Mcculloch 1 40 timing issue

[Tylersummertime]

Hi I have a McCulloch 1 -40 chainsaw and I'm having a problem with the timing there's no hole in the flywheel for a fixed ignition system and I don't know where to set the points at I know it's 18 thousands of an inch but I don't know if it's top dead center or what because I'm getting spark I then when I sometimes regap the breaker points I don't get Spark and it was running when it was dropped off plenty of compression and I don't know what to do can you please help me

 

[davidtown]

In times like this I have rotated the crankshaft until the points fully open. Somewhere between starting to reach full open and starting to close is the spot that I cram the feeler gauge in.

 

[Tylersummertime]

I did this even made marks on the points case. Can you put a electronic ignition module chip on this saw.

 

[davidtown]

I can't say for certain that you can install a chip. Some guys say their older Macs don't perform as well with the chips.

An intermittent spark could be a different issue than points gap. Make sure you have a good plug, good wire to the plug, good condensor and a good coil. All these components can be tested individually. You can find out how to test them by doing a search. One last thing is to disconnect the kill switch from the coil for the off chance it is causing the problem.

 

[SS Sniper]

Just rotate the motor until the cam on the crank is on it’s base circle; you’ll know this when the points don’t get any farther away from each other. Make sure they’re clean and not worn too much. Set them to the specified gap and see what you got. Maybe play around with it a little and set them a thousandth closer or wider and see if that helps. Be careful with that though.

If it doesn’t run right with the recommended gap, or very close to it, then I’d bet you have other problems. As David said, the kill switch is a great place to start, as well as cleaning connections and grounds.

The system on these is very simple and IMO not worth putting a chip in. Many Mccullochs used the same ignition system.

 

[Timdog]

Make sure to clean the Magneto and make sure the coil is gapped right

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[2broke2ride]

I'm running an atom module in my 1-52. It runs great and starts great.

 

[Tylersummertime]

Well I installed the electronic ignition module that I used for some of my saws and it's puffing out a white cloud of smoke and it doesn't start so I think I'm going to put the points back on thank you

 

[Tylersummertime]

It's the weirdest thing though I was getting spark before before I tore down and now I'm not getting any Spark

 

[2broke2ride]

It sounds to me like you have it flooded at this point. Hold the throttle wide open, turn the saw so the muffler faces down and pull it a few thousand times. Make sure the kill switch is on too lol.
My experience with the points in these is if you even look at them wrong they lose contact. Either replace with NOS or switch to electronic.

 

[Okie]

You need to install a NEW set of points and condenser and set the gap at spec's, then before you install the flywheel drag a clean non fuzzy paper through the points while they are closed or a dollar bill. I confirm that points are making good contact with a ohmmeter. Set the air gap on the coil using a credit card or set the gap a .010-.012. You can search on-line about how to properly set the points and magneto coil air gap. It's a no brainer for a chainsaw.

I've tried some of the NOVA type electronic chips in Mac's and did not get any good results. Only reason I tried them is the chip was easy to install without removing the flywheel for testings and I had to do some serious browser shopping to find New Old Stock points and condensers. ( eventually found them on flea bay very reasonable. by doing a saved search. Some of the chips even required reverse polarity timing to get a run.

Some like the electronic chips and when I contacted the seller of the NOva chips they indicated they were going to quit selling them due to complaints and refunded by purchase price and told me to throw them in the trash.

From several years of playing with points ignitions I've learned that:
Re-gapping and or filing old points is in the same category as peeing into a strong wind.

 

[Tylersummertime]

Ok thanks for all the help. The thing is when I look up the 1:40 it says fix the ignition but there's no hole in the flywheel to put that pin through the side of the crankcase and into a flywheel so I don't know I guess I'll fiddle with it again

 

[Timdog]

Why do you need a hole in the flywheel?

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[2broke2ride]

That pin you are talking about is just to lock the flywheel so you can get the nut off. It serves no other purpose. You need to turn the crank until the points are at their widest opening, gap them to .018, clean with a dollar bill, and that is about it.

