Tecumseh Solid State Ignition troubles. Magneto?


Old 01-05-08, 11:58 AM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
Tecumseh Solid State Ignition troubles. Magneto?

Here's the story:
I have a Bolens 1055 G-10 with a 10HP Tecumseh HH100.
Last year, at the end of the snow season, I had a small fuel leak where the pulse pump screws into the carb. I took off the assembly, broke both parts down and cleaned them up, then put back on the engine.
Needless to say, it hasn't ran the same ever since.
The engine would start right up, but after running for 5 minutes it would start acting up, like it was running out of fuel or choking out. I took the carb assembly back off and repeated the cleaning.
Still wouldn't run right.
I'm a disabled Vet and with all the snow we have been getting here in Wisconsin this year, it has been pretty hard on me trying to get at it with a shovel.

Anyway, I was convinced that the problem was in the fuel pump which is a Walbro pulse pump. I couldn't locate a new Walbro, but did find an aftermarket pump. Once again, I took the carb apart and cleaned it up good. I cleaned the gas tank, put new lines on and crossed my fingers.
The engine started right up and sounded good.
I let it warm up while I went inside to dress for snow blowing. Probably a good ten minutes passed before I climbed on board and put it in gear.
I made about 4 passed on the driveway, then it started acting up again just like before. .

It took alot to get it back into the garage.
It just wouldn't run right for me anymore, and now I can't even get spark.
I bought new plug, still no spark.
I'm about at my wits end here, but know that when I get this thing figured out, it will be a fine machine again.

There is a solid state ignition and I have no idea how to get to it and check it out. Here's where I need help.
The only exterior components are the starter, selenoid and voltage regulator. There is no coil.
I don't know a thing about a magneto.
Do I have to take the whole flywheel off the engine to get to the magneto? It looks like there is a cover that I might be able to get off. This cover has a hole on each end for the fuel line to come in and out of because the tank is on the opposite side of the carb.

Once I can get help getting at the magneto and instruction on how to check it out, then I can at least have a good starting point again in figuring out the rest of the problems.

Another thing is the Carb. I don't know what kind it is. Since the pump is Walbro, should I assume the carb is Walbro as well?
The following numbers are stamped onto the carb: 4664 23 240 38. The only words I found were on the float bowl and that said Lauson Co. Grafton, WI.
I need to figure out what I have so I can get the proper rebuild kit. Everything did look good inside the carb if that matters, and the new fuel pump is pumping fuel to the carb.
One thing I couldn't figure out is there is only one screw pin on the bottom of the float bowl. If this is the high speed, it didn't change rpm's when I turned it in or out . I started with the basic 1 1/2 turns on both idle screws.

Help? Please?
Rob from Fond du Lac, WI
Sponsored Links
Old 01-05-08, 05:31 PM
Join Date: Jan 2008
Posts: 1
The first thing with the running for five minutes and then stopping sounds to me like the gas cap was not venting.

The spark issue could be that you have a wire that is grounding out someplace. I would check to see if any wires are contacting any metal.
Old 01-05-08, 07:04 PM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
Not Gas Cap

I made sure the vent was open, so it's not the gas cap.
So far tonight I took the gas tank off so that I could get the fuel line from the flywheel cover.
I got the cover off and see a unit with a wire that goes behind the flywheel. There is another wire coming back out from behind the flywheel that is screwed onto the side of the engine. Would that wire be a ground? On the same clip that the wire from behind the flywheel is attached to there is another wire that goes to the area where most of the other wires are, like the solenoid and voltage regulator.
I don't know if that is just a ground or not. The clip that is attached to the side of the engine looks like it is supposed to have two wires on it, but I really have no idea what it is for and how many wires should be attached to it.
I printed the wire diagram, so I will be going over that yet tonight to get an idea of what and where the wires are for and where they are supposed to go.

I guess the next step is to get the flywheel off to reveal what's behind it and what the wires are about.

Question - After I have the flywheel off, what should my next step be?
I will post a description of what I find.

I really need to find out what my Carb is so I can get a rebuild kit and get that out of the way.
Is there somewhere I can look at carbs to try and determine what I have?

Thanks again.
Old 01-06-08, 10:30 AM
Join Date: Sep 2007
Location: Cottage Grove, MN
Posts: 239
Write down the engine's model and serial numbers, and even a carb number if it is present. Take these numbers to a local small engine shop and they (based on model number of engine) should be able to get you the right kit. Just make sure you go to a Tecumseh dealer and get a genuine Tecumseh carb kit as the aftermarket kits tend to be junk.
Old 01-06-08, 01:08 PM
Join Date: Mar 2007
Location: Southern Wisconsin
Posts: 354
It appears that your engine is old enough to still have breaker points due the the wires behind the flywheel. You will need points and condensor if you are going that far. When the engine stopped did you check for spark? Remember you fuel, spark and compression to make it run.
Old 01-06-08, 09:29 PM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
More wiring details

I went through the wire diagram last night and all looks good.

