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tohatsu 20hp 2010 four stroke HELP knocking at full throttle

S

sailfish1

New member
I have a 20hp New motor been running great but yesterday only at full throttle there was a loud pinging or knocking sound at the front of the motor. I did take everything out of the boat so it was much lighter than usual. Any suggestions would be great. Is it a spark plug? etc. or over reved? Thank you.
 
Isn't your motor still under warranty?
Check your oil level, first.
Depending on where the knock comes from. I've seen a couples and it's the valves that were not properly adjusted. This can be a manufacturer's defect, an improper break-in motor or was ran low/dried on oil once!
 
Verify crankcase oil level. Check the tach to make sure you are not "hitting the wall" of RPM. The staggered ignition of the ESG can make an unusual sound as the motor's RPM is limited. If all that checks out, have your dealer check it out under the 3-yr warranty. Might also be a valve lash adjustment. There is also a tech bulletin regarding crankcase bolt torque that applies to some serial numbers ending in "AA". Your 2010 motor is probably not in that group, but it's prudent to have it checked.
 
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