1872 ignition and hydro problems

[OhioGuy]

I have a recently purchased 1872 that has two problems that I've spent a fair amount of time on, with limited success.

I'm intermittently losing spark. My neighbor loaned me a in-line spark indicator and the tractor will start 90 percent of the time, on that tenth attemp, no spark. I'm leaning toward the ignition module but that requires pulling the engine so I thought I'd ask here first and see if there is any other likely culprit.

There is a huge diagram of the ignition switch on the inside of the hood. A blind guy must have replaced it?

Maybe an intermittent PTO switch?

Maybe intermittent Oil pressure switch, could just unpug or jump that one?

The hydro problem is both pressure relief valves shooting a burst of oil on startup. I removed both and soaked in mineral spirits, put them back in and they seemed to be working fine. The next time I lost spark, it's guyser time again. But they were dry for a bunch of other testing.

The tractor is possessed, maybe I need a priest!

Curt

 

[JTKub]

Curt is this a single cyl or twin? Could you have a bad ignition wire, boot, etc? The coil/module could be the culpret. I wouldn't think this is safety switch induced since the safety switches typically dump power to the starter as well as kill ignition.

Joel

 

[OhioGuy]

Hey Joel,

It's an 18 Magnum twin. Instead of a coil, these engines used an ignition module that is mounted next to the flywheels and it times and generates spark. The module has the plug wires built right into it, seems like a bad idea but I've only replaced one in my 20 years of playiing with these.

But you gave me something elso to look at. I'm guessing when you turn the key off, it gounds that module. Maybe that wire is dinged and touching metal?

It's not heat related like the last one I replaced, you'd mow for an hour and it was like the key was turned off. Let it cool off and it would start right up.

I was sure I had it figured out this weekend when I was in no spark mode. unplugged a connector that the oil sentry passed through and it started right up. The next time I turned the key, no spark.

Curt

 

[art]

When people work on equipment often things get pulled and stretched while attaching new parts or inspecting tractors or even cars!

Id check every wire as to where it goes in and out of connectors. Give them a little tug and see if any are loose. Electronics could be bad, but I'd still check every possible connection first.

I'd say you might still have to replace those valves! It would be nice if tey would start working right but I've never seen them do what you are refering to.

 

[Fordlords]

The intermittent no spark smells to me all the way of a bad ignition switch. The Magnum's, "ignition module," is really nothing more than a magneto coil pack (hense the "mag" in Magnum,) and failure is usually only what you mentioned, it will get weak or no spark only after it gets hot.

I'm thinking of what is changing between when it works and when it doesn't. And the only thing that seems to be moving is that ignition switch, and they are very common troublemakers. I believe one of the sliders inside it has to complete a circuit to the primary side of the magneto.

There is also a small relay under the dash of the 1872. I don't know if this has anything to do with the ignition circuit, but relays are also prone to intermittent problems, so I'd trace there too.

For the hydro... The pressure relief valves are designed to pop off when the pressure is too high. As this is occurring at startup, something is making too much pressure in the hydro pump at that time. Look for there being too much fluid in the system, a plugged or the wrong filter installed, or dirty or too heavy (the wrong) hydro fluid being used.

Just tossing around some ideas

-Fordlords-

 

[OhioGuy]

The intermittent no spark smells to me all the way of a bad ignition switch. The Magnum's, "ignition module," is really nothing more than a magneto coil pack (hense the "mag" in Magnum,) and failure is usually only what you mentioned, it will get weak or no spark only after it gets hot.

I'm thinking of what is changing between when it works and when it doesn't. And the only thing that seems to be moving is that ignition switch, and they are very common troublemakers. I believe one of the sliders inside it has to complete a circuit to the primary side of the magneto.

There is also a small relay under the dash of the 1872. I don't know if this has anything to do with the ignition circuit, but relays are also prone to intermittent problems, so I'd trace there too.

For the hydro... The pressure relief valves are designed to pop off when the pressure is too high. As this is occurring at startup, something is making too much pressure in the hydro pump at that time. Look for there being too much fluid in the system, a plugged or the wrong filter installed, or dirty or too heavy (the wrong) hydro fluid being used.

Just tossing around some ideas

-Fordlords-

Fordlords,
Thanks for the insight on the ignition module, that makes sense.
I was thinking of jumping the ignition switch or just swapping with my other 1872.

I bought Hytran and a filter but thought I'd get the ignition corrected before moving on to that problem. I always replace all fluids on any machinery I buy, who knows what the last guy put in there.

