Continuity from tip to shaft on Mercury 1115

Good morning,

I am trying to trace down some stray voltage. I am starting to think the culprit is the rotor. how much continuity should be from the tip of the rotor to the shaft? I am getting a very little, but I would think there shouldn't be any at all.

Here is the link to my previous post:
http://www.marineengine.com/boat-fo...50SS-Still-having-electrical-problems-trouble

It runs well with a bit of a rough idle. I am also getting a very small spark every time I adjust the carbs which jumps to the screwdriver. The screwdriver is grounded through the hole on the front plate and as it comes into contact with the idle adjustment screw a small spark jumps.

Thank you,
Matt Chonka

Sorry, I was in a bit of a hurry earlier. Let me clarify a few things.
This is a 1967 Mercury 950 SS with serial number: 2100114 and it is mounted on a 1965 Lone-star aluminum hull. I am running a distributor and flywheel from a 1974 Mercury 1115 serial Number 3945266. The timing is dead on and runs very well at WOT. The idle is a little rough but manageable.
Here are things I have done or replaced over the last two years for one reason or another:
New CDI, stator, control box, coil, trigger coil, regulator
Rebuilt carbs and rechecked several times
New reeds
Upper and lower engine seals
Replaced all gaskets
Lower unit gone through and water pump rebuilt
New batteries
New ignition switch
New kill switch
New plugs and wires
The distributor cap looks fine (not positive, but looks new), no evidence of cracks. Started engine at night without the engine cover. No Sparks jumping anywhere. I am still getting an erratic voltage from everywhere on the engine block and at the battery. I have used different meters with a DVA adaptor and the same thing happens. With the meter in VDC, if I touch just one probe to the engine block (or just about anywhere the meter goes crazy and will shut down. The other probe is dangling.
Now I noticed the when I go to adjust the carbs and the screwdriver just touches the idle adjustment screw I can see a little spark (all three carbs). Since the screwdriver goes through the front cover support hole, it is ground there as it goes through. Not sure which side is energized.
My opinion is that the voltage leak is on the high voltage side of the coil. To make a meter switch back and forth from DC to AC then shut down, it has to be a lot of voltage and alternating.
I am looking at the rotor as a suspect. I get just the slightest continuity through the shaft of the rotor to the tip (mind you, this is a mercury 1115 rotor). The resistance reading is 30.xxxM ohms and sometimes will not read at all.
Please ask your questions, I will let you know if I have done it, will do it or replaced it. All comments and suggestions are welcome. I need a fresh mind to think this one out.
Thank you,
Matt Chonka

The engine is grounded to the neg. battery post.

Just in case there is any confusion, this only happens when it is running.

On the Merc CDI systems, they run a lot of ground straps which I bet you don't have. The extremely high voltage is finding a path other than where it's supposed to go. If the rotor were truly grounded from the contact to shaft, it would cause a miss in the ign or no spark at all.

The fact that you get sparks from the front cowling to the carbs (and you're lucky it didn't blow up!), shows that the cowlings are not at ground plane.

The rubber cowling mounts effectively isolate the cowls, so you need to run a ground strap from the top of each rubber mounts' stud, to the bottom.

Then remove the "horse shoe" trim collar below the large lower cowling. Take out one of the stainless screws that hold the rubber gasket down there in place, and run a ground strap up to the bottom of the lower cowling (which is how Merc did it), or just run the wires longer and tie them into the same point where the big Negative internal wiring harness cable mounts on the lower cowl. Run at least 1 strap on each side. Merc installed (4) ground straps down there, (2) in the front and (2) in the back.

And then just for extra measure, you could run another ground strap from the lower cowl to the engine block. Any convenient bolt on the block will do, but I wouldn't recommend undoing any of the crankcase or exhaust manifold bolts. A starter mounting bolt would work just fine.

I bet your "sparking carbs" problem will go away and you may find it runs better.

HTH.........ed

Also install a ground from boat transom to - side of battery

Ed-Mc and faztbullet,

Thank you for the replies. I do have some of the grounds you talk about, but not all. Give me a few days and I'll get it done and post my findings.

faztbullet said:

Also install a ground from boat transom to - side of battery

Click to expand...

