Old Briggs No Spark, 100 PSI Compression

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b52bombardier1

New Member
#1
#1
Hello,

I have an old B&S vertical shaft engine (3.5 horsepower) with no spark and a hundred PSI for compression. The model # appears to be 92902 1140 01 7606 1704 but I'm not certain this is the original pull starter.

What usually knocks out the spark on these engines? I believe this engine is too old for electronic ignition so I think I need to look at the points under the flywheel. The flywheel was a little rusty so I cleaned that off and the magnet still has good strength.

Would my instinct to look at the points be right??

Yes, it'll probably smoke when it starts but maybe the oil ring will free up to to do its job. And I was quite surprised that the fuel tank is not rusty.

Now to find a B&S flywheel puller . . .

Many thanks,

Rick
 
OND

OND

#2
#2
Yep ...your points probably need filed, sanded and cleaned...then I bet you have fire. Also set the point gap at I think .019 !
 
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b52bombardier1

New Member
#3
#3
Hello OND,

I have gotten the recoil clutch off the flywheel but I'm stumped after that as to how a puller can remove the flywheel. All of the puller apparatus that I can see online appears to need threaded holes in the top of the flywheel for the puller bolts to thread into. The top of my flywheel has no such bolt holes. What am I missing?

And I'm originally not far from you. I was born in Muhlenberg County - Greenville.

Many thanks,

Rick
 
OND

OND

#4
#4
How cool is that...Moma won't you take me back to Muhlenburg county !...well I'm not much of a singer...but anyway, so you got the blower housing off, and then the little screen bolted to the racheting assembly off ?



Is this what yours looks like ?
 
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b52bombardier1

New Member
#5
#5
Hello OND,

Yes, the recoil starter clutch is off and now that I have looked at a few YouTube videos, I think I can get that flywheel off without cracking that aluminum engine case. I will let you know very soon. The shaft has been soaking in some Kroil penetrating oil for about an hour.

Yes, that John Prine song about Mr Peabody's coal train is certainly true. I still get back there quite often.

Rick
 
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b52bombardier1

New Member
#7
#7
Hello OND,

Yes, a few light blows and it did pop right off. With the aluminum points cover removed, I used some 1000 grit wet-dry sandpaper on the points and cleaned up both surfaces. But still, no spark with the flywheel back on. I thought the points wire might be grounded but moving it a little did not help. I will try some rougher sandpaper tomorrow and see what happens.

On this style of ignition, can a completely failed condenser knock out spark? Or will it simply allow the burning of the points contacts? These points still look pretty good.

Rick
 
OND

OND

#8
#8
Hey after sanding the points ....clean the contacts with some alcohol and a lint free rag. And yes a condenser can kill spark ! make sure the points are closing all the way...and opening of course.
 
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b52bombardier1

New Member
#12
#12
Hello,

I checked the continuity of the coil from the points wire to the high tension spark plug lead and found that it HAS continuity. The two brain cells that I dedicate to small engine repairs tell me that this would be bad - failed coil. By my reasoning, I should not have any connection between the coil primary side (points wire) through to the secondary side spark plug lead.

So do I have a bad coil or do I need to look somewhere else? Are ignition coils for these engines still available?

Many thanks,

Rick
 
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b52bombardier1

New Member
#14
#14
Interesting video and I will definitely run that multimeter test tomorrow. It just seems to be an incomplete test though because it only tests the secondary side of the coil.

No check of the primary side of the coil was done.

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk
 
Outlaw Ace

Outlaw Ace

#16
#16
I'd use a solid state unit and avoid having to pull the flywheel altogether. I've done and it sure simplifies things and they can be gotten for a reasonable price, they bolt on and a standard business card placed between it and the flywheel is a great gapping guide. I've done it on more than a few briggs engines with much success and you have a post for a grounding kill switch right there on the unit so it also makes that easier.
 
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b52bombardier1

New Member
#17
#17
I guess the spacing for the mounting post is the same for either unit? Do you have a model number that you think would work for the solid state unit?

Thanks,

Rick

Sent from my SAMSUNG-SM-N900A using Tapatalk
 
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Havasu Dave

Moderator
#18
#18
b52bombardier1 said:
I guess the spacing for the mounting post is the same for either unit? Do you have a model number that you think would work for the solid state unit?

Thanks,

Rick
Click to expand...
It looks like part number 793281 is the magnetron replacement. Mag gap is the same- .010. Didn't intend to jump on Ace's good advice here, but was curious if anyone else had used this on your engine model. Some of the early Briggs flywheel magnets are opposite polarity and magnetrons wont work on them. (That's why I Googled the thing) :smile: (My disclaimer)

Ignition Coil for Briggs Stratton 591420 398593 496914 793281 793295 | eBay
 
Outlaw Ace

Outlaw Ace

#19
#19
I've used em on some pretty old engines but I'm sure you are right about the magnets on some older briggs engines. Best to hear all the opinions you can on a subject before spending money on something that may not work.

Havasu Dave said:
It looks like part number 793281 is the magnetron replacement. Mag gap is the same- .010. Didn't intend to jump on Ace's good advice here, but was curious if anyone else had used this on your engine model. Some of the early Briggs flywheel magnets are opposite polarity and magnetrons wont work on them. (That's why I Googled the thing) :smile: (My disclaimer)

Ignition Coil for Briggs Stratton 591420 398593 496914 793281 793295 | eBay
Click to expand...
 
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b52bombardier1

New Member
#20
#20
The price and the mounting post spacing certainly look favorable. Has anybody actually used one of these on a 3.5 horsepower vertical shaft engine? I am somewhat sure that the engine serial number is 92902 1140 01 7606 1704 but this recoil housing is probably not original to this engine.

Rick
 
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