Lost my (ignition) spark

Reply

  #1  
Old 05-18-04, 03:20 PM
Member
Thread Starter
Join Date: Jul 2003
Location: kansas city MO
Posts: 103
Lost my (ignition) spark

It wasn't much to start with (pun intended), but it was all I had.

My push mower (3.5hp B&S*)has been dieing under heavy load, and it is then difficult to restart. Spark was real weak and plug terminal was real loose. Tightened terminal, gapped plug .030, set points to .020. Adjusted coil to about .003 and now no spark at plug or at plug terminal. Capacitor not shorted to case. Coil resistance is zero (is this normal?), and no shorts in primary kill circuit.

Just discovered that coil gap should be .006 to .010, and am leaving now to adjust. Am still worried about zero resistance across coil leads.

What next?

*model 92902, type 1241, trim 02, code 82032501
 

Last edited by SKIP; 05-18-04 at 04:07 PM.
Sponsored Links
  #2  
Old 05-18-04, 04:21 PM
Member
Thread Starter
Join Date: Jul 2003
Location: kansas city MO
Posts: 103
Set the coil gap to .009 and still no spark. Resistance across coil leads is zero, and there is no short from either lead to ground. I'm suspecting the capacitor, 'cause when I pulled the plug I laid it on the head (reconnected) and turned the engine over, and got a small white spark - at first. After turning it over 2 or 3 times, the spark dwindled down to nothing. Placing just the plug terminal next to the head also results in no spark. I removed the capacitor and checked for physical damage, and noticed a small drop of dried wax on the end, at the seam between the case and the hermetic end seal.
 
  #3  
Old 05-18-04, 04:21 PM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
Negative good buddy

There should be approximately 100 ohms of resistance between the primary and secondary windings, which means you need a new coil. May I suggest a solid state replacement rather than the old-style point ignition coil. The new Briggs part number will be 496914 for solid state, the original coil part number is 298502, if, for some reason, you wish to stay with the points & condensor. Coil airgap is .010", with either.
 
  #4  
Old 05-18-04, 04:33 PM
Member
Thread Starter
Join Date: Jul 2003
Location: kansas city MO
Posts: 103
I was thinking of replacing the points/condenser with a solid state unit, but I thought that I would still need the coil. Do I? Or am I just misinterpreting?
 
  #5  
Old 05-18-04, 04:48 PM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
The 496914 coil is all-in-one unit, this IS the only component you will need. It looks similar and mounts exactly the same as your current coil, just do away with the pts & cond. Be sure to fill the plunger hole with the supplied plug (that comes with the new coil).
 
  #6  
Old 05-19-04, 10:01 AM
Member
Thread Starter
Join Date: Jul 2003
Location: kansas city MO
Posts: 103
puey61 "There should be approximately 100 ohms of resistance between the primary and secondary windings..."

I priced that 496914 coil, and it's $32.96 + tax. In the meantime, I measured my old coil to make sure we're talking apples and apples. I'm getting 0 across the primary, and about 2800 across the secondary. This morning I checked the coil on a known good engine, and it had the same values (plug terminal to condenser terminal, or plug terminal to ground terminal, either way). So where would I find the 100 ohms?
 
  #7  
Old 05-19-04, 05:03 PM
Member
Thread Starter
Join Date: Jul 2003
Location: kansas city MO
Posts: 103
Seem to be talking to myself. This afternoon I bought a new condenser, and it solved the problem (old coil still in place). Felt so good, I put in a new plug too. If this keeps up, I might even spring for an air filter.
 
  #8  
Old 05-19-04, 08:24 PM
Sharp Advice's Avatar
Admin Emeritus
Join Date: Feb 1998
Location: The Shake and Bake State USA
Posts: 10,440
Smile Lost Spark.....Now Found

Hi: Skip

No. You are not talking to yourself.

I have been reading this post also...

Glad you did not lose your "SPARK"....LOL!
That would be a problem this forum could not solve....

YEP! No ignition spark on an engine with points and condenser, suspect the condenser second. The ignition kill switch first.

A grounded switch will cause a no engine "Spark" condition. (In the ignition)
Since there was a tiny spark, as you indicated, real good chance the condenser died.

Glad the "No Spark" problem is fixed.

Buy that air filter. You'll be glad you did.

Check and or change the oil too.

Regards. Sharp Advice.
Master Small Engine Tech. Web Site Host, Forums Monitor and Multiple Topics Moderator. "Accurate Power Equipment Company." Engine Diagnostics Services & Repair. Fast...Fair...Friendly & Highly Proficient Services....
 
  #9  
Old 05-20-04, 08:20 AM
Member
Thread Starter
Join Date: Jul 2003
Location: kansas city MO
Posts: 103
Sharp Advice

Yep, the first thing I did when the spark went away was take apart the kill switch circuit and clean all the parts and reassemble and check.

For sure, I'll get a new air filter - at the time, I didn't want to throw good money after bad, in the event I couldn't get the mower going. I keep my air and oil clean, and my blades sharp. Sometimes it seems my equipment gets more wear from maintenance than from use. So what! I enjoy both.

What disturbs me about this episode, is that the guys down at the shop, all certified and experienced and all, seemed to have no intuitive ideas about my problem, and said their computer didn't cover machines that old, which prevented them from giving me any advice. I'm not knocking training or certification, but where does aptitude fit in?
 
  #10  
Old 05-20-04, 03:45 PM
puey61's Avatar
Member
Join Date: Apr 2004
Location: Upstate New York
Posts: 3,224
Service Centers

I'm glad you got the trouble resolved, but I'm sorry you had a bad experience at the shop you went to. Being a shop owner myself, let me first say how difficult it is to find competent, qualified technicians in this industry. There simply isn't enough out there. Most kids going through school just don't consider taking courses related to our industry. Hell, why would they...relatively low pay, dirty work, small chance for good benefits, less chance for moving up the company ladder and the list goes on. They'd rather go on to college and get in to a computer related field and reap the rewards.

Hopefully, you have another option as far as shops are concerned so that you can find someone who has knowledge and the friendly advise you're looking for now and in the future. Maybe too, if they're anything like our shop, the persons' head was swimming from the onslaught of calls, walk-ins, scheduling and technician inquiries, among other things which we deal with every day this time of year. This is our break-neck-paced season and we do sometimes forget to be nice and curteous and give each individual the time they deserve on occassion. Perhaps giving this shop another chance might pay off.
 
  #11  
Old 05-20-04, 04:31 PM
Sharp Advice's Avatar
Admin Emeritus
Join Date: Feb 1998
Location: The Shake and Bake State USA
Posts: 10,440
SKIP

Slightly off topic but worth the brief discussion. (IMO)

Moderator puey61 is correct on all points. I agree fully.

Additionally, problem is, two folded.

1)
Field experience.
2)
"Thinking Out Of The BOX"

#1 & #2 above pertaining to some machanics, certainly not all, depending too much on school training, books and now computers.

Thinking out of the box is or is about to be lost forever, as a means of determining a simple problem with a single cyclinder engine.

Thinking out of the box is not taught in schools, classes, books and or computers. However, it was taught in my classes which I gave...

No additional charges either...LOL!....
 
Reply

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