So i'm one of many who had an issue with 75mm TB, you know bad idle, and such. So for the past 2.5 month, my Mac TB just sat ont he garage, and i was just happened to looking at it(infact, i was playing with it, by blowing in to it and crop. lol)
then i noticed there was considerable amount of air leak. So i taped up Idle air hole with tape, and tested again. And again, there is alot of air going through. so i got looking around, and come to realise that there are considerable amount of leak from 2 bolts that secure TB brade to the shaft. I mean i was just blowing, but when engine is running, there is quite bit of vacume created behind the blade, and surely enough to suck sufficient air through the leak. If enough air is passing through there, that would surely cause bad idle(high idle), right? so i sealed up the area(see pic) with some paint(didn't know that to use), and i'm going to try it again. lets hope this cures the age old Mac TB issue huh?
View attachment 500967
View attachment 500969
then i noticed there was considerable amount of air leak. So i taped up Idle air hole with tape, and tested again. And again, there is alot of air going through. so i got looking around, and come to realise that there are considerable amount of leak from 2 bolts that secure TB brade to the shaft. I mean i was just blowing, but when engine is running, there is quite bit of vacume created behind the blade, and surely enough to suck sufficient air through the leak. If enough air is passing through there, that would surely cause bad idle(high idle), right? so i sealed up the area(see pic) with some paint(didn't know that to use), and i'm going to try it again. lets hope this cures the age old Mac TB issue huh?
View attachment 500967
View attachment 500969