Small engine repair/ignition

[saichele]

Although I am contemplating igniting the whole thing, I'd like to get this to work.

It's an old (20, 25 yrs?) Briggs and Stratton horizontal drive motor, mounted to a leaf vacuum. Got it for free from a barn, so the commitment is small, but it would be handy if it worked.

Didn't have gas in it, so the carb might not be gooey. I put in a new spark plug, shot a little ether in the carb, pulled the cord, and nothing. Took the pull cord off, sanded the flywheel off around the magneto, still nothing.

Anyone have a straightforward process for diagnosing/restoring beyond this? I don't necessarily want to drop a lot of money into it either.

Thanks
Steve

 

[quads]

Take the spark plug out. Hook the plug wire back up to the plug and lay it on the top of the engine so that the threaded part of the plug is touching (grounded) to the metal of the engine (cooling fins, other non-painted surface, etc.). Pull the cord and watch carefully for a spark across the electrodes of the plug.

If no spark, first thing try new plug.

If still no spark, second thing requires pulling the flywheel off and filing the points.

 

[mjbrown]

quads,
were the b/s engines still points ign. then or did they convert to the coil?

i had found and older b/s and it was coil ignition but i dont know what age it was...just saying. not doubting your post.definatly plug or ignition.

mike

 

[quads]

25 years old it's probably still points ignition, maybe not. Even if it's solid state, first thing check to see if it's getting spark. Could have flooded it bad enough to foul the new plug that Steve put in, so try another if no spark.

 

[Gooserider]

First, are you trying to get the motor running to use on something else, or are you after getting the leaf vac running?

I would agree on checking the ignition - do you have spark w/ the plug out of the engine?

I would also check compression - w/ a screw in guage, you should be able to get over 100-120 pounds after a few pulls - if not, pull the guage, put a shot of oil in the cylinder and repeat - if the results improve, you have bad rings, if not, bad valves. Either one suggests a need for significant repair work, which might not be worth it...

Once you get spark, and have verified that you have compression, it should be able to fire and run on ether for a moment or two.

If the engine sat for as long as you said, it may well have a really cruddy carb from all the gas in it evaporating after turning to gruk... Or the rubber bits may have dried out and cracked - it wouldn't hurt to try running a tank of gas and Sea Foam through it, but I wouldn't be surprised to see you needing a carb rebuild...

As an alternative, I know that Harbor Freight is now selling their "Greyhound" brand China Clone copies of the Honda engines for short bucks - sale price under $150 for the 6hp model, or they have Subaru-Robins for slightly more... In light of what you can get the Chinal Clone engines for, I'd hesitate to put a huge amount of work / money into getting the old B&S;engine running, as it isn't really worth it...

Gooserider

 

[pybyr]

Try a new spark plug, too-- I had an experience with an old (all cast-iron) Briggs engine where the spark plug was clean and would give a decent observable spark- and the engine was definitely getting fuel (I'd just re-done the carburetor), but I had no luck getting it to start.

In random desperation and rising frustration, I put in a new spark plug-- and it then started on the first pull and ran well.

A mechanic friend told me that spark plugs sometimes have flaws that aren't visible, and won't do anything you'd detect when looking at the spark when the plug is out of the engine-- but that they'll dud-out when faced with the engine's compression.

 

[quads]

but that they'll dud-out when faced with the engine's compression.

Very true. And sometimes when the engine was flooded bad, a new plug will foul, still show spark out of the engine, yet will not fire under compression.