Welcome aboard Bill.
What engine does it have?
Sounds like you've checked all the primary causes.
Certain engines have some certain failures that can be similar to yours.
Assuming it has overhead valves, and if it does, you might pull the valve covers and make sure the the valve train is working properly. Some models (Kohler CH and B&S's twins require valve adjustments at certain intervals and some are known to get enough play to where the pushrods either fall out or will not open the rockers enough for proper breathing.
Most times even a weak spark should atleast attempt to fire a cylinder. Another somewhat common occurance is the flywheel key can shear causing the engine to get out of time. You'll have to pull the flywheel inorder to see if that is the case.
Check the head bolts to make sure they are snug and if the engine has a fuel pump make sure it's providing fuel under pressure (sometimes it's just a squirt) to the carb.
Do those checks before you purchase anything else, especially a high $$$ item.
Let us knwo the engine model and we'll go from there.
Dave
What engine does it have?
Sounds like you've checked all the primary causes.
Certain engines have some certain failures that can be similar to yours.
Assuming it has overhead valves, and if it does, you might pull the valve covers and make sure the the valve train is working properly. Some models (Kohler CH and B&S's twins require valve adjustments at certain intervals and some are known to get enough play to where the pushrods either fall out or will not open the rockers enough for proper breathing.
Most times even a weak spark should atleast attempt to fire a cylinder. Another somewhat common occurance is the flywheel key can shear causing the engine to get out of time. You'll have to pull the flywheel inorder to see if that is the case.
Check the head bolts to make sure they are snug and if the engine has a fuel pump make sure it's providing fuel under pressure (sometimes it's just a squirt) to the carb.
Do those checks before you purchase anything else, especially a high $$$ item.
Let us knwo the engine model and we'll go from there.
Dave