hard 9re) starting briggs

[38racing]

I bought a used briggs 20m114 (1350) snowblower engine to repower a blower. I'm at the point that it starts reasonably well from cold sit although it seems maybe choking isn't required but weather is still warm and prime may be enough. It runs great. Stays at rpm when auger engaged. Issue is restart. It seems that if I shut it off it is very difficult to restart. After a minute or 10 minutes. I can pull and pull. Choke, no choke, prime, no prime. No put put. then magically on a pull if fires right up. Run it a bit . problem repeats. Since originally it had noload surge I put carb through USC. That cleared the surge. I pulled the valve cover. Valves should be .004 to .006. They were at least .012. I adjusted both to .004. Same issue. the plug is a qc12yc and had been gapped to .020. Now at .030. I'm going to swap it out for a new ngk. My inline tester shows a good spark, almost too good. In the past I've noted that inline spark is very bright when straight to ground and less so when attached to plug. If plug doesn't solve it my plan is too pull shroud and check coil gap and the thought just came that maybe I better check the flywheel key. Any other thoughts?

[38racing]

Better after new plug.

[38racing]

I've just started using this blower. Still has an issue restarting by pull cord went hot. I can shut it off and with no choke or prime it will fire right up with electric start. With pull cord it doesn't fire. I found couple situations. If I prime it I reach a point where smoke come out the muffler but no fire up. If I quit priming it may start after several more pulls. Second situation is I apply one notch of choke. If nothing then another notch. Then I reach point that it single flames a backfire out the muffler. Then next pull with choke reopened and no prime it fires right up. Weird. Any thoughts?

[Arkie]

Agree with you, air gap and check flywheel key. Just little bit off key will cause such.
When checking ignition spark I like to use the Briggs 19368 and I can leave it inline while engine is running and check spark and also compare the run spark to when one don't start and when they are running. (watch the spark close in a shaded non bright area)

If that is 12v I would probably install a bat for long enough to get through winter so as not having to manual crank in cold weather.

Noticed that appears to be a Horiz shaft about 6-9 hp OHV.
I've had similar Briggs starting issues with other models.


One some if they started little easier for awhile after a new plug when hot I could throw a $12 clone magneto on some and they would go. The flooding seems to indicate either spark or timing or low compression..

Had a really strange one awhile back. (and a pleasant surprise) A Briggs twin 18hp L head with 12v starter was acting like yours and I had been all over the engine, another mag, checking valve lash, compression, leak down while hot, another carb and new plugs would help for little while but could put the removed plugs in another engine and they run ok and the aluminum flywheel starter rings went bad, couple teeth broke on the aluminum ring and was chewing up the starter bendix. I had a heavy duty bat on it so as I could eventually get it started. It was worse after I attempted a hot re-start 5 min or so after it was killed. I suspect this is the reason that I ended up with this give me engine, but I never look a gift horse in the mouth AT FIRST.
This was about 6 mo's ago I throwed another old flywheel on it that had a good starter ring and it now starts as soon as I hit the key hot or cold engine, starts so fast have to be ready to turn the key loose.???????????????????????(just stumbled onto that one) and it had a good flywheel key.??????

Them mag's have some electronics buried inside and some of the electronics are related to timing. I've found this out by trying to change just the electronic mag coils on some 2 cycle engines. Just because I see spark does not get me a run.

[KE4AVB]

Also make sure you got the correct plug installed.

PN 793541 (RC12PYC) (Champion 3071) for the EMS ignition system.

[38racing]

Ipl shows qc12yc which was in it. I replaced with ngk equivalent bk..... What's the difference between the leading q instead of r in the newer champion plugs.
Also coil comes up as 492341 and my after market shows this. I probably have an engine with that coil on it.
https://www.bantasaw.com/catalog/viewpr ... ?i=&p=4892

[bgsengine]

What's the difference between the leading q instead of r in the newer champion plugs.

"R" Type: Most resistor spark plugs feature a standard "R" type resistor. Most Champion "R" type resistor plugs are Champion SAC-9 suppressors. These extremely reliable resistors are formed from strontium carbonate, aluminum oxide and copper oxide powders. The resistance of a plug with SAC-9 suppressors are capable of combating typical RFI, but cannot be accurately measured with typical low voltage ohmmeters.

"FISS" Type: Fired in Suppressor Seal plugs feature a durable suppressor in the form of a proprietary glass mixture located inside the insulator. FISS plugs can be identified by their black terminal end. Technicians can check the resistance level with a conventional Ohmmeter, which should show a range of 3000-10000 ohms at room temperature.

"Q" Type: Uses a wire wound inductive coil (or electromagnetic suppression) to reduce RFI without negatively affecting ignition performance. "Q" type suppressor plugs are specified for most Evinrude and Johnson outboard engines with CDI.

"X" Type: Have a special resistor to meet more stringent RFI requirements.

from https://www.sparkplugs.com/what-are-the ... stor-types

[KE4AVB]

Plug type actually the depends the type and date codes of that 20m114 series.

[38racing]

I actually had to back out the carb mounting bolts to get the shroud off. To my eye the coil gap looked a bit excessive so I used a business card to reset. Will put it back together tomorrow.
Just out of curiousity I was watching some videos checking small engine time. One found it to be 26 BTDC and thought that was typical. As he anyone here ever measured the timing on any small engines?

[KE4AVB]

Excessive air gap can do it as lowers the induced voltage for one thing. But it will also put the initial timing closer to TDC or slightly afterwards.

As he anyone here ever measured the timing on any small engines?

IT can be done but it would take some ingenuity and the use of a variable timing light like the one I got here for vehicles. It just matter finding tdc and marking the flywheel a couple times and the crankcase once. Then using the variable timing light light ran the engine adjust the variable so TDC marks align up on the flywheel and the crankcase. From there you just read on the timing light the number degrees it took to align the marks.

But I have never actually checked the ignition timing of a small engine like the ones used on a push mower; never had a need to to do so.

Now checking a v-twin will be a little more involved as you need two set of timing marks and make sure coil you are checking as timing will 90 degrees or 270 degrees off depending how you look at the engine firing order between the two cylinders. But you could actually compare the timing between the two coils.