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11hp briggs & stratton timing


im replacing the connecting rod. got timing marks lined up right . it just pops and shoots gas from...

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  #1  
Old 09-17-2008, 10:20 PM
peggyfran1 peggyfran1 is offline
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Angry 11hp briggs & stratton timing

im replacing the connecting rod. got timing marks lined up right . it just pops and shoots gas from carb .what did i do wrong HELP
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Old 09-17-2008, 10:26 PM
bstrucker bstrucker is offline
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Default Re: 11hp briggs & stratton timing

That's a tough one without some more info,what's the model?Usually back firing through the carb means very early timing or a valve hanging up.Make sure the valves are working and seating ok.You say the timing marks are lined up right,is there a possibility your flywheel key is partially sheared or that the flywheel is located wrong?
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Old 09-18-2008, 08:11 AM
K D Redd K D Redd is offline
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Default Re: 11hp briggs & stratton timing

Check valve clearance. If aluminum block valve clearances are .005 to .007 inches on the intake and .009 to .011 on the exhaust. I set them at .007 and .011 after a rebuild. If you had the valves and seats ground when you replaced your rod you need toset the valves. You hae to remove the valves from the engine, remove the springs from the valve spring chamber and use a feeler gauge to check clearance. If you need to increase the clearance you must gtind the end of the valve.
Also check for a sheared flywheel key. I have at time not gotten the flywheel tight enough and the first hit of the engine would shear the key. On older point system you would lose fire on the newer Magnetron ignition system it will change the ignitions timing causing all kinds of problems.

Kent
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Old 09-18-2008, 12:51 PM
peggyfran1 peggyfran1 is offline
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Unhappy Re: 11hp briggs & stratton timing

i only replaced the rod con. ididnt do anything with the valves .i guess i will have to remove the valves. am i right? this is my first time at this. thanks frank
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Old 09-18-2008, 02:26 PM
peggyfran1 peggyfran1 is offline
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Default Re: 11hp briggs & stratton timing

Quote:
Originally Posted by K D Redd View Post
Check valve clearance. If aluminum block valve clearances are .005 to .007 inches on the intake and .009 to .011 on the exhaust. I set them at .007 and .011 after a rebuild. If you had the valves and seats ground when you replaced your rod you need toset the valves. You hae to remove the valves from the engine, remove the springs from the valve spring chamber and use a feeler gauge to check clearance. If you need to increase the clearance you must gtind the end of the valve.
Also check for a sheared flywheel key. I have at time not gotten the flywheel tight enough and the first hit of the engine would shear the key. On older point system you would lose fire on the newer Magnetron ignition system it will change the ignitions timing causing all kinds of problems.

Kent
if i only changed the connecting rod and didnt do anything with the valves would i still need to reseat the valves.
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Old 09-18-2008, 03:11 PM
bstrucker bstrucker is offline
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Default Re: 11hp briggs & stratton timing

It never hurts to reseat the valves when you have the head off,most times it's not necessary but in this case,with the trouble your having trying to start your engine,it may help.
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Old 09-18-2008, 06:30 PM
peggyfran1 peggyfran1 is offline
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Default Re: 11hp briggs & stratton timing

where should the valves be with the piston tdc.with the timeing marks lined up the piston is about 1/4 way down. ive tried several different way with the piston tdc. its getting to be a real pain. frank
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Old 09-18-2008, 08:54 PM
bstrucker bstrucker is offline
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Default Re: 11hp briggs & stratton timing

At TDC on the compression stroke,both valves should be closed,you can tell if they are by trying to turn them,if they turn easy,they aren't on the seat.If your not on the compression stroke,both valves will be just off the seat.The way to tell if your on the compression stroke is by turning the engine over in a clockwise rotation,compression will be just after the intake valve closes.I still don't know what model your working on here but all B&S engines that have worked on have a dimple on the crankshaft counterbalance that you line up with the dimple on the camgear,I'm not really sure where the piston is but I think it is part way down the cylinder when they line up.
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Old 09-18-2008, 11:02 PM
peggyfran1 peggyfran1 is offline
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Default Re: 11hp briggs & stratton timing

im sorry the model is 28c707.i tried lineing up the two marks you are refering to earlier but it wouldnt start just sputter. ill try getting piston up then turn cam so both valves are closed. ive been trying to do it with exhaust closing and intake starting to open. i sure appreciate your help and patience. frank
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