 

[Okie]

That pin you are talking about is just to lock the flywheel so you can get the nut off. It serves no other purpose. You need to turn the crank until the points are at their widest opening, gap them to .018, clean with a dollar bill, and that is about it.

Some of them old dogs have a hole in the cover and flywheel so as you can insert a pin or small phillips head screwdriver or nail to lock the flywheel so the nut can be loosened. Some do not even have the access hole for such.
Do this if you do not have a Impact wrench to remove the flywheel nut. (but do not use a impact wrench to tighten the nut when going back together.
To lock the flywheel take the muffler off and rotate the crank until the piston goes down and then insert a small cotton rope on top of the piston or take the spark plug out and do the same. In either case take out the spark plug because the rope will squish the gap together on the spark plug.

I just now noticed that you had the flywheel off before.

Constantly going back and removing and installing a flywheel due to trying to get old worn out points to operate is not a good thing especially if you are use the whacko method of flywheel removal. That is another good reason I suggested you install NEW points and condenser. I do not use the whack method (unless I'm working on Bro in Laws eq and he is not watching) I use a puller on my own eq.

Them old 1-40, 1-50 series of Mac's usually will only start cold if you tie the trigger throttle wide open with a solid copper wire and give em a prime of gas and with the chainsaw on the ground and give it sharp fast cranks with the kill switch ON. (leave the choke off if you have primed it through the carb throat or muffler. Just slide the copper wire down off the trigger when it starts and leave it dangling for next time. If it starts and runs for little while and dies prime it again and go. they are usually really cold natured and always want to start with a full throttle even when warmed up..

If it has the old cast muffler with the little holes I just prime through the muffler when the engine is cold. (if the breather cover is still on and has the carb covered)

If you have a ohmmeter or continunity light you can confirm that points are closing BEFORE you install the flywheel.
NEW points will need the paper cleaning method because a feeler gauge will add a skim of oil skum to the points and they will sometimes not make contact.

 

[Timdog]

I think he's talking about timing hole

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[Okie]

The Mac 1-40 do not have a TIMING HOLE. the hole in the case if present is only for inserting a 3/16 pin to lock the flywheel when removing or installing the flywheel nut and some flywheels did not have the hole, just had a slot in the side of the flywheel for the pin.

For timing rotate the crankshaft until the points are at their widest gap and set them a .018 and then rotate the crankshaft and re-check. Sometimes tightening the screw will slightly change the points gap. Make sure that the screws in the points box that holds the points is secure. (so that when the points cover is installed and it's screw tightened that the point gap does not change)

Now Mac had at one time a special timing tool that fit over the crank and a slot for the flywheel key to hold the little flat indicator tool to set the point gap for exact engine timing but it was rarely ever used by regular mechanics because it was not readily available. (and really not needed) Set new points at .018 with the adjustment screw secure and she will be timed correctly. Set the magneto to flywheel magnet air gap to .010.

 

[2broke2ride]

The Mac 1-40 do not have a TIMING HOLE. the hole in the case if present is only for inserting a 3/16 pin to lock the flywheel when removing or installing the flywheel nut and some flywheels did not have the hole, just had a slot in the side of the flywheel for the pin.

For timing rotate the crankshaft until the points are at their widest gap and set them a .018 and then rotate the crankshaft and re-check. Sometimes tightening the screw will slightly change the points gap. Make sure that the screws in the points box that holds the points is secure. (so that when the points cover is installed and it's screw tightened that the point gap does not change)

Now Mac had at one time a special timing tool that fit over the crank and a slot for the flywheel key to hold the little flat indicator tool to set the point gap for exact engine timing but it was rarely ever used by regular mechanics because it was not readily available. (and really not needed) Set new points at .018 with the adjustment screw secure and she will be timed correctly. Set the magneto to flywheel magnet air gap to .010.

Like I said lol......... it's really very simple. No need to overthink it.

 

[Okie]

Like I said lol......... it's really very simple. No need to overthink it.

From experience: Think outside of the box and use common sense when reading service manuals. Do not get locked in to following exactly step by step every little service manual recommendation procedures.

 

[Timdog]

The old saws are pretty easy to work on as far as taking it apart and putting it back together

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