QuestionQUESTION: I have gone through the past Q and A and have not found “my problem” – I have a B & S 12 HP Model# 282707 Type 0122 01 – old as in 1995, but ran well until gear ring got chewed up and couldn’t turn the crankshaft enough to get started. So, I replaced the gear ring; flywheel and key was fine and put it back together. After some solenoid issues I was able to get the starter gear to engage when key was turned on but a “not good” sound, like stuck, required quick key turn off. I pushed the starter gear down to disengage from gear ring but the crankshaft (or flywheel) is now frozen or will not turn. I tried to turn the flywheel and also tried underneath via the stack pulley. Before I remove the flywheel again and see if the key is the issue (maybe due to insufficient torque?) I was hopeful you might be able to provide some guidance. I am hoping it is not the timing gear or crankshaft as it turned prior to this. I greatly appreciate any help you can offer, as 1-1/2 acres with very old push mower is no fun! Thank you very much!
ANSWER: Remove the spark plug and see if the starter will turn the engine. Often times the carb will leak causing gas to enter the crankcase, thinning the oil. The thin oil will cause the engine to hydro lock.
Your engine is pretty reliable but starter pinions wear out and battery go bad. Starter do go bad once in awhile but are pretty reliable.
Let me know if the starter will turn the engine with the spark plug removed.
Eric
---------- FOLLOW-UP ----------
QUESTION: Eric,
Thank you - I tried your suggestion of removing the plug and the starter gear engaged, although not fully with the ring gear but still the flywheel did not turn. I was unable to turn by hand either. Before first writing you, I had installed a new battery and there was definitely odor of gas in the dipstick previous to my first trying to start it up and I had changed the oil and new plug as well. Any other way to try to unlock hydro lock if that is the case? I'm grateful for your help. Thank you.
Lisa
ANSWER: If you can not turn the engine by hand with the spark plug removed then something is binding. It could be external or internal. I start by checking around the flywheel and output shaft to see if anything is causing the engine to bind. If you can see anything then start removing parts; mainly the flywheel. You should be able to visually see if anything is binding on the output shaft pulley. Make sure the belts or something else is not preventing the engine from rotating.
If you can't find anything external then it's time to start internal checking. Remove the head. Does the engine rotate? If not then something inside must be the problem. The only way to check the internal parts is to remove the engine and remove the oil sump/pan.
You well need a flywheel puller to remove the flywheel. If you have a method to take the mower to a shop you can have them remove the flywheel for a small fee and then you can continue to work on the mower using basic hand tools. You could also remove the engine with basic hand tools and then take to a local shop and have them remove the flywheel. Make sure you disconnect the battery and mark all the wires in addition to taking digital pictures so you know how it goes back together.
Let me know what you find.
Eric
---------- FOLLOW-UP ----------
QUESTION: Eric,
Yes, it's me again...thank you for all your help so far - When trying to remove the bolt on the flywheel I purposely didn't use a flywheel strap due to flywheel being locked up and finally the flywheel turned and it would turn about an inch and a half short of a full revolution going clockwise and the same in counter clockwise direction. I marked the flywheel and lined it up with a stationary mark which is how I came to the 1-1/2" short of a full revolution. Is there anything obvious that would cause that stop point? I'm assuming internal but will still check flywheel key if that is a possibility. Thanks for your help and patience.
Lisa
AnswerI have had loose connecting rod bolts cause this problem. However, I have also found flywheel magnets come loose and cause this problem as well. Now that I think about it, loose flywheel magnets found once, loose connecting rod bolts a couple of times.
Have you removed the head? I recall one engine, decades ago (early 90's), with so much carbon build up that the piston could not rotate a full revolution because the top of the piston kept hitting the carbon build up.
With the head removed you may be able to tell if a rod bolt is loose. Try rotating the engine until is stops rotating. Rotate the opposite direction a half revolution. Use a block of wood and tap the top of the piston to see if it moves. If the piston moves and the flywheel/crank doesn't move then this may be a sign of a loose rod bolt. You can also wiggle the flywheel back and fourth observe the piston. The piston should be instantly as you wiggle the flywheel indicating the rod bolts are tight.
Let me know what you find as it is very rare to find loose rod bolts in Briggs engines.
Eric
