IH model lb engine

[wisch79]

Hello all,
I recently got a LB 3-5 engine from a fellow teacher. It was her dads engine and she was going to haul it to scrap if I didnt want it. I have been trying to see about getting it running, but I think it may be quite a challenge. I have never messed with a mag before, so I thought I would ask you all for some help. It is missing the cap where the plug wire goes and the rest does not look to good. I took the points cover off and the points were very corroded, but everything else looks intact. There was also a automotive type coil mounted on top, so I wonder if if they have bypassed it somehow. I have attached some pictures to give you an idea of what I am dealing with. Any help or suggestions of where to start. I already changed the oil and it does have compression. Thanks in advance.
Jeremy

[wisch79]

[John *.?-!.* cub owner]

We used to have one set up the same way. + side of battery to frame of engine, other side to coil, + terminal of coil to points, and high voltage wire to spark plug. If the - terminal of battery is to frame, then reverse the coil connection.

[wisch79]

That makes some sense. Where do I find the wire to the points? I have not taken the points out yet, so that may be obvious. If so sorry for asking. I have been doing more research and I believe the mag is an H1 and many say that it is the same as an H4 like found on tractors, at least the points and condensor. I think I am going to tractor supply tomorrow and see if they have the points and condensor there. Is there any way to check and see if the coil on the mag is good? In doing some testing tonight, I found the one wire on to is grounded and the other is not. The wire on the outside of the mag(orange in pictures) is a grounding kill wire. Is this correct? Thanks so much for the help!
Jeremy

[Virginia Mike]

Many resources are available online, including owners manuals.
Try www.smokstak.com

[John *.?-!.* cub owner]

That makes some sense. Where do I find the wire to the points? I have not taken the points out yet, so that may be obvious. If so sorry for asking. I have been doing more research and I believe the mag is an H1 and many say that it is the same as an H4 like found on tractors, at least the points and condensor. I think I am going to tractor supply tomorrow and see if they have the points and condensor there. Is there any way to check and see if the coil on the mag is good? In doing some testing tonight, I found the one wire on to is grounded and the other is not. The wire on the outside of the mag(orange in pictures) is a grounding kill wire. Is this correct? Thanks so much for the help!
Jeremy

The outside wire would have been a kill wire originally (ground to kill the engine), but as it is now wired, that would be the wire from the coil. It connects to the points internally. About the only way to test the coil is to replace it, but more than likely the reason for the external coil is that it is bad. The good thing about it is that they are less expensive than cub mag coils. If you crank the engine slowly you should hear the impulse snap everytime it is supposed to fire (every other round for this engine). If it does not snap, you will need to repair that before using it as a mag.

[wisch79]

I think I understand now. Here is a quick picture I drew up. Does that look right? It does make the clicking noise every other rotation. Hopefully I can find the points and condensor tonight and maybe get some spark out of it. should I use a 6v or 12v coil and battery?

[Jeff Silvey]

Jeremy:
I have had engines for about 29 years. Let the people that rebuild or deal with mags help you. Here is a guy I trust very highly.
Marks Magneto Service.
( 860) 537 0376
Jeff

[Eugene]

Use a 6 volt battery. You can use a .33mf condenser (ask at autoparts store for a Chrysler ignition capacitor from a points operated ignition system or Radio Shack - $3 or $4- range). 33 mf is a ballpark figure - any thing close will work. You need to have the external coil grounded to the engine block. The condenser can be attached to the down stream coil post (usually negative) and grounded to the block. So don't buy a new magneto condenser just to get the thing running - just disconnect the magneto condenser.

My guess is that you can clean up the points enough to get the engine running. Add some kind of switch.

If you use a 12 volt battery you will need a voltage drop - resistor - to get close to 6 volts at the points.

If you are familiar with how automotive points operated ignition systems work and are set up - you can use the same general outline. Yours is pretty close.

[John *.?-!.* cub owner]

wisch, you have the basics.

[wisch79]

Thanks for all the help guys! I went tonight to tractor supply and bought a tune up kit for a H4 mag. New points and condensor. Cleaned and installed all that and nothing. I could not figure out what the problen was so I took the 2 screws out that held the mag coil on and took it out. Bingo! I now had bright spark out of the external coil. Pulled the spark plug, cleaned and gapped it, and had great blue spark there. Poured a little gas in the cylinder and installed the plug. Gave it a few spins and she sputtered. I kept plaing with that and could get it to hit only a few licks at a time. The engine is missing the flip out handle so trying to spin it by holding the flywheel wasnt easy. It did seem like it was gaining compression as the night went on because it got harder to spin on the compression stroke. Now I need to take the carb off and clean or rebuild it and hopefully find a handle and then I will be in business. Once again thanks for all the help!
Jeremy

[Virginia Mike]

Jeremy,
No carb, just a mixer. Spray cleaner in the hole the adjustment screw is in, and the fuel line inlet. There is a check ball in the fuel line in the tank that must be free. That's all there is to the fuel system.

[John *.?-!.* cub owner]

If the internal wire was still connected to the original coil that would have kept it from firing on the external one. I learned that the hard way once.