Tecumseh HH60 Ignition Cam misalignment

[zutanz]

My TroyBilt tiller over-revved, broke conn.rod, on 6hp engine, which I replaced. Reinstalled cam with mark aligned with beveled tooth - the only mark on the crank shaft gear., with piston at TDC. Then tried to set points,
I turned the crank until the intake valve opened and closed and stopped turning with piston at .080“ BTDC - the point at which ignition should occur. But, at this point, the points cam lobe - which is machined into the crankshaft - is ~40• past the opener on the points, and I can’t turn the mounting plate far enough clockwise to get to the lobe.
I would expect the points to be just opening, but the lobe is way past that point.
Does anyone have a clue as to what I might’ve done wrong with my reassembly?
Thank you for your consideration!

 

[zutanz]

My TroyBilt tiller over-revved, broke conn.rod, on 6hp engine, which I replaced. Reinstalled cam with mark aligned with beveled tooth - the only mark on the crank shaft gear., with piston at TDC. Then tried to set points,
I turned the crank until the intake valve opened and closed and stopped turning with piston at .080“ BTDC - the point at which ignition should occur. But, at this point, the points cam lobe - which is machined into the crankshaft - is ~40• past the opener on the points, and I can’t turn the mounting plate far enough clockwise to get to the lobe.
I would expect the points to be just opening, but the lobe is way past that point.
Does anyone have a clue as to what I might’ve done wrong with my reassembly?
Thank you for your consideration!

I forgot to mention that the points are gapped at .020“ and both valve clearances are within spec, at .008“- .012“.

 

[Dieseltech]

If the points cam lobe is removable, is it upside down?

 

[matthies]

I was thinking that you needed the head off and have the piston set a measured depth(using a depth micrometer) to set the points. But it has been awhile.

 

[zutanz]

If the points cam lobe is removable, is it upside down?

I wish it were, but it’s part of the crankshaft., which turns clockwise. I aligned the marks on the inside, crank and camshaft. In the picture, the piston is at .080“ BTDC on the compression stroke, right where it should be, I think, but maybe I don’t understand single piston four stroke functioning properly. Thanks!

 

[zutanz]

I was thinking that you needed the head off and have the piston set a measured depth(using a depth micrometer) to set the points. But it has been awhile.

No, that’s true, and that’s what I did. In the picture, the piston’s at .080“ BTDC on the compression stroke, right where - I believe - the points should be opening and the plug should be firing. The points mounting plate only allows slight movement, but you can see in the foto, the camlobe has already rotated past the points. What did I do wrong? And it’s already mid-May and the crops are not in the ground yet. Oh well!
Thank you for your consideration!

 

[Loosehandle]

My TroyBilt tiller over-revved, broke conn.rod, on 6hp engine, which I replaced. Reinstalled cam with mark aligned with beveled tooth - the only mark on the crank shaft gear., with piston at TDC. Then tried to set points,
I turned the crank until the intake valve opened and closed and stopped turning with piston at .080“ BTDC - the point at which ignition should occur. But, at this point, the points cam lobe - which is machined into the crankshaft - is ~40• past the opener on the points, and I can’t turn the mounting plate far enough clockwise to get to the lobe.
I would expect the points to be just opening, but the lobe is way past that point.
Does anyone have a clue as to what I might’ve done wrong with my reassembly?
Thank you for your consideration!

You really did good to get this long out of first Tecumseh

 

[Bill_Deering]

The cam lobe comes off from the crankshaft. It is on upside down. When off, inspect the keyway in the crank, and also the tang on the cam lobe.

 

[Bill_Deering]

FYI, here's a pic

 

[zutanz]

You really did good to get this long out of first Tecumseh

Thank you! Someone else has suggested that the cam-lobe is removable. I’ll look again. Thanks!

The cam lobe comes off from the crankshaft. It is on upside down. When off, inspect the keyway in the crank, and also the tang on the cam lobe.

i will look again. It looks like the love is part of the shaft. I haven’t removed the magneto and condenser. I’ll try it today. Thank You very much! I’ll let you know how it goes.

 

[zutanz]

The cam lobe comes off from the crankshaft. It is on upside down. When off, inspect the keyway in the crank, and also the tang on the cam lobe.

Yes, that was it! Thank you! I had read that it was machined into the crankshaft. I think it must have moved when I replaced the rod. I will soon m, hopefully, get my garden tilled.
I was hoping to use a friend’s horse, but he managed to break a head bolt on the 8 HP B&S engine, and then snap his drill off, in the bolt, while preparing for an easy-out. I’ll be trying to extract that tonight. It’s a .25“ bolt, so there’s not much room next to the drill but I’ll use a drill press and a small bit. I suspect I’ll need to helicoil it afterwards. The machine shop didn’t even want to try. Wish me luck! I’ll make a donation in your name to keep the site going. - Michael Neukirchen, Lane County, Oregon

 

[Bill_Deering]

Thanks very much for letting us know you found the problem. It's nice getting that feedback.
One other trick for setting the timing is using a battery powered test light or buzzer with the coil disconnected from the points. I tried to use a DVM, but it was actually too slow to respond, so the timing was late. Took a few tries to get it right.

