Help with antique Briggs & Stratton?

[mingv]

I've got a 1958 Briggs & Stratton 6B-S engine I'm trying to get running. I seem to have good compression (thumb in sparkplug hole test). I've got fuel dripping in the carb. I've got a new Champion J8 sparkplug gapped to .020". Still won't start.

Two things occurred to me:

(1) the plug doesn't look wet with gas when I remove it after several pulls on the rope starter. But I've got fuel in the bottom of the carb, to the point where it's dripping out the hole for the air cleaner screw. So I _think_ it's getting gas, but I'm not sure. (I've also tried spraying the intake with "starting fluid" to no avail.)

(2) I've got a spark when I lean the plug against the head, but it seems very weak. I think this is my problem rather than gas. I removed the sheet metal that covers the flywheel. DOES THIS THING HAVE POINTS??? If so, I can't find them. The spark plug wire comes out of a black thingie that I can't seem to get into. Is this a magneto? (I don't understand magnetoes.)

The thing that really worries me is that coming out of this black thingie (magneto?) is a blue wire that hangs down on the outside of the motor and doesn't connect to anything, and there's a red wire that comes up from inside the motor case, comes up close to the black thingie (magneto?) and DOESN'T CONNECT TO ANYTHING. Should either or both of these wires be connected to something???

I'm at a loss. I've spent a couple of hours on the web trying to figure this out, and been all through my "Walking Lawn Mower Service Manual" (which only seems to deal with more recent models). My local mower shop is closed on weekends and I'm leaving town early Monday morning. So I'm hoping I can find some help here.

Thanks in advance!

[Boots]

[ds549]

there are points under the flywheel, you can sandem with some emery or replace.

[meAT]

Won't start and "won't fire" is different to me. Does the engine fire (act like it's about to run) at all? By "fuel dripping", do you mean "flooded" - with fuel coming out or do you mean you see or know fuel is getting through normally.

Have you cleaned the carburetor, by that I mean checking to see if the carb float is stuck or sticking. Besides the cleaning the jets and float, etc, there are "two very small holes" inside the "tubby thingy" that may be clogged and preventing adequate fuel from getting through. The way to clean them is by using a steel bristle (tiny wire) from a steel brush to clean them out. They do get clogged

You can poor a small amount of fuel in the plug hole, replace the plug and see if it fires. If so, you may not be getting enough fuel, so check the holes mentioned above, also if the carb (not sure) a diaframe (sp) , it may be week or bad.

You prefer a strong solid "blue" spark verses a week yellow or orange one.

No point's. With sand paper, clean (lightly sand) the magnets of the side of the flywheel to remove any rust or film build-up. See if this improves the spark test. Make sure the wire is snug on the plug when attached. Also sand the metal portion (adjacent the fly wheel) of that black thingy so when the fly wheel rotates there is good contact.

If the card checks out and is cleaned as mentioned it could be the black thingy needs replaced....but my first guess is the carb jets, etc.

Can you determine if something is missing. I don't recall older engines having and off and on switch.

Oren

[Ulysses]

That seems kinda tight to me. Is that what is on the specs? I would try ..032.

You probably have to pull the flywheel to get to the points (use a flywheel puller, don't bang on it or pry it off). I would (without specs) try .015 as a starting point to set the points.

The spark plug wire comes out of a black thingie

I think you are describing the coil. There is a magnet on the flywheel that causes induction each time it passes the coil.

One of those wires (usually black) might be a ground wire to shut of the engine. It should run without that attached as long as it's not shorting out. You also have a condensor in there but it should only have one wire attached to it and the case is grounded. But since you say you have spark then your points must be opening and closing. It is possible that you have a bad condensor or a weak coil. Sometimes the magnet on the flywheel can become weak over time but that doesn't seem likely.

As someone else said take out the spark plug, pour in a tiny amount of gasoline, and try to start it. If it runs briefly then you probably have a clogged carburator. This is the most likely problem because if old gas gets left in there it will almost certainly clog it.

