How do I set the points gap correctly without a timing light?

[three4rd]

I have new points in place (for my 129) and gapped to .020, but all I did was turn the engine by hand until the little bar at the points is pushed out all the way. Then, I locked it in place. However, I find that I can continue to turn the engine further and really not much happens. Continued turning, of course, retracts the bar again. So am I correct that as long as I turn the engine and stop at the first point where the bar is out all the way - is that the correct spot? What about this "sight hole" that I read about in the service manual? I don't have a timing light, and so am trying to be as accurate as I can without one. The above procedure I described is what I did the last time I changed the points 6 years ago and everything was fine, so hopefully I did it right again this time. Thanks...

[olds45512]

http://www.onlycubcadets.net/forum/s...ad.php?t=33461

[three4rd]

Great...thanks! I have to go back in my notes from when I took off the front bearing to find out what the correct rotation direction is. I'm thinking it's counter clockwise, but not certain. I know that when I set the points this afternoon I was turning clockwise. Does it really matter which way you turn as long as you know the points are open at the correct place, i.e. at the top of the compression stroke?

[olds45512]

The engine spins counter clockwise from the pto side and clockwise from the drive shaft side.

[three4rd]

Right...counter-clockwise. I checked the sight-hole...can't find any marks due to dirt and rust. What's interesting, though, is that there is a large white mark (paint?) on the flywheel at one point, and then another (smaller) white mark about an 8th of a turn later. Could this mark have been put there for someone's previous timing efforts? So, anyway, not sure how to proceed next. I'm disappointed the T and S marks aren't there anymore. I considered doing some scraping on the flywheel to see if the letters would be revealed, but I can't imagine that depositing scraped dirt and rust into the engine would be a great idea.

Another thing that has me confused is the recommended carb float setting on page 35 of the manual - in normal operating position, it says to have the float drop limited to 1 1/32" between the machined surface of the body and the bottom of the free end of the float. This setting will not allow the needle to open very far. The same measurement on mine is around 9/32". It hangs down at a much greater angle than suggested in the manual. And, what makes even less sense is that the float level, when inverted, calls for 11/64" clearance between body and the free end of the float. I have very close to this. It looks just about parallel as shown in the manual. So, what doesn't seem to make sense is - how can the float level be nearly correct and yet the float drop measurement be so far off? Won't bending whatever needs to be bent to bring up the float drop angle also screw up the float level? To the best of my recollection, I've not changed this float setting ever and the tractor has been running very well for the past 36 years that I've had it. Should I just leave it as is?

[john hall]

Originally Posted by three4rd

Right...counter-clockwise. I checked the sight-hole...can't find any marks due to dirt and rust. What's interesting, though, is that there is a large white mark (paint?) on the flywheel at one point, and then another (smaller) white mark about an 8th of a turn later. Could this mark have been put there for someone's previous timing efforts? So, anyway, not sure how to proceed next. I'm disappointed the T and S marks aren't there anymore. I considered doing some scraping on the flywheel to see if the letters would be revealed, but I can't imagine that depositing scraped dirt and rust into the engine would be a great idea.

The little bit of debris you scrape off the flywheel won't hurt anything. Trust me, there is 1,000 x's more than that inside the air shroud. The marks should be stamped into the flywheel. I don't think they line up exactly in the window, I think they may be more toward the engine block side. You'll know you are in the neighborhood when the points open--could be a little before, maybe a little after, but at least you can narrow down the search area. I had a small wire brush in a drill that would fit through the hole so I could wire brush the flywheel, really helped a lot.

[J-Mech]

Originally Posted by three4rd

What's interesting, though, is that there is a large white mark (paint?) on the flywheel at one point, and then another (smaller) white mark about an 8th of a turn later. Could this mark have been put there for someone's previous timing efforts?

Use the two painted marks. Scrape off the paint. You will likely find the stamped marks have been painted white. Easy peezy. Someone already did the work for you. Suggestion: Once cleaned, paint them again. Makes them easier to find later.

Originally Posted by three4rd

Another thing that has me confused is the recommended carb float setting on page 35 of the manual - in normal operating position, it says to have the float drop limited to 1 1/32" between the machined surface of the body and the bottom of the free end of the float. This setting will not allow the needle to open very far. The same measurement on mine is around 9/32". It hangs down at a much greater angle than suggested in the manual. And, what makes even less sense is that the float level, when inverted, calls for 11/64" clearance between body and the free end of the float. I have very close to this. It looks just about parallel as shown in the manual. So, what doesn't seem to make sense is - how can the float level be nearly correct and yet the float drop measurement be so far off? Won't bending whatever needs to be bent to bring up the float drop angle also screw up the float level? To the best of my recollection, I've not changed this float setting ever and the tractor has been running very well for the past 36 years that I've had it. Should I just leave it as is?

Let me save you a ton of headache and time. Turn the carb upside down. Make the float parallel. Next step, reassemble. Don't worry about the drop measurement. Who cares, when the bowl is full, the only measurement that matters is the closed one.

[three4rd]

Originally Posted by J-Mech

Use the two painted marks. Scrape off the paint. You will likely find the stamped marks have been painted white. Easy peezy. Someone already did the work for you. Suggestion: Once cleaned, paint them again. Makes them easier to find later.




Let me save you a ton of headache and time. Turn the carb upside down. Make the float parallel. Next step, reassemble. Don't worry about the drop measurement. Who cares, when the bowl is full, the only measurement that matters is the closed one.

I would have thought the painted/stamped marks would be farther apart though. They're pretty close together. Is it likely that I wouldn't even really need to calibrate it with the flywheel at all? I mean, if the points are open when the bar is out all the way, isn't that pretty close to when it needs to fire during compression? Maybe I just got lucky 6 years ago...Anyway, I'm getting pretty good at taking off and putting back on that lower screw on the points cover! This will be the third time since I started working on all this. I had to buy feeler gauges (had a .020 but who knows where it got to since I used it 6 years ago). I noticed that, when I took them out of the pack, they were all oily - so I didn't think about it and wound up putting the gauge in between the points with (probably anyway) the oil on the gauge. When I talked to my brother about it, he suggested that leaving the oil on the points would probably not be the best thing - so opened them up again and cleaned them off - not sure if there actually was oil on them or not but didn't want to take the chance. Now, if I have to recheck timing, the cover can come off again. I'm soon ready for the points cover remove and reinstall competition

Sounds good about the carb setting! Works for me. Easier=better!

[J-Mech]

Proper timing is important. Just gapping the points isn't accurate. I'm not going to try and convince you why you need to do it right. I'm a mechanic, you're not. I can't make you do it. But, if you don't follow advice after seeking it, I can promise you, I (at least) will find other threads to follow.

No.... you don't need to use the flywheel to time an engine. The marks are just decorative.

[ol'George]

You have been given good advice here by all.
As I told you in the PM, when the points just open, the coil fires.
Also @ that instant, the mark on the flywheel, needs to be visible in the hole.
if it is not, adjust the points more open or less open, so the mark is visible.
Most of us don't use a feeler gauge, although it works, and is close.
Once you set timing, lining the marks up, it will be good for another 36 years.
Now get a little penlight to see in the hole and scrape the side of the flywheeeeeel with a bore brush or small screwdriver or whatever you have, and I'll bet you will find the line stamped on the flywheel ( prolly in the middle of the white marks someone kindly put on it for you previously).
Don't give up, have patience, when it is right, you will hear a difference, and it will start/run better,-- might even put off the overhaul till you save up a few $$ to have Jon or another top notch mechanic, rebuild it for you.