land rover 90 1985 swb 2.25 petrol troubles

hi i have recently benn given my gramps 90,1985 2.25 petrol.im trying to bring it back to its former glory but im having promblems with it ticking over?now the weather has turned cold its started to play up, it starts up first time but does not tick over now,i have recently changed oil and sparkplugs,air filter.the exhaust downpipe near the engine is blowing and needs a new gastket would that effect it?i dont no much about land rover engines slowly learning but could do with some help here please.
thanks benn