Burning up stators

[Hotboat1]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" width="100%" UNSELECTABLE="on"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">I have a 89 225 Looper. I keep burning up Rapair stators. I'm on my third one and just melted another one this weekend. Also its taking out my power packs. I hear Rapair is the best in the biz but beginning to wonder. It seems when I put my stock stator on it runs fine. Could it be shorting some where?? I checked all grounds and all seems ok any help is appreciated!!!!!!!!!
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[gfinch]

Look for this. The windings will vibrate, if not encapsulated in epoxy, and then flex break. In my case the 12 volt charge coil(large wire) burned into the ignition charge coil(small wire) and then took out the power pack and then............. another is poor/loose connection at the terminal block. Poor connection in the battery circuit + and - . Bad battery.

[RUDERIOT]

Before this happens does the tach act weird- jump around, not work or stick?


As I have said before, the vast majority of O.M.C.s ignition problems are caused by the P.O.S. rectifier / regulator. Unhook it & wire in a Merc? stand alone rectifier. The one I used is silver & looks like a shot glass. Your alternator will charge wide open & if that bothers you put it on a switch or wire in a Merc 40 amp regulator. This was the cure for my ongoing electrical problems.

[Hotboat1]

Gary ........

Was the smoked piston in the pic's a result of your electrical problems??? Last year after burning one of the many stators I also had a smoked piston. Also, when you talk about terminal block do you mean the one on the rectifier.

[gfinch]

Hotboat!
Yes and yes. I was fishing a tournament and needed to run a 1/2 mile. Up till that point I had only idled around in a 5mph aera. When I took off it acted as though it was loaded up so I poked it a little harder and didn't make it where I wanted to go.
If RUDERIOT would post the part #s or applications I'd like to try that.

[RUDERIOT]

Gary ........

Was the smoked piston in the pic's a result of your electrical problems??? Last year after burning one of the many stators I also had a smoked piston. Also, when you talk about terminal block do you mean the one on the rectifier.

Yep, I bet so. When my last 4 drive coil stator shorted it made the motor "sound funny" & it would only turn about 7800 r.p.m.s. I put it on the trailer immediately & when the stator was inspected it was shorted. As a quick fiz I picked the windings apart & re-insulated the burned areas with shrink wrap: this worked until I took the system off & installed the Yamaha ignition.

I honestly believe that the cause of all of these problems is the rectifier / regulator shorting out & backfeeding D.C. current to where A.C. is (into the light coils & windings) thereby shorting them. The ignition will then "multifire" one or more plugs causing melted pistons or worse.

[RUDERIOT]

Hotboat!
Yes and yes. I was fishing a tournament and needed to run a 1/2 mile. Up till that point I had only idled around in a 5mph aera. When I took off it acted as though it was loaded up so I poked it a little harder and didn't make it where I wanted to go.
If RUDERIOT would post the part #s or applications I'd like to try that.

I wish I could tell you for sure what my parts came off of but if I was gonna do it again I'd p.m. Greynester see if he's got the set (rectifier & regulator) off of a 40 amp Merc fishin motor. These pieces are seperate & probobly as bullet proof as the Yamaha stuff seems to be....so far.

You don't want to use the same rectifier as I did anyway. I left fingerprints on mine when I touched it after 15 minutes of running. I didn't think that anything that got that hot could live.

[Hotboat1]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" UNSELECTABLE="on" width="100%"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">Does the Yamaha ignition (stator) bolt right on or is there a lot of mod's to be done. Also how much $$$ we looken at ???
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[RUDERIOT]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" UNSELECTABLE="on" width="100%"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">Does the Yamaha ignition (stator) bolt right on or is there a lot of mod's to be done. Also how much $$$ we looken at ???
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Oh Good Heavens no. None of it bolts right on. If it did nobody would fool with the omc ignition. To be completely fair, my old system & one that a buddy of mine owns will let the motors turn 8500+ & I believe his uses all stock parts with the limmiters cut out of the boxes. Mine used a Rapair 4 driver stator.
As for the cost it depends on your access to a donor motor for the hardware & if you can do the retrofit yourself. You'll need to have the taper in the flywheel hub changed as the existing one is metric & the easy way to mount the stator is to buy a custom upper bearing head with the proper height & spaced towers for the Yamaha stator from Wayne Taylor. If all else fails I'll have mine for sale this fall.:D A COMPLETE bolt it on and go system is worth around $1,000.

[Hotboat1]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" width="100%" UNSELECTABLE="on"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">8500 rpm's from a OMC looper!!!!!!!!!!Is that with the Yamaha or the stock ignition.</TD></TR><TR UNSELECTABLE="on" hb_tag="1"><TD style="FONT-SIZE: 1pt" height=1 UNSELECTABLE="on">
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[j_martin]

You don't want to use the same rectifier as I did anyway. I left fingerprints on mine when I touched it after 15 minutes of running. I didn't thing that anything that got that hot could live.

