1974 vs. 1985 Johnson 115 swap option

S

spg76013

Recruit
Joined
Jun 4, 2012
Messages
1
Hi -
I bought a bass boat with a 1985 115VRO + outboard unit (with tilt/trim) and the engine was blown (ate a piston and cracked a cylinder). Rather than rebuild that motor, I just bought a working 1974 115 HP + outboard unit (with *OUT* tilt/trim) for $300.

Question 1: can I swap the 1974 powerhead onto the 1985 unit?

If not, I'll be putting the 1974 engine/outboard unit onto the boat.

If I do that, then: Question #2: can I somehow utilize the 1985 tilt/trim mechanism onto the 1974 unit?

If not, I guess I'll just set the tilt to a nominal cruise angle and live with that, right?

I'm a newbie, this my first boat. Any advice greatly appreciated.

Thanks,

Sean Gillen
Arlington, Tx
 
B

bullcity101

Seaman
Joined
Mar 30, 2012
Messages
73
Re: 1974 vs. 1985 Johnson 115 swap option

If you google it, marineengines.com or something of the nature you will probably be able to answer your own questions, but with my very limited knowledge and zero research my first instinck is no to both your questions. Welcome to the boating world! It has been a whrilwind ride for me. I bought an old homemade skiff with a non-working engine and got so tired of it I traded for a much older running engine. Best thing I have ever done. Now I get to enjoy the water. If it were me I would put the 74 on it and trim it manually. I think in the future you could get a CMC (if thats what it's called, jackplate...) for it and be a happy camper.
 
jimmbo

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,964
Re: 1974 vs. 1985 Johnson 115 swap option

I can't answer the first one, but I know you will not be able to use the newer trim system on the older motor.



Welcome to iboats
 
E

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1974 vs. 1985 Johnson 115 swap option

The powerhead won't swap. The powerhead bases are different. The powerheads changed in 1978 when they changed to the dual thermostats. The midsection exhaust adapters are different. The newer tilt and trim won't adapt to the 74 transom bracket system. OMC did make an early power trim system in 1974. That old style trim system has been NLA for many years, but you may be able to scrounge up a good used one on a junk motor. It should bolt right on to your 74. If you find one, make sure you get the electronic parts (solenoid and wiring harness) that are required to make it function.
 
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