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DISREGARD - PREV OWNER FOUND THE MANUAL. THE MOWER IS MODEL 14SE.

Hi,

I have a 21" self-propelled JD lawn mower. Recently, the mower engine started surging pretty badly, then shut off. Now, the mower starts fine but shuts down after about 10-15 seconds of running.

It was just gone over and had an oil change at the beginning of this season. Filters are good, everything checked out OK.

I suspect that the part is what I *think* is a voltage regulator that is attached to the engine. It is a square device, about the size of a postage stamp, with an integrated mounting bracket (one small nut holds it on a stud) and a single 3/16 in. spade terminal. The back is black epoxy potting, and the part as "TI-36 JAPAN" inscribed on the front.

My issue is identifying this part so I can order one. My mower has a plate on it that provides what I assume to be a model number, which is JD902. Several John Deere parts sites, most of which refer / link to what I think is JD's own parts database, cannot find this mower. I believe it was purchased at a big box home improvement store but what I DO know is that it was NOT purchased at a JD retail store.

Any ideas as to A) what my mower is and B) what this part is?

Thanks in advance from the new guy.

BG

Sorry to say this, but after reading your post I don't think you should be trying to repair this mower. Surging is very seldomly caused by an electrical problem. With that said I'll go into teacher mode. If this is a push mower, you don't have a voltage regulator, they are used on units with either a battery or lights. If you still want some help you are going to have to do two things. First get the name and model and serial numbers for both the unit and the engine. Second, take some pictures of the parts you are talking about. Sorry for being so blunt, but you must realize that we cannot see, hear or feel what you problem is. You must be our eyes and ears, and provide us with a better picture of what your problem is. If I had ten cents for every "thing" I was asked to identify or repair, I could buy you a new mower.

Rivets said:

Sorry to say this, but after reading your post I don't think you should be trying to repair this mower. Surging is very seldomly caused by an electrical problem. With that said I'll go into teacher mode. If this is a push mower, you don't have a voltage regulator, they are used on units with either a battery or lights. If you still want some help you are going to have to do two things. First get the name and model and serial numbers for both the unit and the engine. Second, take some pictures of the parts you are talking about. Sorry for being so blunt, but you must realize that we cannot see, hear or feel what you problem is. You must be our eyes and ears, and provide us with a better picture of what your problem is. If I had ten cents for every "thing" I was asked to identify or repair, I could buy you a new mower.

Click to expand...

No worries about being blunt and apologies for an incomplete post. I was frustrated and in a hurry and shouldn't have been.

First, the mower is self-propelled. It does have a battery but I think it's only used for the electric start, as I can manually start the mower with one pull, every time. I know this because the battery has not been in the mower for two years :smile:

Given that I figured out the model number of the mower (14SE), I was able to search John Deere's web site and identified the part. It is called an igniter (or ignitor), part number M77641. Two weeks before the mower started behaving as I described, something happened that makes me believe this part is at least contributing to the problem.

I was mowing a slope one day, and the mower began to surge. Then it began to stutter a bit, then stutter badly, until it finally shut off. 10 pulls on the cord and it wouldn't even attempt to start.

After pushing it back to the garage, I thought perhaps the problem was with or in the area of the air filter. As I went to check this, I noticed this "igniter" had lost its mounting nut and was hanging by the single wire that connects to it.

I put a new nut on, tightened it down, and voila, she started up on the first pull and ran fine until today.

Electronics being how they are, and with the epoxy potting making me believe that there is a small circuit board in this igniter, I think there is a chance that this thing has just worn out and / or had become damaged when it had begun to come loose and the connection was intermittent.

I appreciate your response and your concern - thank you. I was able to find a used and tested replacement on eBay for $25, which should get me through the rest of this season. That was a great find for me as I am currently out of work and didn't have $80.00 for a new one from my local JD dealer.

I'll post back with the results of the fix once I receive the part.

Thanks again for your response! :thumbsup:

BG

You said it started while cutting on a slope. That would indicate to me that the carb was higher than than the fuel source. I'll bet that you can replicate the problem again by mowing the same way, if you have a low fuel level in the tank. Inclines should always be cut with the carb lower than the fuel source.

