TN-28 gas/oil ratio and spark plug gap

greenygreen

Seaman Apprentice
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May 13, 2014
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TN-28 ...i have read several contradicting threads on t series johnson gas/oil ratio and spark plug gaps and i was wondering if there was a general consensus on these..
 

jimmbo

Supreme Mariner
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May 24, 2004
Messages
13,442
Re: TN-28 gas/oil ratio and spark plug gap

I believe the ratio is 16:1 and the plugs 0.030"
 

greenygreen

Seaman Apprentice
Joined
May 13, 2014
Messages
48
Re: TN-28 gas/oil ratio and spark plug gap

thats what i run, just wondering about some saying run 50:1 or 32:1 in these old motors
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,442
Re: TN-28 gas/oil ratio and spark plug gap

thats what i run, just wondering about some saying run 50:1 or 32:1 in these old motors

If someone says to use anything less the 16:1, they are talking thru the top of their head. These old engines used friction bearings(bushings) and need lots of oil to act as a cushion and prevent metal to metal contact.
 
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