Silicon electronics often runs near the boiling point, on either side.

We used to warn new techs that to touch the 486 processor after an hour of math co-processing stress testing is to lose some skin. Most touched them anyway just to see for themselves.

[RUDERIOT]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" width="100%" UNSELECTABLE="on"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">8500 rpm's from a OMC looper!!!!!!!!!!Is that with the Yamaha or the stock ignition.</TD></TR><TR UNSELECTABLE="on" hb_tag="1"><TD style="FONT-SIZE: 1pt" height=1 UNSELECTABLE="on">
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Like I said, 'Gator uses all stock parts with the limmiters cut out, if I remember right & I had Rapair build me a stator with 4 drive coils on it. This drastically increases the primary output voltage to the coils, wich the stock system is sorely lacking. This was done with the old 2 box ignition on wich the limmiters can't be just unpluged.

I only gained about 200 r.p.m.s with the Yammi stuff but I think I'm at the end of the porting in that block.

[jphii]

A COMPLETE bolt it on and go system is worth around $1,000.

I think it is worth more than that considering the work involved. I've got an exra system including the cut top cap but without the flywheel (but it may be coming soon) that only needs wired to the OMC harness. If you try and buy a real, complete "bolt on" system it will set you back way more than a grand.

[Jeff_G]

Through this thread I don't see any explanation as to why the RAPAIR stators were burning up and secondly why or how they could possibly cause a piston to let go.
The alternator coils are independent of the charge coils. Now if the alternator coils do overheat it can affect the charge coils. But voltage is voltage. With the proper stator putting out the proper voltage it should not do anything to the power packs or switchboxes. That being said the faster you turn the motor the more voltage produced. Mercury uses a shunt system on some motors to drain excessive voltage. As RAPAIR/CDI does.
The voltage going to the power pack from the stator is pretty constant and does not go directly to the coils. It is stored in the pack until the trigger coils send a voltage to the pack and tell the pack to release to the coils. So the timing is totally controlled by the triggering coils and scr's inside the pack. Now if the pack was bad I could see where a cylinder or pack could double fire. This should show up immediately so "clearing out" the motor made the problem worse. Your RPM will tell the tale.
But here again the stators were not the fault but the pack was.
So for the guy that has blown some pistons and blamed them on the stator I would be looking at the packs first. Rectifier/regulator second and stator last. The stator is the result of the problem, probably not the cause. With a properly set up system with good working components, none of this will happen. Unfortunately some components aren't worth the metal and silicon they are made from.

[RUDERIOT]

All I can do is tell you what I've observed durring the 15+ years I've been messing with hotrod Loopers.
When this all started in about 1992 I had an Evolution Stage III fingerported bigbore bridgeport with "factory" /second effort 8600 r.p.m. boxes on it. The motor would only turn 6300 so I closed the plug gaps to.020'' & it gained about 600 r.p.m.s. I called Marvin at Evolution & he told me about the Rapair 4 driver stator. With this adddition & no other changes it then turned 7600. The stock stator had checked within spec. & looked o.k. The only varriable here is the amount of secondary voltage arriving at the plugs & the plug gap. As we all know, as the gap increases so does the secondary voltage requirement. Increases in the secondary can only come from one place, the primary output of the stator.

[Jeff_G]

The voltage from the stator is sent to the power pack, all voltage from the charge coils is stored in the power pack. The voltage is released from the capacitors in the pack via a electrical signal from the trigger. The voltage from the power pack is then sent to the coils which step up the voltage to fire the spark plugs. The closing down of the electrode on the spark plug does not increase or decrease the voltage at the plug. It changes the timing and duration of the spark. It does take more voltage to fire a larger gap, but for our purposes the voltage is the same. At no time does the voltage from the stator go directly to the coils or spark plugs.
Differences in both the charge coils and alternator coils of a stator can have an effect on the motor rpm by reducing or increasing the drag on the flywheel. Less coils or differences in windings can equal less drag.
For example if I were running Champboat for qualifying I may run a stator for a carburated motor, 16 amp. Less winding/voltage = less drag. But during the race I would need the increased voltage output to keep the EFI system running, 40 amp. Even though there is a small loss of HP due to coil drag. Same with drag boats.
It isn't the change of voltage from the stator that causes rpm changes unless the stator just isn't putting out enough. Consequently only the flywheel position in relationship to the trigger coils and the operation of the power pack, and spark gap are the only things that can change the timing. Leaving out advance modules, quickstart systems etc.
So you can see a bad stator can not cause detonation of a piston. A pack can, a trigger can and a bad flywheel can.

[RUDERIOT]

If we knew that the stock stator drive coils were "filling" the capacitors I would agree with you. They have a speciffic value & will only hold so much.


Read the specs for secondary voltage in the service manual. As I remember its a range of 20-35,000. Thats fine for a fishin' motor but 20,000 will not fire the plugs reliably at increased r.p.m. & compression levels.
All I can tell you is what I have seen work.

