boblohse Posted March 23, 2007 Share Posted March 23, 2007 I removed tappet cover,measured valve clearance .019 exhaust,.004intake.Not real experienced with small engines,learning as I go.Spec is .007-.009 for intake,I will either replace intake valve or file into spec.On a second note how critical is flywheel to crankshaft adjustment?This 23D has a key that bolts to flywheel,small engine manual is a little sketchy on procedure.I might just pull engine to bench so as not to be standing on my head for valve spring work and readjust flywheel.Seems like last small engine I had apart in high school in the 70's had a key in crankshaft that aligned with slot in flywheel.Learning as I go,does anyone have a simple flywheel adjustment procedure? Link to comment Share on other sites More sharing options...
MrSteele Posted March 23, 2007 Share Posted March 23, 2007 There is a key in the flywheel that will shear. It does not have to be completely sheared to make the engine out of time. Replaceing is as simple as removing the flywheel and replacing the key with a new one. You do need more clearance on your intake valve. While you have the cover and the head off, I would suggest lapping the valves for a tight seal when closed. Be certain to clean ALL of the lapping compound off before assembling the valves. Link to comment Share on other sites More sharing options...
MrSteele Posted March 23, 2007 Share Posted March 23, 2007 a Question for you.. this engine is recently rebuilt? And the valves are not right? I would never rebuild without taking care of the valves while the engine was apart. If you paid someone to do the rebuild, I'd stop payment on the check. Link to comment Share on other sites More sharing options...
boblohse Posted March 25, 2007 Author Share Posted March 25, 2007 quote:Originally posted by MrSteele There is a key in the flywheel that will shear. It does not have to be completely sheared to make the engine out of time. Replaceing is as simple as removing the flywheel and replacing the key with a new one. You do need more clearance on your intake valve. While you have the cover and the head off, I would suggest lapping the valves for a tight seal when closed. Be certain to clean ALL of the lapping compound off before assembling the valves. I have a taper fit flywheel with slightly adjustable key,I went through adjustment procedure in briggs manual,filed intake valve for .009 clearance reassembled and have a dry carb externally when fuel is turned on.While attempting to start engine carb dumps fuel out the bottom like pressure from engine combustion is pushing it back into carb-I took engine apart again front cover off timing marks seem to be aligned Link to comment Share on other sites More sharing options...
D-17_Dave Posted March 25, 2007 Share Posted March 25, 2007 Since you fixed the valve lash adjustment and pulled the cover to verify timeing on the crank/cam lets go back to the basics. The carb leaking a little gas is somewhat common on older carbs and there is plenty of discussion on carb service so I won't repeat it here, I'll let you look it up. The main question is since you've checked to flywheel timing do you have good spark? Link to comment Share on other sites More sharing options...
boblohse Posted March 25, 2007 Author Share Posted March 25, 2007 After reassembly I will see what I have-thank you Link to comment Share on other sites More sharing options...
MrSteele Posted March 26, 2007 Share Posted March 26, 2007 What you are describing sounds like the piston is in the wrong place; when the engine should be firing, the exhaust valve is open.While you are still in a torn down state, check the valve position at firing. The piston should be on top, with both valves closed. The exhaust valve should start to open on the next upward stroke. It almost sounds like you are 180 degrees out of time. Is there trash keeping the intake valve from closing? Also, check toi see if there are other marks on your cam gear. The mark you are using may not be a timing mark. The old ZZ I have, has no marks on the cam. Timing it was interesting. Link to comment Share on other sites More sharing options...
boblohse Posted March 26, 2007 Author Share Posted March 26, 2007 While remeasuring valve clearances I observed intake valve tappet rotating on upstroke and then sticking,so at position where greatest clearance should be when rotating flywheel one revolution there wasn't any.I had to pry on tappet rather forcefully to push it down.I disassembled engine completely cleaned and polished tappet stems,reassembled,checked clearances and freedom of movement is ok now.I am at a tight .010 clearance on intake valve stem to tappet..017 exhaust-when retiming flywheel, points and armature,compression stroke happens when points are closed.It seems to be a lot more noticeable than on previous assembly or maybe its just my perception is leaning in that direction,you are correct on intake valve problem thanks for taking time to think about it and responding.Incidently,I inspected that cam gear both sides tooth by tooth with a mag glass to verify marking to be accurate and the only one.Perhaps tomorrow there will be time to work on this jewel again. Link to comment Share on other sites More sharing options...
Recommended Posts