Yeah, since the boat's aluminum that's a good point. Not so much an issue on a non-conductive wood or fiberglass boat!!

Ok, I have installed ground straps in all the places that you mentioned and a few more. The neg. side of both batteries are tied into an isolated grounding bar. Then a grounding strap from the bar to the to the transom.
Once started the motor, I noticed it ran a little smoother and I can now use my meter to get some readings without it going crazy. However, I am still getting the tiny spark when touching the carbs with a screwdriver and the brand new regulator must have shorted. It is noticeably a smaller spark, but still a spark. I plan on grounding each carburetor to the front cowling, along with another ground from the block to the big Neg wire on the distributor side and see if this takes care of the sparking.I do not remember seeing a spark like this when it was a point set system. So when I swapped it out to all CDI, I should have installed grounds everywhere?
I am well versed in AC/DC electrical systems and have read up on boat wiring systems. For the most part, I fully understand, but I have read a lot of controversy about bonding an aluminum hull or not. It makes sense to me that if the outboard is going the be mounted to the transom anyway, it may as well be hard wired to the ground plane.
I will update tomorrow and let yall know if I get the sparking to stop.


Thank you both for the advice,
Matt

Maybe a ground from the front cowling support to the lower cowling would help. You'd think those 2 parts would be grounded together well enough, but apparently just being bolted together ain't doing it. Very strange, indeed. Be sure to scrap any paint away at the grounding point, so those ground straps have clean metal to bite into.

Just another thought, a big ground strap from the front cowling support to the engine block should do it. The carbs are bolted directly to the block, so they and the block should be on the same ground plane.

And one more brain cell clicked, be sure you have a ground strap from the grounding point on the distributor body, to the block. That one's definitely gotta be there.

You talk about cantankerous, this motor is not going to cooperate without a fight.

I have installed more grounding straps from the front crowling to the bottom crowling and to the block. I installed another ground from the distributor housing to a different location on the block. I was still getting tiny sparks at the Carb adjusting screw. So I installed a strap from the front crowling to the bottom carb mounting bolt. I now have no sparks on the bottom or top carb, but middle carb still has very tiny sparks. I do agree that the carbs should be on the same ground plan as the block, they are bolted directly to it. I'm stumped on this one. I have never seen and engine so ground deprived.

I also spoke a little prematurely in an early post. My meter still shuts down (after flipping out) when I touch the block, but now it does it when both leads (before it was just one lead) are touching the block. I can touch one and it seems fine.

Tomorrow, I plan on grounding the bolt on the middle carb and switching back to the original regulator. It seems I have trouble with theses little CDI regulators. It is probably my grounding issue (keeps blowing them or grounding them out).


I will update tomorrow evening.
Thank you,
Matt

Hi-Voltage does strange things!!!!

https://www.youtube.com/watch?v=UF5EDV6T7es

Here is where I am on this outboard.
I have grounded just about everywhere. I have added ten grounding straps. My meters do not go crazy anymore and the sparking stopped, I started it at night and saw no sparks with the screwdriver.
So, now I began checking voltages. I started at the battery with the engine running at 1500rpm:

At battery terminals: 12.35vdc
At regulator Positive terminal and engine ground: 12.35vdc
Across inputs from stator on regulator: .010vac
Across one stator input and ground: .010vac
Across the other stator input and ground: .010vac
disconnected the two stator wires and tested across: .010vac

So it seems the stator is not producing AC voltage. The Stator bench tests well within Specs and the Tach is working better than it every has, but no AC output.
The Stator is brand new, CDI electronics p/n174-4793. This is a 10 coil stator the original is a 12 coil and the flywheel is a 12 magnet flywheel. I went back to the old flywheel(this was just wishful thinking). Both flywheels are in good condition ( no cracks and all Magnets work). Changed the new stator out for an older stator, using both flywheels. All this has yielded the same results.

So here are my thoughts/questions.

-Am I still having a high voltage issue and somehow is it robbing the voltage from the stator and grounding it?
-Are both stators bad? If so both bench test great and operate the tach great (I just have to adjust the tach setting when I go back and forth 10coil to 12coil)
- CDI electronics state the 174-4793 is a direct replacement for this outboard even though the original was a 12 coil. This should just result in lower amp stator.
- Is it possible the high voltage issue I had reversed some of the magnets on the flywheel and this is effecting the electromagnetic field and its production of electricity?