There is a Blue wire that runs from the Ignition Switch to Stator. What is the Stator?
The end that goes to the Stator is connected to a clip that is attached to the flywheel housing. Another wire (attached to same clip) goes behind the flywheel.
The wire that comes back out from behind the flywheel is attached to what looks like a Pulse Transformer. At least that's what the picture looks like. Then the High Tension Lead coming from the Transformer is the spark plug wire. On the back is a number #71984 and says Mexico.
The diagram I am looking at that has the drawing of the Pulse Transformer, shows a wire leading to another component with the following: Low Tension Lead; Trigger Pins
and Magneto.
Can anyone give me the low-down on these?

I got the big nut off of the Flywheel Spool but haven't got the Flywheel off yet.
Is there anything else I need to remove in order to get the Flywheel off? It isn't coming off easy and I don't want to risk damaging it.

After I remove the flywheel, I will at least be able to tell what's behind it and hopefully solve the spark problem.

Is there even a way to check for spark with the Flywheel and starter belt removed?

I bought a Universal Spark Tester today to help with the test.

With this new info, do you still think there are points and condensor?

Old 01-06-08, 10:42 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 17,118
Upvotes Received: 14
Yes, it does sound like you have points and condenser, and I would suspect that is the cause of your problems. I suggest using a flywheel puller to remove the flywheel, or a little gentle prying with a rap on the end of the crankshaft with a hammer (have the nut flush with the end of the shaft and be careful to hit squarely and sharply while not damaging the crankshaft). Keep track of the flywheel key, and do not lubricate or grease or apply anything at all to the area where the flywheel mounts when you reinstall it, and be sure to torque the flywheel nut sufficiently.
Old 01-10-08, 01:08 AM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
Solid State Ignition troubles (Flywheel Off)

I have the flywheel off.
There are no points or condensor.
The diagram I am looking at is for the Solid State Ignition
(Not) equipped with flywheel alternator.
Fig. T61

The Magneto and the piece with the two triggering pins are both on a mounting plate, and the Pulse Transformer is mounted above both.

Starting with the Magneto, there are two wires. One wire is grounded to the mounting plate. The second wire is also attached to the mounting plate with another connector. From the connector, the wire then goes to a clip that is attached to the Flywheel with another wire that comes from the Ignition switch. (Blue Wire) on diagram says (To Stator).
The piece with the trigger pins has another wire that leads to the Pulse Transformer, then becomes the Plug Wire.

The part I'm still confused on and haven't gotten an answer for yet, is, what is the Stator? The Blue wire from the ignition switch is supposed to go to the stator, but I don't know where it is.
The Blue Wire like I said, goes to a clip on the Flywheel Housing. Is that the Stator?

How can I test the components to see if they are O.K.?

I tested the wires with an OHMeter and showed continuity through the whole assembly.
The Magnet has good pull.

Since I have the engine broken down this far, is there Any Advice on what I should do next? Or anything else that should be done.
I sure would appreciate any help. I would really like to get this thing back on the road before our next snowfall.

I'm also cleaning everything up real good for when I reassemble it all.

Maybe I'll get lucky and what it needed was a good cleaning? Or is there another problem that I don't know about?

Thanks Guys.
Rob in Wisconsin.
Old 01-16-08, 08:16 AM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
Still looking for help

I haven't gotten an answer yet from my last post and was wondering if there is anyone out there that can help me?

Is there a way I can test the magneto, Pulse Transformer and Transformer assembly?

If you go to link I provided, Fig. T61, you can see exactly what I have.
It says the Magneto charging coil, electronic triggering system and mounting plate are available only as an assembly.

Are any of these something that would just stop working?
There is plenty pull on the magnet.
And again, does anyone know what the blue wire that runs from ignition switch to Stator is for? Is there supposed to be power to this or a ground? I put the wire tester on it but shows no power through wire.

Rob in Wisconsin
Old 01-16-08, 09:43 AM
Join Date: Jan 2007
Location: MA
Posts: 515
I cannot get link to open
Old 01-16-08, 01:14 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 17,118
Upvotes Received: 14
Ok, you have the oddball engine Tecumseh made as one of their early (maybe the first) attempts at solid state ignition. It actually worked pretty well, but it's more complex than necessary.

I have limited experience with these...there just aren't many around. Bear with me, and I'll give you whatever help I can. The stator is generally the alternator, and since yours is not alternator equipped, it would not have the stator.

I have seen two ignition failures on these engines before. On one, the trigger coil had a break in the coil windings. I determined this with an Ohmmeter, checking the resistance between the wire terminal and ground. It was an open circuit, but should not be.

Another time, I got a signal all the way to the transformer, and still no spark, so we replaced the transformer (was hard to find one, and expensive) and it worked. I don't remember how I checked for the signal, but I'm sure I used either a test light or voltmeter to watch for pulses of current while the engine was cranking. If you get these pulses, then the trigger part of the system is working.

I hope that helps some. Let us know what you come up with, I'm sure we can get this thing fixed.
Old 01-16-08, 05:54 PM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
Solid State Ignition

Thanks Cheese.

