Need help with timing 1987 90 inline 6

[turbinedoctor]

I have read http://forums.iboats.com/showthread.php?t=168855 and also have the manual. I have no problem going through the steps but my timing starts off at 5 degree ATC and when I go to adjust it, after I move past a certian point my spark drops out. I am using an inductive timing light. My trigger checks out ok, wiring is double checked. What would cause it to loose spark after coming slightly off on primary pick up? Is the some relationship between the stator position and the trigger. I am sure I have the stator back in the same position.

Forgot to mention, this is the first cranks after completing a rebuild and trying to set timing.

Durwood

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Is it possible that the spark is reduced when the timing is moved and the inductive timing light stopped flashing?

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

How much difference does it make if the stator is off by one mounting hole?

Durwood

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Called CDI tech support today and they advised that one hole off on these motors wont make that much difference. He did advised to check the White/Black wire from one switch box to the other, this might cause this type of problem.


Durwood

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

Called CDI tech support today and they advised that one hole off on these motors wont make that much difference. He did advised to check the White/Black wire from one switch box to the other, this might cause this type of problem.


Durwood

CDI also has an excellent troubleshooting page. The white black wire is a bias wire between the switch boxes. Did you set the timing pointer to the .464 position using a dial indicator in the no 1 bore? If the stator is off position the wires would not reach the switch boxes so it is unlikely that the stator is off. If you took apart the flywheel the timing indicator could be off.

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Thanks Dave, I did set pointer to .464, fly wheel was not taken apart and stator is in the original position. I did briefly check the bias wire and it appears to be correct. Still pondering ideas but it will most likely be Monday morning before I get back to it. I want to have time to look it over without distractions.

Keep the ideas coming.

Durwood

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

Thanks Dave, I did set pointer to .464, fly wheel was not taken apart and stator is in the original position. I did briefly check the bias wire and it appears to be correct. Still pondering ideas but it will most likely be Monday morning before I get back to it. I want to have time to look it over without distractions.

Keep the ideas coming.

Durwood

Durwood, it dawned on me that you checked with CDI re stator position so I assume it is a new CDI aftermarket stator. The wires are a bit longer than the original so it is possible to have it out of whack. I think it would be worth it to remove the flywheel again and rotate the stator counter clockwise one set of holes. Just thinking out loud here.

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Dave I replaced the stator and trigger about 1.5 years ago. When I did that project I took pictures and tie wrapped my wires to neaten them up. According to the wire tie and the pictures I have it where it was.

I dont have a picture of it now but this is when I first installed it.

Question/ What difference does it make where the stator is if the trigger is doing the firing? I am tring to figure out how it all works together.

Thanks for you input, keep them coming.

Durwood

 

[emckelvy]

Re: Need help with timing 1987 90 inline 6

Just a couple of quick thoughts in passing:

-Bend/flex the trigger wires while you've got spark, without moving the throttle arm. These wires are somewhat flimsy and I've seen busted trigger wires cause loss of spark when the wire harness flexes.

-Later model I-6's had a "Timing Stabilizer" installed. I don't know fer sur if one of those could cause this kind of problem but if you still have a timing stabilizer on your motor it'd be a good idea to remove it. Or at least disconnect it and see if there's any difference.

They are notorious for failing and when they do you can get an increase in spark advance which will melt the pistons. Most Inlines, unless they are completely worn out, need a stabilizer anyway. Do a search here and you'll see plenty info on this.

HTH..........ed

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Thanks for the input ED. I did read out the trigger coils and move the trigger forwards and backwards with the meter connected, no problems found. I do not have the Timing Stabilizer on this motor, it was disconnected before I bought it.

When I get time to mess with it again I will check each and every wire on the switch boxes again. Another thing I might try is to use a different cylinder plug and wire. I know the timing will not match the timing marks but I am courious as to if it will loose spark too.

Keep thinking and thanks for your input.

Durwood

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

Dave I replaced the stator and trigger about 1.5 years ago. When I did that project I took pictures and tie wrapped my wires to neaten them up. According to the wire tie and the pictures I have it where it was.

I dont have a picture of it now but this is when I first installed it.

Question/ What difference does it make where the stator is if the trigger is doing the firing? I am tring to figure out how it all works together.

