Just got Old Short Stack back together after replacing timing gears and governor. Amazingly, it starts, but only runs half a second or so and quits. (Sounds good for those few turns.) So it"s getting a spark, and gas into the carb., but seems to only burn what"s in the carb (after choking and getting fuel into it). But it seems it should run a little longer on the gas in the carb. I"m guessing cleaning the carb. is the next likely thing to do. But is there any thing else it could be? She"s only been out of commission for about a month or so.
- Thread starter Bill Carr
- Start date
ScottyHOMeY
Well-known Member
The carb may need work, but with what you've been doin (especially if she was runnin' alright before you had the timing gear problem) I'd go back over my recent work if it was mine.
Did you wind up replacing the gear on the crank as well as the cam gear? Did both your replacements have the punch marks that were missing from your governor gear?
First thing I'd do is get her to crank and fire and die once more, then check whether your plugs are wet with gas. If not, then the crb might be suspect. If they are wet, I would sooner suspect something in the timing (either cam or spark) before the carb.
I don't mean to insult you, but ugly as it sounds, I'm gonna ask. Are you certain you had the motor at TDC on the *compression* stroke of #1 when you lined up the single punch marks between the cam and crank gears? If you matched up the punch marks with #1 at the top of the exhaust stroke (meaning #4 was at the top on compression),your cam and therefore the valves would be out of time. You can check that out by watching the valves as you bring #1 around to TDC on compression. As #1 comes up, the stems on both your front valves should be all the way up and not moving. At the same time, the exhaust valve on #4 (the eighth, very hindmost valve) should be open (down) and close when the motor comes up to TDC. If that's the case, and you had the punch marks lined up, your cam and valve timing should be okay.
If that's okay, then ask the same question relative to when you put the governor gear back in. If you were on exhaust instead of compression when you timed the mag, you'll be 180* out, with your spark on #4 when it should be on #1. That's easy enough to check. Bring the motor up to TDC #1 compression, and see where your distributor rotor is pointing. If it's on #1, that should be okay, too.
If those are both good, then it's time to look at the carb.
That's how I'd go at it.
Did you wind up replacing the gear on the crank as well as the cam gear? Did both your replacements have the punch marks that were missing from your governor gear?
First thing I'd do is get her to crank and fire and die once more, then check whether your plugs are wet with gas. If not, then the crb might be suspect. If they are wet, I would sooner suspect something in the timing (either cam or spark) before the carb.
I don't mean to insult you, but ugly as it sounds, I'm gonna ask. Are you certain you had the motor at TDC on the *compression* stroke of #1 when you lined up the single punch marks between the cam and crank gears? If you matched up the punch marks with #1 at the top of the exhaust stroke (meaning #4 was at the top on compression),your cam and therefore the valves would be out of time. You can check that out by watching the valves as you bring #1 around to TDC on compression. As #1 comes up, the stems on both your front valves should be all the way up and not moving. At the same time, the exhaust valve on #4 (the eighth, very hindmost valve) should be open (down) and close when the motor comes up to TDC. If that's the case, and you had the punch marks lined up, your cam and valve timing should be okay.
If that's okay, then ask the same question relative to when you put the governor gear back in. If you were on exhaust instead of compression when you timed the mag, you'll be 180* out, with your spark on #4 when it should be on #1. That's easy enough to check. Bring the motor up to TDC #1 compression, and see where your distributor rotor is pointing. If it's on #1, that should be okay, too.
If those are both good, then it's time to look at the carb.
That's how I'd go at it.
Janicholson
Well-known Member
I'll add to Scotty's good ideas that fuel must be available in a solid stream to the carb. Thus if the line, and screen at the carb fitting are passing fuel in a 1/8" or bigger stream, it should be OK.