Thanks for the suggestions!
Curt

 

[OhioGuy]

Well, all thats left is the painting. What seemed like a steal at the auction ($875) is closer to $1400 now with all the parts and fluids, but it's an awfully nice tractor.

The ignition problem was the module. On the Mag series the only thing that can prevent spark is the center ground lead on the module being grounded or a failed module. Since mine was intermittent, I isolated the ground wire and the next time it had no spark I started removing the engine and ordered a module, there went $100. But she's running great now. Nothing difficult about getting the engine out and back in, just time consuming.

The previous owner did a lot of shortcut fixes that took me a while to figure out/correct.

The air cleaner was held on with a coat hanger, stripped threads in carb.

The regulator had a lug burned off and the stator wire was just laying on top the motor, there went another $65 for a regulator.

The return spring for the starter had slipped over the top of the nut holding it. It was Sunday when I discovered that and Cub doesn't sell the spring, they sell a starter rebuild kit for $80 or so, so I went to my spring collection and found something awfully close. On this model, you need to remove the engine to service the starter, time will tell if I made the right choice there!

The hydro tie rod was actually held in place with a loop of bailing wire, he drilled a hole in the frame for that one.

The Mule drive latch was held in place with a tie wrap insted of the spring that was supposed to be there.

The 50" deck had the wrong blades on it, just a hair longer than the right ones so they would "tick" every so often when they hit. They had a keyed or star pattern around the bolt hole, anybody seen that before?

Wrong hydro fluid causing the pressure valve leaks.

Some of his fixes were very creative, and I've done my share of them also, but the Cubs all tuned up and ready to go now and it mows GREAT. I really like the 50" Cub decks!

So at $1400, not as good a deal as it looked like the day of the auction but if I have no regrets, I learned a lot and if I decide to sell, I'll have no trouble getting my money back and a little more.

Curt

 

[TractorLarry]

Look at it this way. You can't touch a tractor of that type for less than 5 or 6 grand these days, easy.

Sounds cheap to me

-Larry

Well, all thats left is the painting. What seemed like a steal at the auction ($875) is closer to $1400 now with all the parts and fluids, but it's an awfully nice tractor.

The ignition problem was the module. On the Mag series the only thing that can prevent spark is the center ground lead on the module being grounded or a failed module. Since mine was intermittent, I isolated the ground wire and the next time it had no spark I started removing the engine and ordered a module, there went $100. But she's running great now. Nothing difficult about getting the engine out and back in, just time consuming.

The previous owner did a lot of shortcut fixes that took me a while to figure out/correct.

The air cleaner was held on with a coat hanger, stripped threads in carb.

The regulator had a lug burned off and the stator wire was just laying on top the motor, there went another $65 for a regulator.

The return spring for the starter had slipped over the top of the nut holding it. It was Sunday when I discovered that and Cub doesn't sell the spring, they sell a starter rebuild kit for $80 or so, so I went to my spring collection and found something awfully close. On this model, you need to remove the engine to service the starter, time will tell if I made the right choice there!

The hydro tie rod was actually held in place with a loop of bailing wire, he drilled a hole in the frame for that one.

The Mule drive latch was held in place with a tie wrap insted of the spring that was supposed to be there.

The 50" deck had the wrong blades on it, just a hair longer than the right ones so they would "tick" every so often when they hit. They had a keyed or star pattern around the bolt hole, anybody seen that before?

Wrong hydro fluid causing the pressure valve leaks.

Some of his fixes were very creative, and I've done my share of them also, but the Cubs all tuned up and ready to go now and it mows GREAT. I really like the 50" Cub decks!

So at $1400, not as good a deal as it looked like the day of the auction but if I have no regrets, I learned a lot and if I decide to sell, I'll have no trouble getting my money back and a little more.

Curt

 

[Fordlords]

I ditto what Larry said, $1400 invested is not bad considering what it is. The Magnum was the last of the cast iron cylinder Kohlers, and the 1872 has features similar to the 3000's of today, yet still uses the IH style frame and transaxle. If kept in respectable shape, that tractor will hold its value for many years to come. Glad to hear you got things ironed out

I know I could never get the money back that I invested in to replacing the engine and deck on my 682 on top of the base-clear coat paint, but in knowing I will always hang on to the tractor I considered it an investment in myself. Even if on a purely logical level it was the silliest $2500 I blew in my life, I'll never feel or regret it.

-Fordlords-