MM U backfires

55 50 Ron · May 20, 2023

What is the most likely cause of an MM U backfiring? Thanks for your help.

molinegb · May 20, 2023

Firing order wrong. Valve sticking or lastly timing. In other terms there is fire in hole when not supposed to be.

SWMolines · May 20, 2023

Water in the fuel can make a tractor seem to backfire.

T.R.K. · May 20, 2023

The 'fire in the hole when its not supposed to be' comment reminded me of the U with the 403 in it that ran for about 2 minutes and started backfiring. It had to have new valve seats as one eroded away because of rust on the seat. (The 403 had sat for a long time.) New valve seats and all was good to go.

MM U backfires

55 50 Ron

Well-known Member

molinegb

Well-known Member

SWMolines

Member

T.R.K.

Well-known Member

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