Pulling off the float bowl is pretty easy checking fuel delivery to the needle and seat (again a heavy flow) is next. JimN
Pulling off the float bowl is pretty easy checking fuel delivery to the needle and seat (again a heavy flow) is next. JimN
teddy52food
Well-known Member
If he was 180 off , it would never start and run. Try choking it as it dies. If it picks up again, the carb is plugged in the jets. Make sure you have the wire from the switch to the coil is tight. (battery ign)
Bringselpup
Member
Had this very thing today. In order to drive her back to the front of the shop I had to pull the choke out all the way. I checked my fuel delivery from the carb back to the bowl and saw where the bowl wasn't filling smoothly at all. Unscrewed it from the bottom of the tank and the entire inlet to my fuel bowl was filled with crap. I'm back doing chores now that I cleared it.
Scotty, don"t worry about insulting my mechanical genius. I haven"t got any. I appreciate the assistance (I thank everybody who has posted on this). Yes, I replaced the drive as well as the camshaft timing gear and governor.
The timing marks were evident on all but the new governor. I used the old governor to mark where the mag. drive slot was when when in register, and got the new one just about exactly where the old one was aligned.
The first time I tried to start it, I got nothing, and then took the magneto off and turned it 180, after which I was able to get initial start-up.
I use only a hand crank -- the generator has been gone for over 20 years. She doesn"t start with the choke on. I turn the crank until gas drips out from the bottom of the carb., then turn the choke off. Then, after one or two cranks, she"ll fire up for a several revolutions. Working the choke doesn"t help. There"s really not enough time to experiment around when it kick off, but the governor (which I originally suspected of maybe shutting it down), doesn"t effect it. I disconnected the link and it still shut down after firing up. I have to repeat the process of choking gas into the carb. to get it to fire up again.
I admit that I didn"t know whether the TDC was either the compression or exhaust stroke when I meshed the drive and cam gears. It seems that they could only be meshed at the timing marks in one possible position, so I figured I couldn"t go wrong.
Would it be possible to have the timing wrong if I"m sure the timing marks of drive and cam gears were in proper register? Could it start at all for half a second or so, sounding like a good firing succession for several revolutions if it was somehow 180 out in timing?
The timing marks were evident on all but the new governor. I used the old governor to mark where the mag. drive slot was when when in register, and got the new one just about exactly where the old one was aligned.
The first time I tried to start it, I got nothing, and then took the magneto off and turned it 180, after which I was able to get initial start-up.
I use only a hand crank -- the generator has been gone for over 20 years. She doesn"t start with the choke on. I turn the crank until gas drips out from the bottom of the carb., then turn the choke off. Then, after one or two cranks, she"ll fire up for a several revolutions. Working the choke doesn"t help. There"s really not enough time to experiment around when it kick off, but the governor (which I originally suspected of maybe shutting it down), doesn"t effect it. I disconnected the link and it still shut down after firing up. I have to repeat the process of choking gas into the carb. to get it to fire up again.
I admit that I didn"t know whether the TDC was either the compression or exhaust stroke when I meshed the drive and cam gears. It seems that they could only be meshed at the timing marks in one possible position, so I figured I couldn"t go wrong.
Would it be possible to have the timing wrong if I"m sure the timing marks of drive and cam gears were in proper register? Could it start at all for half a second or so, sounding like a good firing succession for several revolutions if it was somehow 180 out in timing?
teddy52food
Well-known Member
Is there a magneto shop near you? Maybe the spark is weak after the impulse kicks off. Have them run it and check it at slow speed just after the impulse lets go. If you can get gas to drip by choking,try to leave the choke about 3/4 on instead of opening it all the way. If it stays running it should start to chug and show black smoke. If it does, open the choke just a small amount to let in more air. Is there a main jet adjustment on the carb?
ScottyHOMeY
Well-known Member
Hi, Bill.
#1 and #4 travel up and down in the block as a pair. #2 and #3 do the same, just exactly 180* opposite of 1 and 4.
