See the wee square thing ontop of the motor, rip it off, And put on a flow restrictor, then it'll work fine, just DON'T change oil flow direction rapidly =snap shaft or chain
wee square thing lets the oil avoid the motor in tough going (its meant to prevent breaks in sudden change in oil flow)
My deeres driving the nc brush would not lift arms while driving (I had flow restricted on tractor spools) but when i done as said above with inline flow restrictor worked fine, as motor can only cope with 60litre a min oil flow max i think from memory
Stephen you'll wonder how you managed before without it!!!