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Hot!B&S engine, 23 HP, back fire through intake

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AVB
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Re: B&S engine, 23 HP, back fire through intake 2020/06/02 17:56:25 (permalink)
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RC62
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Re: B&S engine, 23 HP, back fire through intake 2020/06/03 08:24:47 (permalink)
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Thanks for the governor information, I'll have to check the static adjustment, didn't want to have to open the sump back up, hoping I have the initial placement governor lever inside the sump in the right location.
Coil air gap set to .010", found a setting range of .008 to .012, think this is correct.  Twin coils on this twin cylinder, is there a timing mechanism or does each coil fire with each rotation?  Rotation appears to be CW from the top of the engine.  Valve adjustment, two different theories, anyone have a preferred method?  1. After the intake valve opens and closes, rotating the engine CW, next time that piston is at the top, set both valves on that cylinder?  2. When any valve is fully compressed, open fully, set it's mating valve.  Intake fully open on cylinder 2, set the exhaust on 2, repeat for all valves?  I've set the valves 3 times using both methods and after a few rotations, the gap changes or I can't get back to the exact spot and the feeler gauge is usually tighter after a few rotations.  Using .005 to set the gap.  Books say .004 to .006, one shop I called said .002-.003 which I think is too tight.  Having lost a push rod and damaged the other, too loose is a problem but too tight may be a bigger problem?
AVB
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Re: B&S engine, 23 HP, back fire through intake 2020/06/03 12:47:09 (permalink)
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I look-up the engines that JD put the Z425 all came back with .004-.006 for in and ex valves.
 
Here is set at .004. As the .004 go in and the .005 doesn't I cam it set. You need feel around as the rocker arms go off tilt prevent the feeler gauge from going in sometimes throw the off the adjust that why must cyle the engine a few turns to check. Also must sure the rocker studs are not loose.
RC62
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Re: B&S engine, 23 HP, back fire through intake 2020/06/03 12:55:54 (permalink)
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AVB, do you know if this engine has a ACR cam shaft?  44L777 - 0115 B1 and 070917YG.  
AVB
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Re: B&S engine, 23 HP, back fire through intake 2020/06/03 14:49:02 (permalink)
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None of the images show an ACR mechanism but the camshaft could still be using a ramp grind ACR. Not sure it has the grind or not. I have only replace one these cams in ten years and that was because of badly worn lobe
RC62
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Re: B&S engine, 23 HP, back fire through intake 2020/06/03 15:07:08 (permalink)
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Thanks, so i'm going to ignore the ACR issue on this engine, 2007 model but internally this thing was super clean, still has hone marks in the lower cylinder walls.  Valve setting, Briggs online says move the piston 1/4" past TDC on the compression stroke, set both valves.  Agree?
AVB
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Re: B&S engine, 23 HP, back fire through intake 2020/06/03 15:33:46 (permalink)
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Doesn't hurt to follow the Briggs Procedure; although, I old school it here by have one fully depress and adjusting the other valve but that what I get for being 61 now. Hard habit to break beside I had to pull a couple heads as I broke my wooden dowel off in the cylinders so just went back to the old school method
RC62
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Re: B&S engine, 23 HP, back fire through intake 2020/06/03 17:03:18 (permalink)
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Not far behind, 58 here, always did one down, adjust the other on anything from large 16 cylinder Cats down to small (VW bug) engines but those seemed to set and stay put, this small thing with light springs is giving me a fit.
RC62
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Re: B&S engine, 23 HP, back fire through intake 2020/06/04 08:45:16 (permalink)
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Now what, got things back together, spinning with no plugs to lube and get the fuel flowing.  Plug in tried to start and experienced back pressure, starter stalling due to compression.  Remove the #2 cylinder plug, spun over fine, even started with out #2 plug.  Replace the plug and managed to start, sounds smooth, idles good might be a bit high, high speed sounds good, didn't engage the blades to verify the governor reaction but all looks like it's working.  Stop, attempted restart and compression issue, stalling the starter, apply full choke and again managed to start and run.  So compression release is an issue, does this mean the valves are too loose or too tight?  Plan to test by pulling #1 cylinder plug to see if I can confirm only one cylinder is causing the back pressure.
Advice?
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Re: B&S engine, 23 HP, back fire through intake 2020/06/14 13:41:10 (permalink)
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Hi RC
RC62
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Re: B&S engine, 23 HP, back fire through intake 2020/06/15 08:16:46 (permalink)
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sgtrudz
"Hi RC" ??
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