I guess What I'll do is
inspect all the wires for cracks in wire and insulation.
Check for current with Ohmmeter.
The trigger coil, is that the top piece of the assembly with the two trigger pins?
Is the wire terminal on that piece what you are talking about? So I would check for current with positive on terminal and negative at a ground? And there should be no current?

And then I will test the Pulse Transformer by checking for pulsing current at the transformer?

O.K. So one last time on this blue wire that runs from the Ignition switch. I still don't understand what the purpose of it is since there is no power at the switch terminal.
Should there be continuity from the switch terminal all the way through the Magneto assembly and through the Transformer to the end of the spark plug wire?
Or could you try and explain what I would look for throughout that whole line of connections?

I am sure I will have to work on the carburator yet, but I want to get this spark thing figured out first.

Is it possible I burnt something up when I was trying to start it up the last time? Can you burn something up by turning the engine over with no spark?

Thanks for getting back to me.
I am going to get this thing back together tomorrow because we have yet another snow storm coming tomorrow morning throughout the day.

I really need to get this thing working because it's pretty hard on me getting the snow shoveled because of disabilities.

Wish me luck and I will post to let you know what I find out.
Old 01-16-08, 06:22 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 17,118
Upvotes Received: 14
Ok, look at fig T62 (a more explanatory version of FigT61). At the wire between number 7 and 8, you should get a pule with the voltmeter set in DC mode, with the positive electrode connected to the unplugged wire, and the negative on ground/frame. You're looking for an electrical pulse coming from the trigger coil assembly.

I can't tell about the blue wire...I don't have a wiring diagram for the machine. Look on the back of the switch and see what letter is on or next to the terminal where this blue wire connects on the switch. It may be stamped on the terminal itself. This will help identify what the purpose of the wire is.

Let us know what you find.
Old 01-16-08, 10:12 PM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
Ignition Switch


Here is the wire diagram for my Bolens.

I've already went through the entire wire harness to make sure that it is exactly as the diagram shows, and it is.

So the blue wire, the infamous, mysterious blue wire, screws to the (D) terminal, then connects with the magneto/trigger coil assembly via the clip on the Blower Housing Baffle, then to Pulse Transformer/Plug wire.
I have no idea what any of the letters stand for, so if you could enlighten me there, I would appreciate that as well so I can write that down on my diagram sheet.

Correct me if I'm wrong here but I'm assuming that the two safety switches wouldn't have anything to do with spark? I know the starter won't turn unless the pedal is depressed and the attachment lever is in the off position.

I had the pedal depressed with a brick while I was trying to test wires, this was when there was still intermittent spark. The brick slid off and the pedal slammed back up fairly hard. It was shortly afterward when I realized I wasn't getting spark any longer.
Just coincidence? Or would this effect my spark?

Thanks Cheese
Rob in Wisconsin
Go Pack Go!!!
Old 01-17-08, 02:06 PM
cheese's Avatar
Forum Topic Moderator
Join Date: Jul 2001
Location: USA
Posts: 17,118
Upvotes Received: 14
That switch doesn't have the normal letter designations for the terminals that normal lawn equipment switches have. I don't know the meaning of those letters, other than B is for battery pos, and S is for solenoid trigger wire. The blue wire is just shown to be coming from the D terminal, and goes off the page. There isn't another page showing the destination of the blue wire? It says stator. That could mean a few things, since stator doesn't necessarily mean one specific thing (it normally means the alternator when dealing with more modern engines. On this, it could be any plate or assembly with induced electrical windings.) Does the end of the blue wire have a connector on it? Does it look like it's ever been connected to anything? Look at the bends in the wire, and the length, rub spots, etc... that might lend information to how it was routed and where it connected, if at all.

The diagram you have doesn't show the safety switch configurations, (unless figures #60 are showing the entire function of the switches) but I would guess that they do indeed control the ignition as well as interrupt the starter solenoid. Look at the green wire going to the 2 safety switches shown as #60. Are they the only 2 wires going to these switches? If so, then I guess the ignition is not affected by them, but if not, then it may be. There may also be other switches that could affect the ignition independently of those 2 switches. There could be a seat switch to shut off the engine if you fall off the seat, a clutch switch, a pto switch, and a neutral safety switch.

If you have more diagram than the page you linked to, show it too. That's where a lot of the missing info will be.
Old 01-18-08, 10:40 AM
Thread Starter
Join Date: Dec 2007
Location: Wisconsin
Posts: 14
Safety Switches


The two safety switches have two wires. One going in then one coming back out to complete the circuit leading to the starter, so that's not a problem there.

My unit doesn't have a switch under the seat either.

I didn't get it back together like I wanted to yesterday. Neighbor came over and helped with the snow.
Now it's just too damn cold to do anything out in the garage. I think I'll look for a wood stove for next year.
It's only getting colder. We'll be lucky to get above 0 this weekend.

I'll get back in a few days after I get it back together.


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Display Modes