Rob,
I have a problem with a johnson88.I have a boat that was tooling down the lake just fine.Its rpm increeased for about 30 seconds and the motor died. I thought it was fuel delivery but all cylinders are wet.no spark.Is it the stater?I wondered about the house wiring but have not checked that yet because of what I saw,high rpm and then death.I am thinking flywheel key,stator,or house wiring.Where do I start?
Rob
565555r4
 

jay_merrill

Vice Admiral
Joined
Dec 5, 2007
Messages
5,653
Re: Stator function question

Rob, you have hijacked someone else's thread - the best place to start is to post your own thread. Describe the make, model and year of your engine and then describe the symptoms your are experiencing.

Welcome to iboats!
 

bigpoppakdog

Chief Petty Officer
Joined
Jul 9, 2008
Messages
437
Re: Stator function question

depending on the year of the motor, the motor will run without a stator. Your battery won't get re-charged though.
 
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