[mingv]

Oops - typo! I meant .030" (what my mower repair guide says)

[Stormin Mormon]

Dear Oren, I've worked on a bunch of old Briggs engines -- I'm fairly sure they do have breaker points. To get at them, you'd have to knock the flywheel off, and take the little aluminum cover off.

[mingv]

I originally mis-typed .020" - so yeah, his comment about being too tight was right on.

[Steve B.]

You have to have the screw for the air cleaner in the carb or it won't run. If the screw is not there it will pull gas through that hole and flood. This probably is not your problem now though....

There are points up under the flywheel on top of the motor. You remove the starting assembly (did they have recoil back that far?) and then use a flywheel puller to pop the flywheel off and you will find the points and condenser under there. You will also find a key between the flywheel and crankshaft that shears off if you hit something with the blade. Check to make sure it is in perfect shape and not sheared any as this will throw the timing out.

Points should be the same ones you will find on the shelf at the Home Depot. One of those wires should run from the points to the coil. Once you pull the flywheel you should find that wire and be able to see where it goes.

Good luck getting the old girl running again. Sounds like a fun project.

Steve B.

[Don]

Check out the Small Engine Technical Forum at:

[Stormin Mormon]

Hey, Boots. The OP said it owuldn't work on a squirt of ether. And the spark is weak. Sounds like it's not fuel.

[Stormin Mormon]

I've got fuel dripping in the carb. I've got a new Champion J8 sparkplug gapped to .020". Still won't start.

Two things occurred to me:

(1) the plug doesn't look wet with gas when I remove it after several pulls on the rope starter. But I've got fuel in the bottom of the carb, to the point where it's dripping out the hole for the air cleaner screw. So I _think_ it's getting gas, but I'm not sure. (I've also tried spraying the intake with "starting fluid" to no avail.) CY: The ether test indicates it's not a fuel problem.

(2) I've got a spark when I lean the plug against the head, but it seems very weak. I think this is my problem rather than gas. I removed the sheet metal that covers the flywheel. DOES THIS THING HAVE POINTS??? CY:yes, the poiints are under the flywheel.

If so, I can't find them. The spark plug wire comes out of a black thingie that I can't seem to get into. Is this a magneto? (I don't understand magnetoes.) CY: The black thing is the ignition coil.

The thing that really worries me is that coming out of this black thingie (magneto?) is a blue wire that hangs down on the outside of the motor and doesn't connect to anything, and there's a red wire that comes up from inside the motor case, comes up close to the black thingie (magneto?) and DOESN'T CONNECT TO ANYTHING. Should either or both of these wires be connected to something??? CY: Typically there are two wires that come from under the flywheel. I don't remember the colors. One goes to the igniton coil "the black thing where the spark wire comes out" and the othe goes to the killswitch which is typically on the carburetor.

I'm at a loss. I've spent a couple of hours on the web trying to figure this out, and been all through my "Walking Lawn Mower Service Manual" (which only seems to deal with more recent models). My local mower shop is closed on weekends and I'm leaving town early Monday morning. So I'm hoping I can find some help here. CY: You'll have to remove the flywheel to get at anything useful. You up to a flywheel knock off? I'll coach you if you want.

Thanks in advance!

[Stormin Mormon]

Well, sheez. THAT explains why his mower won't start. Creepers, the poor guy has probably been out yanking on the start cord for the last three days cause he over gapped his plug by .002, and you don't even apologize?

(I hope you find this as funny as I did while writing it. Some misteaks aren't worth correcting, they are so smell.)

[Ulysses]

What am I missing here? Did I say to gap his plug at .002 somewhere? I sure don't see where anyone said that...

On a modern BS engine it's usually about .032 for the spark gap. That's in inches.

[Oscar_Lives]

B&S plug gap spec is 0.030".

[meAT]

I stand corrected - had brain fart there. After reading again it started clearing up the cob webs.

Thanks,

Oren

[Stormin Mormon]

"overgapped by" means greater than. 032 is greater than 030 by.... 002.

[Ulysses]

I think I understand what you are saying now. You mean you think a BS engine would not start if it was gapped to .032 instead of .030? I don't think it would make any difference to the engine for short term. Many small engine specs range from .029-.032 which is more of a difference than you are saying won't work.