[Jeff_G]

Secondary voltage on almost any V-6 up to around 40K. I was just telling you why a stator doesn't cause piston failure and what could in the ignition system.

[Hotboat1]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" width="100%" UNSELECTABLE="on"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">So, should I have Rapair build me 4 driver stator. Also I noticed the windings used in Rapair coils were smaller then the stock stator...
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[racer]

A stator with week output will keep an engine from reving but it will not burn a piston.

If you are having problems burning the alt side I would check the battery and if you are running an optima change it to a lead acid vented battery, the system does not like these batteries and we have recieved several service bulletins about this.

By the way I have seen many loopers turn over 9k with factory ignition and still be making power another words not gained because load removed.

As for power it takes to turn the alt, I have a way to turn off the regulator on my dyno and it takes 7hp to turn a 35 amp system over 6k.

[RUDERIOT]

That worked for me. But like I said, I think all the problems start in the rectifier/regulator.

[RUDERIOT]

<TABLE id=HB_Mail_Container height="100%" cellSpacing=0 cellPadding=0 width="100%" border=0 UNSELECTABLE="on"><TBODY><TR height="100%" width="100%" UNSELECTABLE="on"><TD id=HB_Focus_Element vAlign=top width="100%" background="" height=250 UNSELECTABLE="off">So, should I have Rapair build me 4 driver stator. Also I noticed the windings used in Rapair coils were smaller then the stock stator...
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I defer to the master. I was typing at the same time Racer was. Listen to him, do exactly what he says & you'll be fine.

[Jeff_G]

What am I chopped liver? :D

[J.P.]

If you know your stator is good. How much primary voltage to the ignition coil does it take to make the ignition coil generate 40k volts to the spark plug. I checked my single power pak and it varies from 500 to 100 volts to the ignition coils. Also the plug gap on a single pak calls for 30 thousandths and the 2 pak call for 40thousandths gap. I would think the 2 paks produce greater voltage.
Thanks
Joel

[RUDERIOT]

If you know your stator is good. How much primary voltage to the ignition coil does it take to make the ignition coil generate 40k volts to the spark plug. I checked my single power pak and it varies from 500 to 100 volts to the ignition coils. Also the plug gap on a single pak calls for 30 thousandths and the 2 pak call for 40thousandths gap. I would think the 2 paks produce greater voltage.


Thanks
Joel


That's interesting. I never checked the primary, I just took Evolutions' (Marv)s' word for what was needed & Rapairs' word that they built it for me.

A coil is nothing but a step up transformer at about 100x value so if you want 40,000 secondary you would need about 400 primary.

Do you mean it varies that much coil to coil at a given r.p.m? I believe you but I don't understand how that's possible.

[J.P.]

At cranking rpm.

[J.P.]

Ok thats what I was looking for,..so 400 primary input is where i want to be in order to get maximum out to the spark plug with good ignition coils.

[cocacola]

is there a thread on what a stator does and symptoms of one going bad?
still kind of a newbie and wanting to learn....

[RUDERIOT]

Ok thats what I was looking for,..so 400 primary input is where i want to be in order to get maximum out to the spark plug with good ignition coils.

Yeah that would be ideal. My 4 drive coil Rapair stator is only supposed to make 375 as I remember.

The easy fix for low voltage ay the plugs would be a set of coils that are 150x. But then low ampreage would probably be a problem.

Hell, I guess ya could put 6 drivers on it.......:D

[RUDERIOT]

This is how bad it has gotten.... Before I finally bit the bullet & put the Yamaha ignition on it I spent quite a bit of time thinking about alternative ignitions I could graft onto it. The best 2 involved #1- a 6 cylinder Vertex or some such Magneto hung on a bracket upside down & ran with a cog belt. It wouldn't work cuz if the motor turned 9000 the mag would have thought it was turning 18000 since it would have to run at crank speed instead of half crank with a 4 stroke. I did a fair amount of looking for a 12 cylinder mag like off an Allison aircraft 1710 but kinda gave up when I realized I would need 2 plug heads. Other than that it would have probably worked if you ran the mag half crank speed & set it up as 2 six cylinder firing orders. The other problem was that the thing might have been the size of a paint bucket. #2- This one was a natural....use the stator to make the primary & feed it to 6 old '70s era Mopar ignition boxes & use the stock timer base to trigger them. The "chrome" box was a high voltage piece & would let the car motor turn over 7000 so with 6 of 'em there would have been plenty of dwell time for a 9000 r.p.m. 2 stroke. Since I could never find out the specs & had no idea at all if a stator could be built to supply 6 of 'em at a time I gave up on this as well.

[J.P.]

I was reading in my 3.6 manual and its says 300(VAC) primary to ignition coil for max ignition coil secondary of 40k volts. I there a part number for the Rapar 4 drive coil stator.