what happens if you wire ignition chip backwards?

[CamMann]

What happens if you wire an ignition chip backwards?
I just picked up a Mac SP-81 that had no spark. Diagnosed problem to be the points & condenser. Cleaning & gapping the points didn't help. So, I put on an electronic conversion chip from another old parts-saw i had. Now I have strong spark, and excellent compression, but the saw won't sputter with fuel down the carb. There's just a small puff of smoke out the muffler & decompression valve, no sputter. I'm wondering, if I installed the chip's wiring backwards, could I be getting spark at the wrong time? Or would there be no spark at all if that were the case? Any advice would be much appreciated.

 

[nolids]

99% of the ignition modules are negative ground. You need to get a timing light since the modules change the timing.

 

[CamMann]

Interesting, thanks. I wonder if condensers are fairly saw-specific? I'm thinking it might be easier to just pull a working condenser off another saw, rather than buy a timing light & learn about timing adjustments.

 

[nolids]

Whenever you change the points/condenser out to an ignition module the timing needs to be reset.

 

[Justsaws]

Just reverse the wires to the module and retry. Many times there will simply be a weak spark if they are hooked up backwards, corrected by reversing the wires.

 

[CamMann]

QUOTE="Justsaws, post: 6917571, member: 9324"]Just reverse the wires to the module and retry. Many times there will simply be a weak spark if they are hooked up backwards, corrected by reversing the wires.[/QUOTE]

I'll give it a go, thanks. Looked like a pretty strong spark though, and I gave it a few more pulls around sundown and could see a burst of flame in the muffler with the puff of smoke. So, my gut says it's sparking up strong, but maybe just at the wrong time. Idk, never had to mess with these chips before. Will definitely reverse the wires and see what happens.

 

[CamMann]

Whenever you change the points/condenser out to an ignition module the timing needs to be reset.

Huh, I've heard that to be the case, but I've also read a number of people who simply installed them without needing to adjust timing. Hoped I'd luck out, lol.

 

[alexcagle]

I know some of the OEM ignition modules have timing curves tailored to enhance performance, but I don't know about the Nova II modules.
Double check your woodruff key for shearing?
Try pulling the plug, then sticking a pencil tip to the top of the piston; finding TDC.
Then look at how much the flywheel leads the coil.
It's easier than pulling the flywheel sometimes.
About 1"counterclockwise of center coil to center of flywheel magnets is going to be close.
I have ran into a reverse wired Nova II module too.

 

[CamMann]

Just reverse the wires to the module and retry. Many times there will simply be a weak spark if they are hooked up backwards, corrected by reversing the wires.

I think you nailed it! She popped & purred after I reversed the wires. I'd copied the wiring of the chip's donor saw, and was hesitant to deviate from that. Thanks for the encouragement. I think I might just be a carb-rebuild away from having it going.

 

[Okie]

I think you nailed it! She popped & purred after I reversed the wires. I'd copied the wiring of the chip's donor saw, and was hesitant to deviate from that. Thanks for the encouragement. I think I might just be a carb-rebuild away from having it going.

Good Luck with them Nova chips. From experience: I've tried them Nova chips on Mac saws, First one I installed worked great for one day. I thought it was great until the chip failed. Next day installed another Nova chip, exact same model chip and had to reverse the polarity to finally get a run, had weak fire with neg polarity, changed polarity and could tell the saw was firing too fast, kickback on rope pull finally got a run but was out of time with reversed polarity. finally got a run for about 30 minutes. Had 3 chips fail. I went back to points and condenser. Found NOS points and condenser on flea bay with a saved search for less than a nova chip. My old points and condenser was over 40 years old. Some guys say they can polish, burnish, file old points and make them like new. I've never seen such and I have all kinds of high dollar points burnishing tools. If you install new points, drag a clean non-fuzzy through them when they are closed (or use a dollar bill) BEFORE installing the flywheel. New points sometimes have a oil film glaze and won't make contact.

Some guys have good luck with the Novas, some are reversable polarity, some are not. My old Mac's are OEM and work great now.

 

[rogue60]

What happens if you wire an ignition chip backwards?
I just picked up a Mac SP-81 that had no spark. Diagnosed problem to be the points & condenser. Cleaning & gapping the points didn't help. So, I put on an electronic conversion chip from another old parts-saw i had. Now I have strong spark, and excellent compression, but the saw won't sputter with fuel down the carb. There's just a small puff of smoke out the muffler & decompression valve, no sputter. I'm wondering, if I installed the chip's wiring backwards, could I be getting spark at the wrong time? Or would there be no spark at all if that were the case? Any advice would be much appreciated.

 

[CamMann]

Well, it's been a week and the chip has held up fine. Granted, I've only used it for a few small, odd jobs. I'll aim to get supplies on hand to replace the points & condenser in case the chip fails. So far, so good though. After sorting out the chip, cleaning the carb, cleaning the kill switch contacts, & replacing the gasket under the carb-boot... seems like I've got a nice running machine. The saw cranks right up in two or three pulls and cuts beautifully. Thanks all, for the helpful input!

 

[nolids]

I've done extensive internet research into chainsaw ignitions while I spent weeks trying to get my SEM GE to work in my early '80's Sachs Dolmar 133. The SOB would start and run from 3 seconds to one minute, die and refuse to run again for 24 hours again for the allotted few seconds. Very frustrating when you are dealing with an old saw nobody has parts for who also tell you there are no more fixes from other saws available either.

It was the German Sagenspezi ignition plate that finally got me going, after I ignored their warning it would not work on my saw. I had to time the chainsaw from scratch, drill new holes in the ignition plate adjustment and use a timing light to make it all work.

And does it work!! You'd have to shoot me and take the chainsaw from my dying hands to get it away from me after all the months I spent on it. And yes, the Nova works-- it just doesn't like cylinder heat.

 

[Brufab]

Great info I'm getting ready to do one on a old remington