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OMC 70 hp

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 PostPosted: March 20th, 2014, 2:13 pm   
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Considering getting a 70 hp 56 cu in motor for my boat. Just wondering what years are more desirable and which years to stay away from. I will be looking for a long shaft motor and am also wondering if the newer years came with trim or not. The engine will be going on a 16' aluminum utility. The other alternative is an Evinrude Etec 60. I had a 50 Etec and know what I'm getting with them. Exceptional motor just do not like the price tag that comes with it. Any info would be appreciated.


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 PostPosted: March 20th, 2014, 3:00 pm   
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Pretty sure all the 56ci 70hp motors had PTT
Later years with the oval port had smaller carbs, likely better on fuel. I'd drop the VRO and premix though

Kevin

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 PostPosted: March 20th, 2014, 11:07 pm   
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1986-1989 1/2 56 pheads have the 4 spline crank, the later ones have the fine spline crank and will not work with Nitro drive shaft unless adapted po swapped out


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 PostPosted: March 27th, 2014, 10:27 pm   
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sheuninck wrote:
1986-1989 1/2 56 pheads have the 4 spline crank, the later ones have the fine spline crank and will not work with Nitro drive shaft unless adapted po swapped out


I keep.seeing people.dropping the vro I have never ever had a problem with a VRO...I have had quite a few omc motors and not once have I ever had an oiling oroblem with a VRO.
People have put this big stigma on the VRO yet I would personally love to see a motor that can be proven as a vro failure (oiling failure at that) yes they are stupid expe sove to replace but betweeny brother, myself and my dad and uncle..thats a LOT of omc motors since 84 amd nooje ever had a problem. Granted yes premixing is safest..I have even done it on a couole motors because of the bad name thw VRO got...until I read more and talked to a lit of omc technicians and the ones who took motors apart then they broke..never blamed the vro...just my 2cents...
56ci omc motors are pretty tough and will run on swamp.water and last forever..if they arent beaten gonna save a lot on fuel if you buy the etec...just depends how much you use it whether you rather oay a large amount in one shot or spaced out over a few yrs..


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 PostPosted: March 27th, 2014, 10:28 pm   
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Oops quoted wrong post haha


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 PostPosted: March 27th, 2014, 11:19 pm   
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79jcraft wrote:
sheuninck wrote:
1986-1989 1/2 56 pheads have the 4 spline crank, the later ones have the fine spline crank and will not work with Nitro drive shaft unless adapted po swapped out


I keep.seeing people.dropping the vro I have never ever had a problem with a VRO...I have had quite a few omc motors and not once have I ever had an oiling oroblem with a VRO.
People have put this big stigma on the VRO yet I would personally love to see a motor that can be proven as a vro failure (oiling failure at that) yes they are stupid expe sove to replace but betweeny brother, myself and my dad and uncle..thats a LOT of omc motors since 84 amd nooje ever had a problem. Granted yes premixing is safest..I have even done it on a couole motors because of the bad name thw VRO got...until I read more and talked to a lit of omc technicians and the ones who took motors apart then they broke..never blamed the vro...just my 2cents...
56ci omc motors are pretty tough and will run on swamp.water and last forever..if they arent beaten gonna save a lot on fuel if you buy the etec...just depends how much you use it whether you rather oay a large amount in one shot or spaced out over a few yrs..


they work fine on stock motors ;) its when you start spinning them up high and porting and adding high comp heads etc... then the vro fails. you just havent had a fast one yet :lol:

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 PostPosted: March 28th, 2014, 2:16 am   
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Even though it may work fine on a fishing motor I really don't want to trust something that's 20 or 30 years old and to mix my fuel for me.

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 PostPosted: March 28th, 2014, 2:59 pm   
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I agree Boomer..but it was a fishing boat or work boat he was talking about. I doscon ected ot on my gt150 cuz I ran it hard. They arent built to deliver the fuel needed at high rpm moreso than oil. They can deliver enough oil at high rpm. .its the fuel that is short.
Even 30 yrs old..if they are properly maintained, shouldnt be a problem. I have several new ones for 70hp omc motors. If you do want to run it with a new vro 2 pump just pm me if you get one and ill help you out. I have 15 to 20 functional pumps...they are onlynuseful to me if im foxing someknes motor and even then a good ised one is easy to find
.I have a brand new one with 5 gallons thru it. Guy bought it thinking the prob was bad pump. .but it was bad piston so I bought his blown motor


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 PostPosted: March 30th, 2014, 11:52 am   
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79jcraft wrote:
I agree Boomer..but it was a fishing boat or work boat he was talking about. I doscon ected ot on my gt150 cuz I ran it hard. They arent built to deliver the fuel needed at high rpm moreso than oil. They can deliver enough oil at high rpm. .its the fuel that is short.


:lol:

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 PostPosted: March 31st, 2014, 8:31 pm   
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Which years had the big carbs? Did they also change the reed blocks or decrease the stop distance for the reeds when they went to the small carbs?


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