I still think am missing something. Is there any other test I can perform?

For now, this is all I can think of, my brain is hurting from all this.

Thank you
Matt

I would suggest that there's something wrong with your measuring device. Maybe the meter has been damaged by the hi-voltage stray electricity.

The fact that your tach works suggests that the stator is putting out AC voltage and the rectifier is working as well. When the rectifier is bad, the tach won't work.

Unless you have your tach sensing wire connected to the switchbox, and then it won't matter what the condition of the charging circuit is, either. But that switchbox tach output was only meant for OEM "SS" tachs and aftermarket tachs won't operate correctly. I'm assuming you have the tach wire connected to one of the "AC" terminals on the rectifier where the yellow stator wires connect.

BTW do you have a bridge rectifier installed or a voltage regulator. The original rectifer used with these old Mercs was just that, a rectifier and it did not regulate.

Definitely need to know, since if you do have a voltage regulator installed and it's not regulating properly, you may get voltage and tach output but not rising voltage.

And I still haven't wrapped my head around how you're using a 1150 flywheel on a 950, the 950 has a tapered crankshaft and the 1150 has a splined crankshaft with one blank tooth for proper keying. No way to interchange these, unless you've put a 950 hub on the 1150 flywheel. And there's no real reason to do so, since the 950 flywheel would have absolutely no effect on the CDI system you've retrofitted to your motor.

Anyway, I think we just need to get on the same page and then maybe we can scratch our heads and figure out what's going on with your "Frankenmerc".

Cheers........edView attachment 13814

Sorry, I was using some bad and sloppy terminology.

I am running a Rectifier (CDI Electronics- Mercury / Mariner Rectifier: 154-6770)


Tach is running off one AC post of Rectifier. I agree with you about the Tach, if it is working I should be getting AC current.
Yes, the original is a Rectifier:



The flywheel was a long shot that I took and I wanted to see if they would interchange. Since the stator and Rectifier were new and both bench tested fine I just wanted to eliminate any possibility of the magnets being bad (even though each magnet seemed to work individually, I do not have a Gauss meter to verify). I know it was a shot in the dark, but I have seen stranger things happen in autos. I did swap hubs to make the 1115 flywheel work. The 950 flywheel is back on.

Both meters I have been using work everywhere else, AC outlet, 12volt battery, resistance/continuity checks.... and with almost identically readings. I am going to use a 3rd to back up my readings of the other two.
Going out now to do a little more testing.
Thank you,
Matt

I was still not happy with the grounding situation, so I cleaned and scraped the areas where the cowlings all touch. I did this because once in a while my meter would still just shut down (this is after it would blink and it would do it to different meters). I am getting an AC and DC voltage now and haven't had the meter blink off.
Ed-MC, I do think you are right about one of the metering devices being bad. The DVA adapter seems to be the common factor and every time I used it with any meter I got no reading. So, now without the DVA I get an AC voltage of around 14.00vac across both stator inputs at the rectifier and about 7.12vac from either input to ground. On the DC output side, I get about 13.07vdc and at the battery its about 13.00vdc. To me, this is on the low side, but I do realize that this is a stator and rectifier, not an alternator. I am also not running it at high rpm's. The tach is smooth and steady. I took these readings with the engine running at 1500rpm.
I will be taking it out on the water Thursday and will check the charging system at higher rpm's.
I will update when I get back.
Thank you,
Matt

I think you may have 'er whipped! Also note that the DVA is normally used to measure cyclic high-voltages coming off the CDI box and other outputs, normally you wouldn't need it to measure the charging output. Definitely not for battery DC voltage, I don't know if it would even work that way. Anyway, looks like you got 'er figured out, no more sparks and power from the charging system, ready for Sea Trials! Bon Voyage.......ed

Took it out today. I thought it was going to be a bust when I could not get it about 2000rpm, but did a quick adjustment of the timing and it came to life. Checked the voltage at the battery when at WOT--16.30vdc. Ran smooth for the most part, but still having idling issues. When returning to neutral from either reverse or forward it will die. I am trying to keep the idle rpm's down below 1000, but it just doesn't like it down there. I will keep adjusting till I get it closer.