While #1 is coming up and compressing (both valves closed), #4 is exhausting (coming up with exhaust valve open, intake closed). At the same time, #3 is on its way down on it's intake stroke (intake valve open, exhaust valve closed) and #2 is on its way down actually firing after the spark (again, both valves closed).
The first gear, the drive gear on the crankshaft, has 33 teeth to it. It's half the diameter of the cam gear which has 66 teeth. Result is that the crank comes around twice for every time the cam turns. That may sound odd or mysterious, but makes sense if you remember that at TDC you will alway have two pistons up and two pistons down at their extremes, but doing different things at that very moment as described. The trick, problem . . . is, or may be, that if you had #1 at TDC on the wrong stroke when you matched up the marks between the crank and cam gears, everything on the front of the motor will look right, but you'll have the wrong valves doing the right thing at the wrong time, if that makes sense.
The good part is that if you lined up the single punch marks between the crank and cam gears correctly, the worst scenario is that you will have the cam 180* out of where it originally was, and you can fix it with the ignition timing without tearing the front back off the motor. TDC on #1 is also TDC on #4. You just need to match the spark up to the point that it will do you some good.
That will mean turning your distributor/mag/governor gear until the rotor is at #1 at the top of the #1 compression stroke.
It's good that you're using a hand crank. Much easier to check things out with than a starter motor.
It can be a bear to find, but find the TDC mark on your flywheel (Use brake cleaner and scrapers, whatever you have to to find it). That's the only place on the motor that TDC is marked. Problem is it's not marked particularly well. You can see the mark looking up through the oval shaped hole on the bottom of the torque tube, but the stamping on the flywheel is so shallow that it's often obscured and may take some scraping to find. You can get near to TDC by looking in the plug hole or putting a stiff wire or screwdriver on top of the piston through the plug hole and watching its motion, but the mark is much more reliable. (On the other point, of engine orientation, the mark on the flywheel, when you find it, will be marked TC 1-4, referring to both of those cylinders being at TDC.)
To get to TDC and know which stroke you're on on #1 . . . pull all your plugs out so the engine will turn easily. While someone turns the crank for you, stuff whichever finger fits into the plug hole on #1. On the firing stroke, the piston will be moving down with the valves closed and you should feel a strong vacuum. On exhaust that follows you shouldn't sense much pressure either way. On intake, the next stroke, again not much pressure, though you might feel a little pop in between the two strokes. On compression, you will feel enough pressure to blow your fingertip out of the hole. The end of that stroke is where you want to set things up.
Note the angle of your hand crank when you hit TDC on compression (accuracy is not critical at this point), then go back to what I described in my last post. With the valve cover off, have your helper turn the crank one-and-a-half turns (accuracy is not too critical here -- if you're that far out it will be evident) while you watch the front two valves and the back two. From that point to continuing on to two full turns, you should see both front valves closed (at top) and not moving. Of the back two, the one at the rear, the exhaust valve for #4, should be down (open) at 1-1/2 turns and rise to the top (closed) just as you get to two full turns. At that point, your cam is timed up fine.
Get your motor to that point, line up the mark on your flywheel to be exactly at TDC (If your helper should crank to where it goes past the mark on the flywheel, you can either back up using the fan to turn the other direction, or go TWO turns around and come up on it more slowly to get it on the mark.) and then set your mag up to fire on #1. If everything else is in order, that's the spot where she'll run.
There are those that would argue for just swapping wires to get your firing order in the mag back in order, but the gear ratios defy 4:1 (66 doesn't divide evenly by four), and will leave your starting spark as much as 5* out of time, which could be overcome by the crankig spees of a starter motor, but can make the differnce between starting and not with a crank..
Apologies for length.
Let us know how you make out.
#1 and #4 travel up and down in the block as a pair. #2 and #3 do the same, just exactly 180* opposite of 1 and 4.
