Motor knocking

[Henry Jr]

Snapper model 7800785 series 24 eleven years old
The motor knocks/bangs when I start it. Eventually calms down.
I must be missing some service operation?

 

[tom3]

First question, are you sure it's actually in the motor? Not in a drive or idler component?

 

[Scrubcadet10]

the engine isn't rocking when you start it is it? sometimes loose engine mounting screws/bolts will cause a knocking noise.

 

[ILENGINE]

the engine isn't rocking when you start it is it? sometimes loose engine mounting screws/bolts will cause a knocking noise.

Just to add to what Scrub said, Normally the knocking will be at start up and shutdown, and sometimes with sudden load changes like engaging the deck. but will appear smooth otherwise while running

 

[Henry Jr]

The knocking is definitely the motor and it is not loose.

 

[Fish]

You need to put up the engine's model numbers.

 

[Fish]

Put up a video of this also, if you can.

 

[Henry Jr]

Model 7800785, Series 24, bought new in 2011.
B&S motor model 210000 or 310000.
Have to check that.

 

[bertsmobile1]

One last check is to remove everything from the PTO and see if the knocking goes away.
While you are under there get some one to either rotate the engine by hand or crank the engine and check the PTO shaft for wobble
With the engine off see if you can push the crank shaft up, it needs around .010" to .030" free play but any more or any side play indicates a worn case ,
Once you are sure that it s inside the engine the prime culprit then the counter weight would be the most likely cause .

 

[Henry Jr]

Checking the above suggestions.
Will make a trip to the Dealer.