Murray Problems
#1
07-05-05, 03:59 PM
Murray Problems
I had the 17.5 hp Murray rider that wouldn't start. You gave me some good advice about turning the flywheel with a wrench and checking to see if the belt was maybe keeping it from turning. There was a lot of rust on th pulley and the belt was stuck to it. The flywheel and starter turn and turn and turn, but it still won't start. I did replace the spark plug. And I do smell gas. And once or twice it sort of backfired. It smokes. Before I got the advice here, the techs at a shop used by WalMart told me to tighten the overhead valves. As a last resort I tried this. How do you know how much to tighten them? Cheese did say I might try adjusting them( to .005") But where do you measure? The lower rocker is on the spring, but it is not perfectly centered and this troubles me. I wish I had never opened the OHV cover. I think it would have started if the flywheel had been free to turn.
#2
07-05-05, 05:14 PM
terryrschneider,
Cheese is correct. Don't worry about the rocker arm not being centered. It will work it's way to center when pushed by the push rod. You need to use a set of feeler gauges. These can be purchased at your local wal-mart or parts store for under 10 bucks. The feelers are made of thin sheets of metal in different thicknesses. The thickness of each sheet is labeled on the sheets themselves. Add these sheets together until you reach (.005). This will most likely be only two of them, (.002) +(.003). These two sheets will = (.005).
You will need to rotate your crank shaft until you reach top dead center. This will be the compression stroke. Both valves closed and piston at the very top of it's travel. By wiggling the feeler gauge, insert it between the rocker arm and the end of the valve stem. You will need to adjust the nut or shaft, which ever you have until you feel a draging resistance on the feeler gauge. Do this for both valves.
Afterwords, rotate the crank through two full rotations until you reach Top dead center again. Re-check the rockarm clearenece, and readjust as previous.
Re-tighten any jam nuts, rotate two full turns and check again. Readjust if needed. This will put the clearence where it should be.
TIPPPPS: Do all the above with the spark plug removed and while slowly turning the carnk shaft. You can feel the top of the piston by using a screw drive placed through the spark plug hole.
God Bless
Dave 237
Cheese is correct. Don't worry about the rocker arm not being centered. It will work it's way to center when pushed by the push rod. You need to use a set of feeler gauges. These can be purchased at your local wal-mart or parts store for under 10 bucks. The feelers are made of thin sheets of metal in different thicknesses. The thickness of each sheet is labeled on the sheets themselves. Add these sheets together until you reach (.005). This will most likely be only two of them, (.002) +(.003). These two sheets will = (.005).
You will need to rotate your crank shaft until you reach top dead center. This will be the compression stroke. Both valves closed and piston at the very top of it's travel. By wiggling the feeler gauge, insert it between the rocker arm and the end of the valve stem. You will need to adjust the nut or shaft, which ever you have until you feel a draging resistance on the feeler gauge. Do this for both valves.
Afterwords, rotate the crank through two full rotations until you reach Top dead center again. Re-check the rockarm clearenece, and readjust as previous.
Re-tighten any jam nuts, rotate two full turns and check again. Readjust if needed. This will put the clearence where it should be.
TIPPPPS: Do all the above with the spark plug removed and while slowly turning the carnk shaft. You can feel the top of the piston by using a screw drive placed through the spark plug hole.
God Bless
Dave 237
#4
07-14-05, 05:06 PM
terryrschneider,
Make sure to remove your spark plug for safty. Remove the top cover over the fly wheel. This cover is held on by three to four screws or bolts around the sides. After removing this cover you can then rotate the crank shaft with your hand by slowly turning the flywheel clockwise. With the valve cover removed and a screaw driver held lightly in the spark plug hole you can feel the piston movement and see when both valves are closed.
God Bless.
Dave237
Make sure to remove your spark plug for safty. Remove the top cover over the fly wheel. This cover is held on by three to four screws or bolts around the sides. After removing this cover you can then rotate the crank shaft with your hand by slowly turning the flywheel clockwise. With the valve cover removed and a screaw driver held lightly in the spark plug hole you can feel the piston movement and see when both valves are closed.
God Bless.
Dave237