While #1 is coming up and compressing (both valves closed), #4 is exhausting (coming up with exhaust valve open, intake closed). At the same time, #3 is on its way down on it's intake stroke (intake valve open, exhaust valve closed) and #2 is on its way down actually firing after the spark (again, both valves closed).
The first gear, the drive gear on the crankshaft, has 33 teeth to it. It's half the diameter of the cam gear which has 66 teeth. Result is that the crank comes around twice for every time the cam turns. That may sound odd or mysterious, but makes sense if you remember that at TDC you will alway have two pistons up and two pistons down at their extremes, but doing different things at that very moment as described. The trick, problem . . . is, or may be, that if you had #1 at TDC on the wrong stroke when you matched up the marks between the crank and cam gears, everything on the front of the motor will look right, but you'll have the wrong valves doing the right thing at the wrong time, if that makes sense.
The good part is that if you lined up the single punch marks between the crank and cam gears correctly, the worst scenario is that you will have the cam 180* out of where it originally was, and you can fix it with the ignition timing without tearing the front back off the motor. TDC on #1 is also TDC on #4. You just need to match the spark up to the point that it will do you some good.
That will mean turning your distributor/mag/governor gear until the rotor is at #1 at the top of the #1 compression stroke.
It's good that you're using a hand crank. Much easier to check things out with than a starter motor.
It can be a bear to find, but find the TDC mark on your flywheel (Use brake cleaner and scrapers, whatever you have to to find it). That's the only place on the motor that TDC is marked. Problem is it's not marked particularly well. You can see the mark looking up through the oval shaped hole on the bottom of the torque tube, but the stamping on the flywheel is so shallow that it's often obscured and may take some scraping to find. You can get near to TDC by looking in the plug hole or putting a stiff wire or screwdriver on top of the piston through the plug hole and watching its motion, but the mark is much more reliable. (On the other point, of engine orientation, the mark on the flywheel, when you find it, will be marked TC 1-4, referring to both of those cylinders being at TDC.)
To get to TDC and know which stroke you're on on #1 . . . pull all your plugs out so the engine will turn easily. While someone turns the crank for you, stuff whichever finger fits into the plug hole on #1. On the firing stroke, the piston will be moving down with the valves closed and you should feel a strong vacuum. On exhaust that follows you shouldn't sense much pressure either way. On intake, the next stroke, again not much pressure, though you might feel a little pop in between the two strokes. On compression, you will feel enough pressure to blow your fingertip out of the hole. The end of that stroke is where you want to set things up.
Note the angle of your hand crank when you hit TDC on compression (accuracy is not critical at this point), then go back to what I described in my last post. With the valve cover off, have your helper turn the crank one-and-a-half turns (accuracy is not too critical here -- if you're that far out it will be evident) while you watch the front two valves and the back two. From that point to continuing on to two full turns, you should see both front valves closed (at top) and not moving. Of the back two, the one at the rear, the exhaust valve for #4, should be down (open) at 1-1/2 turns and rise to the top (closed) just as you get to two full turns. At that point, your cam is timed up fine.
Get your motor to that point, line up the mark on your flywheel to be exactly at TDC (If your helper should crank to where it goes past the mark on the flywheel, you can either back up using the fan to turn the other direction, or go TWO turns around and come up on it more slowly to get it on the mark.) and then set your mag up to fire on #1. If everything else is in order, that's the spot where she'll run.
There are those that would argue for just swapping wires to get your firing order in the mag back in order, but the gear ratios defy 4:1 (66 doesn't divide evenly by four), and will leave your starting spark as much as 5* out of time, which could be overcome by the crankig spees of a starter motor, but can make the differnce between starting and not with a crank..
Apologies for length.
Let us know how you make out.
Jim Becker
Well-known Member
It wouldn't run at all if you didn't have the timing close to correct. I think your problem is fuel related -- fuel flow restriction or vacuum leak.
Similar threads
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.
Copyright © 1997-2024 Yesterday's Tractor Co.
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy