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slb04786

Brigg's 16 HP timing

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slb04786
Hey Guys, First of all, Happy Birthday Simpletractors. Second, I'm rebuilding the 16 HP Briggs with Magnetron ignition, in my 7116. Got it timed according to the service manual (I thought)and tried starting it and it is backfiring and shearing flywheel keys. I tried adjusting the timing by moving the mounting plate for flywheel module. Still couldn't get it to run right. Taking a second look at the service manual I noticed that the 320000 series had different timing marks to align the crank and cam gears. So I removed the engine and disassembled and retimed the crank/cam gears and the syncro balancer gears. The difference in the cam/crank was only one tooth. My question is would the crank/cam timing being off one tooth make that big a difference in the running and backfiring. I know it might not run smooth but this wouldn't even start. I only ask because I want to make sure there isn't something else to look at before I reinstall the engine. Sorry for the long post. Any ideas are appreciated. Stan

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roma3112
one thing you want to be sure of is the torque of the flywheel not. It is crucial, i rebuilt my cast iron 12hp (300421) and had the same problem that you are describing. i took that engine off and appart several times checking the timing of the cam/balancers ect. It rurned out to be the flywheel nut, i think on this engine it is over 100ftlbs!!! So if you think you got the timing right on dont go crazy check that nut and get it to spec before you secondguess yourself like i did. good luck john

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slb04786
Salthart, The engine number is 326437 type 0169. Why would the magnetic need to be reversed just from dissassemly and reassembly? I didn't convert from points/condenser or change anything in the ignition system. I hope I don't have to send it away. My son is anciuos to use it and I'm more than happy to let him snowblow in the cold if he wants to. Stan

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slb04786
Salthart, No problem. Did the same thing reading the service manual. Those things cover so many models, you need to be careful. I set the timing for cast iron blocks the first time. In trying to diagnose my problem I turned the page and there is another page for the 320000 series cast iron which time differently. Would have been nice if the technical writers had said cast iron blocks except 320000 series on the previous page.

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slb04786
Ambler, That is what I thought. However some of the cast blocks time differently than the others. I don't have the service manual at work and I won't be home until late this evening. The manual shows that you line up a dot on cam gear with a line on the crank gear but if you look at the next page it shows that the 320000 series engines use a line on the crank near the front counter weight. You have to put a chalk mark on the front of the tooth of the crank gear that lines up with this mark and then line the crayon mark and the dot up. Like I said it is only one tooth difference but I'm hoping this will solve the backfiring, kickback, and key shearing I'm seeing with the engine. Stan

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Salthart
I really don't think your cam timing would or could cause kick-back. you will get a weak run and maybe even some backfire if bad enough. But the piston is hooked to the crank and there are only 2 ways I can think of to get kick back.. Carbon in the combustion chamber hot enough to pre-ignite and bad ignition timing... Are you sure you got the cupped washer in place under the flywheel nut ? And how sure are you that you got the flywheel nut torqued to the right specs ?

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ambler
Stan We actually have 320400 type. The bearing pressed on my crank is opposite the cam and crank gear and the second bearing is in the bearing support. If you look at fig 21 section 10 page 8, bearing is in the way of crank gear mark. I'm setting cam and crank shafts in second engine right now. If I recall magneto needs to be place correctly, look at bottom of page 7 and top of page 8 section 2. I'm off to the garage but I'll check in later. Running a phone line in there in warmer weather.

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slb04786
Ambler, In response to your PM.... No I haven't had a chance to put the motor back in and test it. Probably Sunday. I see what your were talking about in the service manual for timing with the bearing installed. The mark on the crankshaft throw will line it up with the crankshaft gear mark. So I was timed right there. I'm not sure where my problem is now. The engine will kick back on the starter hard and backfire throught the carb. I have already tried it throghout the different timing settings by moving the Magnetron module in it's slots. I'm thinking maybe the intake valve is not seating properly and allowing gas to burn in the intake behind the valve. Will have to check that out I guess. Any ideas are appreciated. I'll copy and post this in my thread too.

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maxtorman1234
slb04786 , I am having a very similar problem with my kohler k341(16hp), and it backfires and wont run properly. I have checked the valves, points, ignition coil, condenser, under the shroud, head gasket, timing, and still nothing. Spoke to a guy who has workd on these small engines for 15 years and says he thinks it is something to do with the ignition. Still gotta put my engine back in and try it, hope this may help.

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