Popular Post chuckholes Posted yesterday at 12:54 AM Popular Post Share Posted yesterday at 12:54 AM Had been sitting 24 years in one spot. Ran when parked lol Any pointers on trying to start it? It’s a 1981. Are they 24 volt negative ground? 4 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/ Share on other sites More sharing options...
Brocky Posted yesterday at 01:05 AM Share Posted yesterday at 01:05 AM Where are you located?? That looks like a GA plate on it????? First try to roll the engine over with a bar on the front pulley bolt. If free, start from there. Quote Brocky Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563123 Share on other sites More sharing options...
chuckholes Posted yesterday at 01:07 AM Author Share Posted yesterday at 01:07 AM 1 minute ago, Brocky said: Where are you located?? That looks like a GA plate on it????? First try to roll the engine over with a bar on the front pulley bolt. If free, start from there. I’m in Warner Robins Ga. Found the truck in Bullock County Ga Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563124 Share on other sites More sharing options...
mowerman Posted yesterday at 01:09 AM Share Posted yesterday at 01:09 AM make sure you remove all the injectors and shoot a bunch of mystery oil into the cylinders and let it sit a week or so before you try to turn it over also remove inlet turbo oil line and shoot oil into turbo bearing,,,and make sure the turbo spins free nice going bud,,,,,bob 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563126 Share on other sites More sharing options...
Brocky Posted yesterday at 01:12 AM Share Posted yesterday at 01:12 AM 2 minutes ago, chuckholes said: I’m in Warner Robins Ga. Found the truck in Bullock County Ga Please add it to you profile.. Being a F-712 what engine does it have in it??? If it is a 2 stroke Detroit you have to make sure the rack is free or it will run away!!!! 1 Quote Brocky Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563127 Share on other sites More sharing options...
chuckholes Posted yesterday at 01:19 AM Author Share Posted yesterday at 01:19 AM 6 minutes ago, Brocky said: Please add it to you profile.. Being a F-712 what engine does it have in it??? If it is a 2 stroke Detroit you have to make sure the rack is free or it will run away!!!! Believe it’s a Mack motor with a 5speed. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563128 Share on other sites More sharing options...
tjc transport Posted yesterday at 01:28 AM Share Posted yesterday at 01:28 AM if it is an 81, it should ne negative ground. as for 12 or 24 volt, you would have to look at the alternator and starter to be sure. or it could throw a monkey wrench in the plans and be 12 volt electrical and 24 volt starter. 1 Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563132 Share on other sites More sharing options...
chuckholes Posted yesterday at 01:46 AM Author Share Posted yesterday at 01:46 AM Odd thing is it currently has 4 22.5 inch wheels and 2 20 inch wheels . One side or the rear duals is mismatched. Front has one 22.5 and one 20 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563133 Share on other sites More sharing options...
Brocky Posted yesterday at 03:27 AM Share Posted yesterday at 03:27 AM (edited) 2 hours ago, chuckholes said: Believe it’s a Mack motor with a 5speed. I do NOT know all of Mack's numbering system, BUT in the R models a 600 series had a Mack engine and the 700 series had outside vendors engines.. The 22.5 is the tubeless version of the 10-20 tube type tire. Size wise they are interchangeable. Just start looking for decent 22.5 rims and tires and you will be in good shape. Depending on what you are going to use it for, as a hobby truck you can get away with what you have is they are not too far worn or out of date.. Edited yesterday at 03:31 AM by Brocky Quote Brocky Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563136 Share on other sites More sharing options...
BOBWhite Posted yesterday at 04:15 AM Share Posted yesterday at 04:15 AM Glad you got it out of there! A few more years with those pine needles and there would have been nothing left of that truck. Your brake and throttle pedal might be stuck so I would spray some stuff on those asap. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563138 Share on other sites More sharing options...
chuckholes Posted yesterday at 04:47 AM Author Share Posted yesterday at 04:47 AM 30 minutes ago, BOBWhite said: Glad you got it out of there! A few more years with those pine needles and there would have been nothing left of that truck. Your brake and throttle pedal might be stuck so I would spray some stuff on those asap. The cab is fairly decent. Are you familiar with the truck? Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563140 Share on other sites More sharing options...
terry Posted yesterday at 07:33 AM Share Posted yesterday at 07:33 AM 4 hours ago, Brocky said: I do NOT know all of Mack's numbering system, BUT in the R models a 600 series had a Mack engine and the 700 series had outside vendors engines.. The 22.5 is the tubeless version of the 10-20 tube type tire. Size wise they are interchangeable. Just start looking for decent 22.5 rims and tires and you will be in good shape. Depending on what you are going to use it for, as a hobby truck you can get away with what you have is they are not too far worn or out of date.. The R700 series had the longer hood for cat or cummins engines, but i also seen them with mack six cylinder, and mack V8 engines. Terry 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563142 Share on other sites More sharing options...
cruiseliner64 Posted 19 hours ago Share Posted 19 hours ago Thats a beautiful truck.best of luck with it.keep us posted as you get things done. Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563150 Share on other sites More sharing options...
BOBWhite Posted 15 hours ago Share Posted 15 hours ago 11 hours ago, chuckholes said: The cab is fairly decent. Are you familiar with the truck? No not this perticular truck. I'm just remembering all that was wrong with our Mh cabover after sitting a few years outside. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563168 Share on other sites More sharing options...
Mark T Posted 7 hours ago Share Posted 7 hours ago We're gonna need a picture from behind the cab looking forward ( in under the cab ) put this engine mystery to rest 😏 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74817-finally-brought-my-f712-home/#findComment-563211 Share on other sites More sharing options...
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