hard 9re) starting briggs

[bgsengine]

Yeah, the fixed ones, pretty much are 25 to 30 degrees BTDC fixed timing you got to compromise between startability and performance at the designed engine speed.. back when they had points, we could "tweak" timing for special applications by simply adjusting the breaker point gaps.. when solid state ignition came into play, one had to remove or modify flywheel key to tweak timing.... nowadays with electronic modules, it is possible to program in variable timing (many high revving 2-strokes do that now) and probably the same with 4-strokes (Though Ive never paid attention other than Kohler's SAM modules, etc) to maximize engine emissions and performance as well as ability to start engine easily (timing closer to TDC for starting, pulling it further ahead of TDC as the RPM goes up..to match with engine's designed RPM)

[Skywatcher]

Greeting All

Speaking of tweaking the timing, this was when Tecumseh engines with the stepped flywheel key were common place on lawn mowers. If I was working on a unit belonging to a girl or an older person, I'd file about 1/32" off the wide side of the key and make sure I rotated the flywheel back against the key while installing to effectively retard the timing. This made the engine easier to start for those who couldn't pull the cord hard or fast, but didn't seem to affect the overall performance of the engine for average lawn mowing. This kind of modification would likely make a difference on an engine running a generator at 3,720 RPM, but a lawn mower engine running at 3,000 to 3,150 appeared to run quite happily. All the best,

Sky

[KE4AVB]

That is like using offset camshaft to cam gear keys in vehicle engines to change the engine performance. That was back we didn't have to fight the on board computers.

[38racing]

Wasn't the gap. Since the coil is easily replaced I'm going to try one from another engine. Only drawback is that the replacement is only known to work with an electric starter as there is no pull cord option on the donor.

[38racing]

Apparently not the coil. To restart I choked until a puff of fume out of carb intake. Next pull a bang out the muffler. Next pull it starts. I pulled the valve cover and checked valve clearance. Both ok. So next the flywheel key but before that just for the halibut I'm going to use the timing light and degree wheel to determine the timing. It will be interesting to see what it is if the key is sheared and what it will when fixed if that is the problem.

[38racing]

Does anyone know the position of the magnet relative to the legs of the coil when spark occurs assuming gap is correct.

[38racing]

So I used the timing light to mark flywheel and block for spark positive. Blower is at church and I forgot to take piston stop. Using a screwdriver free hand in cylinder isn't precise enough as in one setting I got timing 22 btdc and another at 30.

[38racing]

Well I located tdc with a piston stop and degree wheel. It's firing at 26 btdc which seem to be what it should be. I'm not sure whether there's any point in taking the flywheel nut off . always concerned about issues torquing that nut. I'm wondering if it's a carb issue. Maybe not pulling enough flow on hand cranking? This is one of those Nikki carbs. I had it off for cleaning to solve a noload surge.

[bgsengine]

sounds like a fuel or air issue to me .. given it is worse warm, I would wonder if it is not an air leak after the carb (gasket? crack? do a leakdown test for possible valve leaks?) or maybe winter vs summer blend fuel? or it could be just carb is on the lean side (or has some crud stuck somewhere that won't loosen when cleaning, and expands when it warms up..?)

[38racing]

sounds like a fuel or air issue to me .. given it is worse warm, I would wonder if it is not an air leak after the carb (gasket? crack? do a leakdown test for possible valve leaks?) or maybe winter vs summer blend fuel? or it could be just carb is on the lean side (or has some crud stuck somewhere that won't loosen when cleaning, and expands when it warms up..?)

I guess now would be a good time for leakdown test as I certainly can find TDC , lol. Just have to put my homemade gauge back together. I had borrowed part when I was testing the 2 cycle walbro carb .