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Discussion Starter · #1 ·
Hi all, new to the forum and am getting started refurbishing a 1971 Bolens G8 (813) stamped frame. B&S 8hp runs well enough, but puffs a little blue on start and throttle up so thinking probably valve guides and possibly tired rings as well, but I'm just going to run it for now. Everything works now that I have redone the wiring and replaced a bad starter solenoid. Here's the before picture, and I hope to have it stripped down, all mechanicals gone through, and fresh paint by June. Looking forward to chatting with you.

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Welcome, lots of Bolens members on here to help ya.

Noel
 

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Welcome to GTT. Give the engine a tuneup, oil change and air cleanner change. Add Marvel Mystery Oil (MMO) to your gas. Using MMO in your engine will clean the combustion chamber, valves and rings. With a seasons use of MMO you should see a reduction of the smoking and an increase in compression. It has worked many times for me over the past 49 years. Good Luck, Rick
 

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I've got a G8 I'm working on in the background myself. But I know practically nothing on it. I can't get spark out of mine and I even changed the magneto... help?
 

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Discussion Starter · #10 ·
When I first got mine, with the B&S 8hp (model 191707), someone had mistakenly connected the magneto kill wire to the charging circuit (thus effectively grounding it). Once I got the wiring straightened out and ensured that wire was not grounded it ran fine. Magneto ignition is pretty simple - If the magnets in the flywheel are ok, and the spacing is set right, you should get good spark. I understand there is also a breaker point setup in those motors, so that might be a place to look as well.
 

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When I first got mine, with the B&S 8hp (model 191707), someone had mistakenly connected the magneto kill wire to the charging circuit (thus effectively grounding it). Once I got the wiring straightened out and ensured that wire was not grounded it ran fine. Magneto ignition is pretty simple - If the magnets in the flywheel are ok, and the spacing is set right, you should get good spark. I understand there is also a breaker point setup in those motors, so that might be a place to look as well.
Could you expand on "breaker point setup"? A fuse?
 

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Discussion Starter · #12 ·
The breaker point(s) are part of the ignition circuit. It's basically a switch that is normally closed, and then opened at a precise time by a cam lobe on the crankshaft. This sudden opening of the points is what creates the spark, by initiating a pulse of current through the ignition coil. The energy comes from the magneto, essentially a rotating magnet that passes by a pickup coil and induces a pulse of current. There is a capacitor (sometimes called a condenser) connected across the points to prevent arcing as the points open and close. It's not uncommon for points to wear so that they don't make good electrical contact, and for the points to get pitted due to arcing. They are not expensive or difficult to replace, and the set usually comes with a replacement condenser as well. Let me know if that info helps at all.

The magneto will have a "kill" wire that inhibits the ignition when it is grounded. This is usually connected to the key switch or a shorting bar on the throttle as a safety control. It has to be un-grounded for the magneto to function. Just as a caution, after a near miss with a live magneto on a Cessna 150, I don't trust the magneto "switches" to prevent the motor from starting when you've got your hands in there (rolling on belts etc). I always disconnect the spark plug wire as an extra precaution when turning the motor over by hand.
 
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