Thank you for all your help, I really a appreciate it.

Matt

The old Inlines are pretty sensitive to idle mixture. Since these carbs don't have an accelerator pump, you have to set the idle mixture a bit on the rich side, which will make the idle a tad "lumpy", but at least it'll take off without bogging down.

What I do is get 'er warmed up and idling in gear in the water, then tweak on one carb's mixture needle. Turn it to the lean side (CW) until the motor starts to die out, then turn the needle out until it's getting too rich. Once you know the center of that range (too-lean to too-rich), leave the needle on the rich side of center. Repeat with the other (2) carbs.

When you're all done with that, try accelerating and if you get a bog, take each needle out 1/8 of a turn (rich). Try again, if it helps, you're good, if it still bogs, try another 1/8 turn on each needle.

That should get you pretty close. If you get a nice, stable idle, you can think about adjusting the idle speed stop to get it down to maybe 800 or whatever it likes.

Hopefully that'll do the trick. Some motors are worn internally and you can't get them to idle well. I've never found the old 90-c.i. Sixes to be that fussy, my old 85hp with 100hp carbs would just purr and then scream out of the hole when you hit the throttle.

You may need to check the timing at idle with a light; if you don't have enough spark advance (maybe one tooth retarded on the belt), it won't be happy. Of course you still need to be able to get max spark advance in spec, but if you can jack-in a bit more initial timing and still set max advance, it might run better.

Conversely, if you advance the belt one tooth and then the max spark is out-of-range of adjustment, then there's not a lot you can do to mess with that.

One adjustment that's very important to idle quality, is to make sure the throttle butterflies are all completely closed at the lowest idle setting. If any of the butterflies are cracked open the least amount, that carb won't pull as much vacuum and idle quality will suffer.

The carb linkage should be adjustable if there's an imbalance between the carbs. And you can tweak the secondary pickup to make sure it's not keeping the carbs open at idle.

Since you have somewhat of a Frankenmerc ignition system, you may have to do a bit of experimenting to get 'er fine-tuned.

G'luck with that, let us know how it goes...........ed

Good Afternoon,

I am still tweaking the carbs, but getting closer every time I take it out. Still wants to die on occasion.
Here is a link to the video of the outboard in action:


or copy and paste:

https://www.youtube.com/watch?v=tY-8tY0bsIY&feature=youtu.be



At about 45 sec. I idle it down and then throttle it back up.
At about 2 min I switch to the gauges (the speedo is off--reads faster then really going)

Let me know what you think or if you can not view it.

Thank you
Matt

It sounds pretty healthy for a 95hp. If your tach is accurate, you might try a prop with 1" or 2" less pitch to see if you can get the rpm up a bit. It would be happier if your WOT rpm was closer to 5300-5500.

Far as dying in gear, it looks like it's fairly stable already at a low idle. You might need to bump up idle speed 100 rpm or so. If the idle mixture screws are a bit too lean, it'll want to stall when shifted into gear.

What plugs are you running? With a CDI ignition, you should be able to take advantage of the Permagap plugs. Champion L76V or NGK BUHW are commonly used.

Failing that, a standard-electrode plug in a Champ L82C or NGK B7HS flavor, gapped at .045", should give you plenty of spark energy.

If it's dying any other time at-speed, more likely you have an electrical issue. Note the red terminal and white terminal (on Stbd side of switchbox) must have 12V applied to keep the engine running. The white wire is +12V switched, from the ign. If you lose power to those terminals at speed, she'll die just like that.

Electrical problems usually have an on-off effect like a switch; fuel starvation issues will typically cause a slow-fade.

Pick me up lets go fishing!! Sound great,good luck with her.

Ed-Mc, I want to thank you for all your help, I think it is finally coming around. I am using NGK- BUHW spark plugs and when I trim up a little I can get the RPMs around 5300-5400.
I live here in central Texas and we have been getting stormy weather for the last week and looks like we have at least another week to go of it. As soon as I can get it back in the water I will let you know how everything turns out.

Matt