Thanks for you input, keep them coming.

Durwood

Durwood, there is a relationship between the stator coils and the trigger. The field generated by the magnet passing the stator coil must charge the capacitor in the CDI box before the trigger discharges it..If the trigger is trying to discharge the cap through the spark coil before it is fully charged you will have a weak spark. As you advance the trigger further the spark will fail altogether since the magnet has not yet generated enough current to charge the capacitor.

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Dave I was thinking along those same lines and you have described what is happening. My timing is off by about 5 degrees and when I advance it I loose spark all together.

What I can't figure out is why. I put it back together the same as it was but now it does not want to work. Maybe I just think it is like it was. I need to back up and use an open mind.

In case you would like to look at my photos, here is a link to the current project "Rebuild" http://s87.photobucket.com/albums/k127/lmsgps1990/Boat/Motor%20Rebuild/

And here is a link to when the stator and trigger were first replaced.

http://s87.photobucket.com/albums/k127/lmsgps1990/Boat/Stator%20Change%20Out/


Thanks again for your input.

Durwood

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

I tried to look at your links to photobucket, however they are protected by pass word. I would be happy to have a look if you want to pm me the password.

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Dave, Sorry about that, I haven't tried that feature before. I just created a guest password, merc90.

Well I had sometime today to look at it and thought or hoped I found the problem. One of the bias wire screws was loose. After tightening that and rechecking my wiring for the third time I tried checking the timing again. Same results but this time I check all the plug wires. Plugs 2,4 6 have fire at idle and WOT. Plugs 1,3,5 only have it at idle, slightly above idle and it drops out.

Now that I have it down to only odd plugs I can start looking into switch boxes and stator correct?

I know these parts can go bad without warning, but what makes it so hard for me to think that one of them is bad is that it ran great before I took it all apart.

Still needing help and support.

Durwood

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

Dave, Sorry about that, I haven't tried that feature before. I just created a guest password, merc90.

Well I had sometime today to look at it and thought or hoped I found the problem. One of the bias wire screws was loose. After tightening that and rechecking my wiring for the third time I tried checking the timing again. Same results but this time I check all the plug wires. Plugs 2,4 6 have fire at idle and WOT. Plugs 1,3,5 only have it at idle, slightly above idle and it drops out.

Now that I have it down to only odd plugs I can start looking into switch boxes and stator correct?

I know these parts can go bad without warning, but what makes it so hard for me to think that one of them is bad is that it ran great before I took it all apart.

Still needing help and support.

Durwood

From CDI website:
MISS AT ANY RPM:
7. Rotate the stator one bolt hole in either direction and retest.


Notice step 7, even though it "shouldn't make a difference" being off one hole it sometimes does.
If the bias wire was loose one of the switchboxes could have popped, the only way to tell at this point is to swap them and see if the problem follows the switchbox. Its easy to mix up the wires on the switchboxes, make sure the correct color is on the correct terminal. Double check your grounds, make sure the ground wire for your stator is connected.
Thats all I can think of at the moment.

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Dave I am thinking the switch boxes are the problem so I will swap them first and retest. If that does not work then I will move the stator one hole.

Where do you find the best prices for switch boxes?

Where you able to get to my pictures?

Thanks for your help.

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

Dave I am thinking the switch boxes are the problem so I will swap them first and retest. If that does not work then I will move the stator one hole.

Where do you find the best prices for switch boxes?

Where you able to get to my pictures?

Thanks for your help.

Yup, got the pictures, nice documentation of the rebuild. I agree it is likely the switch boxes. I will ask around re switchbox pricing.

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

Yup, got the pictures, nice documentation of the rebuild. I agree it is likely the switch boxes. I will ask around re switchbox pricing.

Sent you a PM.

 

[turbinedoctor]

Re: Need help with timing 1987 90 inline 6

Well I swapped the stator wires and now all but #3 work correctly, #3 still fires at idle but drops above that. I was expecting the odd to work good and the even to act up.

 

[daveswaves]

Re: Need help with timing 1987 90 inline 6

Well I swapped the stator wires and now all but #3 work correctly, #3 still fires at idle but drops above that. I was expecting the odd to work good and the even to act up.

Well you've got me puzzled. ED, if you are following this , any thoughts?