Lowering Compression on Johnson 135

Bunky1267

Cadet
Joined
Sep 20, 2009
Messages
12
I have an older Johnson and I hear talk of lowering the Compression on it by changing the heads with Johnson 115 Heads. Is this something I should think about ??
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: Lowering Compression on Johnson 135

Why? Are you in an underdeveloped country with crappy gas?
 

Bunky1267

Cadet
Joined
Sep 20, 2009
Messages
12
Re: Lowering Compression on Johnson 135

No here in the US maybe they were wanting to run lower octane fuel ??
 

wilde1j

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Apr 15, 2002
Messages
5,964
Re: Lowering Compression on Johnson 135

Just run 87 octane and don't worry about it. Your heads are fine.
 

kenmyfam

Supreme Mariner
Joined
Aug 10, 2006
Messages
14,392
Re: Lowering Compression on Johnson 135

I certainly would not consider doing anything like that especially if there is no real reason for it. I have heard of some folk putting 2 head gaskets on to achieve the same thing but still don't really know why !!!
 

Bayou Native

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Joined
Aug 30, 2009
Messages
12
Re: Lowering Compression on Johnson 135

I'd trade you my 115 heads for yours, I'm looking for more compression.
 
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