Replacing stator and tuneup

[llyons]

Hi, I am fixing to replace a stator. I had a couple questions related to this that I am hoping somebody can answer.

- Is there any markings that I need to do on stator or housing to make sure I put the next stator on proper and its able to start? I did mark the stator screws relative to the wiring output.
- after replacing the stator, do I need to adjust and timings or should I be good to go with the previous timing.
- I am planning on disconnecting the low speed and high speed spark advance (idle stabilizers) permanently. I have read where this is the right thing to do. Do I have to do anything else when I disconnect these..or just tape up the leads so they dont make contact and good to go?

 

[tommarvin]

Have you tested the stator with a multi meter or any other way To make sure its bad, nothing worse than buying a expensive ignition part and it does nothing to fix the problem. Check youtube and CDI electronics.com for testing procedures.
You should remove flywheel to look for burn marks on the stator top and bottom then the wires.first then test it.
I would not disconnect anything that Mercury designed for the motor.
What year, make hp, model is this motor?
What makes you think it the stator, test the trigger too.
Do you have a malfunction indicator light to check error/trouble codes, or another way to test codes?

 

[Babbs]

If you will not repair it, I suggest you buy new ones https://goo.gl/X85B7Q .

 

[llyons]

I tested the stator impedance and they where out of spec. I also tested peak volts ac or DVA and those where low around 60vac on one side and 120vac on the other. So I purchased a new stator and 2 new switchpacks.

My big question is more or less can I just replace the stator an switchpacks and the motor should fire up or do I need to recheck and set timings?

 

[Chris1956]

Gee, it is very easy to check idle pickup and max spark advance. Why not do it for piece of main, and to rule out that you messed something up?

 

[llyons]

In some other sites it says to just leave the low and high spark advance off or disconnected (idle stablelizers).. The only other thing I see in the service manual is tuning and that involves #1 cylinder TDC and move the engine .462 in, etc.

Am I right to think that I can fire up the motor after replacing the stator and switch packs and that timing/tuneup is still set from before?

 

[llyons]

I guess what I am asking is that after the stator is replaced do I need to adjust the following.

- timing pointer adjustment
- idle stop screw adjustment
- timing adjustment
- throttle primary pickup
- max spark advance
- idle rpm


-

 

[Chris1956]

As I said, it is pretty easy to check the idle pickup and mas spark advance. If they are correct, everything else should be fine.

You will need to set/check the timing pointer. So remove all spark plugs and prop and set the motor to TDC. Measure the distance from the top of piston #1 to the top of cylinder head. Add .464 inches to that measurement and rotate the flywheel until that measurement is achieved. Check or set timing pointer.

Now install #1 spark plug into motor, and install timing light. Advance throttle in gear until carbs are set to open, but still closed. Jumper starter. ignition on, and read timing value, Compare to idle pickup spec for your motor.

Now advance throttle to full and read timing as before.

If timing values are correct, you are done.....if not, a link and synch is in your future.

Most motors have idle stabilizers. Those need to be disconnected for the timing test. Most leave them disconnected. Do you have other timing control electronics?

 

[llyons]

Thanks for the info. Even though I have the service manual having the procedure independently confirmed helps.

I have an idle stablelizer (plugs into the Bias circuit) and a high speed spark advance (plugs in on one trigger terminal).

When you say idle pickup is that the same as the throttle primary pickup or the idle stop screw adjustment (going on service manual terms)

 

[Chris1956]

Yes, Idle pickup timing is the same as primary pickup. I guess it is an older term for it.

 

[llyons]

I just finished putting the new stator back on in the same orientation. I changed out the 2 switch packs with newer switch packs. So stator and both switch packs are new. We started it up to see if it would fire up and run and it did. It ran fine for a minute or two then the RPMs dropped. When I gave it a little more throttle it picked up and ran normal. I decided to put a timing light on the spark plugs to make sure they where all firing. What I noticed is when the motor is running fine, all the spark plugs are firing with a good repetitive frequency. When the motor would suddenly start running at much lower rpm I noticed the spark plugs on the 2,4,6 side where all firing well although the frequency was less.. On 1,3,5 side the firing became eratic and sometimes no fire. When we gave it very small amounts of throttle just to bump up the rpms, all the cyclinders would fire like they should.

What might cause the engine to lower in RPM (probably 1,3,5 cutting out) but adding a little throttle brought them all back in? The idle stabilizer and high speed spark advance where both disconnected during this experiment.

Going to work through checking the timing, checking the throttle primary pickup and max spark advance next. Have a long 2 week trip to Nashville and Missouri so it will be a couple week before i get back on this.

Here is a video that shows what the motor is doing. https://youtu.be/mhPz3F5Zask

 

[Faztbullet]

So remove all spark plugs and prop and set the motor to TDC. Measure the distance from the top of piston #1 to the top of cylinder head. Add .464 inches to that measurement and rotate the flywheel until that measurement is achieved. Check or set timing pointer

This is incorrect!!!! Remove plugs, install indicator and bring to TDC, ZERO indicator and back off .464 and set pointer ...no math involved.

 

[Chris1956]

Fazt, That only works, if you have a dial indicator. I use a caliper, accurate to .001", but I need to add numbers to make it work.

Good thing I are college edumicated

 

[llyons]

Finally got the motor working well again. Took it out today and it started up right away ever time and actually seemed to have a bit more power than before.

After replacing the stator and 2 switchpacks, we still had one side not firing properly. We couldnt even do the timing tests because #1 didnt register any spark. We replace the switch pack on that side with an older switch pack and got spark on both sides and where able to continue the timing sets. Brand new switch pack was bad.

We did adjust the throttle primary pickup to 11 deg. ATDC and the Max Spark Advance to 22 btdc. They where set to 16 ATDC and 18 BTDC before.

Boat was running great, starting on a little key turn, better than ever before it seems. Now I just need to tighten up the hydraulic steering.

Thanks everybody for helping point me in the right direction.