 

[zutanz]

Thanks very much for letting us know you found the problem. It's nice getting that feedback.
One other trick for setting the timing is using a battery powered test light or buzzer with the coil disconnected from the points. I tried to use a DVM, but it was actually too slow to respond, so the timing was late. Took a few tries to get it right.

I use a digital ohmmeter. I’m set when the resistance goes to infinity. I do havea timing light, but it requires a battery hook-up in the circuit (+ lead) so I just use the ohmmeter. Do you know if there’s a noticeable difference?

 

[Bill_Deering]

Yeah, that's how I first did it. It seemed to me the engine lacked power. But I'm not talking about a timing light that you'd use when the engine is running. I wish that was possible. But just a simple light bulb and battery. The bulb goes out when the points open. I have a 12v test light I got from harbor freight. Maybe my meter was just slow to respond, we're only talking about a few degrees in timing.

 

[zutanz]

Yeah, that's how I first did it. It seemed to me the engine lacked power. But I'm not talking about a timing light that you'd use when the engine is running. I wish that was possible. But just a simple light bulb and battery. The bulb goes out when the points open. I have a 12v test light I got from harbor freight. Maybe my meter was just slow to respond, we're only talking about a few degrees in timing.

I’ll try it Bill, thanks for the suggestion. There’s a great YouTube on using a light to time this HH60 engine; very concise. It’s been a long time since I’ve used a timing light, but that’s the way I first set points on my ‘71 Honda and ‘66 VW after I rebuilt them, 50 + years ago.
Now I’m out to get this rototiller motor going and do me sum tillin‘. - Cheers!

 

[zutanz]

I’ll try it Bill, thanks for the suggestion. There’s a great YouTube on using a light to time this HH60 engine; very concise. It’s been a long time since I’ve used a timing light, but that’s the way I first set points on my ‘71 Honda and ‘66 VW after I rebuilt them, 50 + years ago.
Now I’m out to get this rototiller motor going and do me sum tillin‘. - Cheers!

I have the engine running well now and am going to reinstall it and get some tilling fine, finally.
I do need to devise a kill switch for this engine, as I had to run it out of fuel to stop it. I don’t know what happened to the original. I had borrowed it from an elderly widow neighbor - 3 or 4 years ago - since moved away - who’s deceased husband hadn’t run it in years. I will attach a small wire from the ignition to the small brass tab that the throttle lever touches, so it looks as though I’ll have the flywheel off yet again.
It needs a muffler too; I’ll see if our host has one to sell. - Michael

 

[zutanz]

I have the engine running well now and am going to reinstall it and get some tilling fine, finally.
I do need to devise a kill switch for this engine, as I had to run it out of fuel to stop it. I don’t know what happened to the original. I had borrowed it from an elderly widow neighbor - 3 or 4 years ago - since moved away - who’s deceased husband hadn’t run it in years. I will attach a small wire from the ignition to the small brass tab that the throttle lever touches, so it looks as though I’ll have the flywheel off yet again.
It needs a muffler too; I’ll see if our host has one to sell. - Michael

New problem : shut-off. I had trouble shutting engine off. I see a brass spade connection tab where the throttle wire bottoms out, near the carb, but there’s no wire going to the coil. As I mentioned, I got this second hand and it’s a continuous journey of discovery. I can make a new wire for it, I just need to know where to attach it on the coil. I just set the points but didn’t see an extra wire from the condenser, just the one going to the points; I think there must have been one originally. Do you know where I should attach one? I’ll take off the flywheel again and look around, tomorrow. Thanks for your help! - Michael

 

[Mark-Ia]

A screwdriver and short the spark plug and it will die.

 

[zutanz]

A screwdriver and short the spark plug and it will die.

I took flywheel off, found a brass electrical spade fitting , where the condenser wire attached to the points. So, I ran a wire from this to a small toggle that I attached to the control plate, near the carb. Problem solved, though I’ll keep my eyes open, just to see if I can spot an original setup on another tiller. I could as well have attached a wire from the spark plug - which is what I tried first - but I wanted something more like the original.

 

[zutanz]

I took flywheel off, found a brass electrical spade fitting , where the condenser wire attached to the points. So, I ran a wire from this to a small toggle that I attached to the control plate, near the carb. Problem solved, though I’ll keep my eyes open, just to see if I can spot an original setup on another tiller. I could as well have attached a wire from the spark plug - which is what I tried first - but I wanted something more like the original.

This didn’t do anything, so I tried a toggle switch attached to the spark plug. I don’t think the switch could handle the load, since it worked fine attached to an ohmmeter, so I’m going to get a beefier toggle switch that can handle higher voltage. In the meantime, I’ll use a wire attached to the end of the spark plug and ground it when I need to turn the engine off, if I don’t get zapped too badly.