Twin 1.6 omc restoration

Raffus

Cadet
Joined
Mar 25, 2011
Messages
9
I bought a 25 ft sea devil with twin 1.6 omc. One motor has rebuilt bubbleback with five hours on it the other had bad powerhead. So I bought a 78 evinrude 115 just for the powerhead, compression is good 115 all the way around. Used my carbs intake ignition flywheel. The only problem I had was the shift throttle cables. So I made a bracket used two precast threaded holes and mounted to block. Works fine. I was under the impression that 78 to I think 88 was the block I needed to do this. The more I read the only difference is the mounting point for the shifter/thorttle cables, is this true.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Twin 1.6 omc restoration

That 78 is a flatback engine, without the bubble back. Usually the machined factory port timing is somewhat different between the flatback engines and the bubble back (higher performance) models. Possible that there is a difference in the carb throat size also. They should both be the same cubic inches, at 99.6. The 78 has a different shifter mechanism under the bottom carb. The heads are different, these 78's ran strong compression compared to the 86 and later. The 78 carbs have choke plates instead of the fuel primer system.
 
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