I have Maurray 42536x92a twin engine with 42" Cut with 17 hp B&S twin II,. It truns one with Choke on... but as soon as I puch choke down... it turns off the mower... what can be the issue... also is it safe to run mower all the time with choke on at full... please help... what can I do to fix it... it was working fine yesterday... Please help