Well, that makes perfect sense, except for the fact that A) I've mowed this slope the same way for three years now with no issues, and B) the mower now, while sitting on a flat surface (my garage floor), will start and run fine - for just 15 -20 seconds. This happens on every pull.

Quick question, what does this ignitor thing actually do? It must be related to spark because the mower will not run when it is disconnected. Ignitor sounds akin to ignition . . . . does this thing create the necessary voltage for the spark plug to work?

The ignition module, you call ignitor, controls the spark. Still say it is a fuel problem and believe the carb and jets need a good cleaning.

Rivets said:

The ignition module, you call ignitor, controls the spark. Still say it is a fuel problem and believe the carb and jets need a good cleaning.

Click to expand...

...........................+1

+2 amusing thread, sounds like carburetor cleaning is needed as well. low fuel issue as well.

This thing you call the "igniter" sounds like a condenser. This simply absorbs the "spare" energy created by the coil. I agree with the other responders, this is a carb issue. The fact that you have done this slope before means nothing. The mower is older now, the carb is probably a bit dirtier and the fule level was probably different. Another thing. When you mow on a slope, the gas in the tank gets shaken up and, regardless of any filters in the fuel tank or fuel line, dirt does get into the carb. On a flat surface, the gas intake is usually a little above the floor of the tank where the dirt accumulates. Clean the carb.

bgettel said:

DISREGARD - PREV OWNER FOUND THE MANUAL. THE MOWER IS MODEL 14SE.

Hi,

I have a 21" self-propelled JD lawn mower. Recently, the mower engine started surging pretty badly, then shut off. Now, the mower starts fine but shuts down after about 10-15 seconds of running.

It was just gone over and had an oil change at the beginning of this season. Filters are good, everything checked out OK.

I suspect that the part is what I *think* is a voltage regulator that is attached to the engine. It is a square device, about the size of a postage stamp, with an integrated mounting bracket (one small nut holds it on a stud) and a single 3/16 in. spade terminal. The back is black epoxy potting, and the part as "TI-36 JAPAN" inscribed on the front.

My issue is identifying this part so I can order one. My mower has a plate on it that provides what I assume to be a model number, which is JD902. Several John Deere parts sites, most of which refer / link to what I think is JD's own parts database, cannot find this mower. I believe it was purchased at a big box home improvement store but what I DO know is that it was NOT purchased at a JD retail store.

Any ideas as to A) what my mower is and B) what this part is?

Thanks in advance from the new guy.

BG

Click to expand...

This is rather late to reply, but I have the same mower and issue and this might help some other folks....

The TI-36 device is JD #M77641, "Igniter". I had the same surging, stumbling and quitting issue. Cleaned the carb, fuel flow, etc. The device failed intermittently so if you moved the wires it would sometimes run normally. I fiddled with various things until I fatigued and broke the connector...

Long story short, the replacement is available but hard to find at the John Deere website:

It is #31 on this diagram at jdpc - https://goo.gl/sqZxLp (MP7642)
Source page - https://goo.gl/H2S9yq (2097 - 14PB, 14PM, 14SB, 14SE and 14SM 21-Inch 4-Cycle Rotary Mowers - 13Oct03/alphabetical/I/Igniter) <note the date 130ct03!

It is $79 from Deere dealers or online from the usual sources at $9 (Rotary #9334), to $134 (Kawasaki #2119-2139).

OK,
Now we know what he is talking about.
This is the trigger unit.
It is nothing more than an "electronic" set of points + an advance/ retard unit in one little capsule.
Unfortunately many of these are unique to a particular engine.
You can use a universal replacement however you might find your timing is off and the engine may overheat so if you go down the aftermarket route, monitor the engine fairy carefully.

The chip cost around $ 1 so $ 79 sounds very rude.
Top shelf aftermarket ones will be marked as suitable for 2 strokes or suitable for 4 strokes so make sure you use a 4 stroke one.

A one terminal unit uses the metal case as the ground terminal and can be damaged when the ground goes bad as your did.
Without it in circuit you will get no spark.

This must be a very old engine as this unit got moved into the coil a log time ago which is why a coil is now called an "ignition module "