difference between a 1983 90 and 115

[demon1]

I just got a 90 johnson that needs a little work for free . I have a 115 evinrude and another for parts . they both look the same but what is the difference? and also what is the electrical box on the back of the 90 hp engine for ? mine does not have it

 

[Haffiman]

Re: difference between a 1983 90 and 115

The box at the box is probably the trim relays.
Go to boats.net and check the parts list to find exact which parts are different.

 

[bktheking]

Re: difference between a 1983 90 and 115

I have an 83 johnson 90, no electrical box under the cowl, 2 powerpacks is all. If it's mounted to the transom like Haffiman said it's trim goodness. It could however be newer than an 83 and what you are seeing at the back under the flywheel is the regulator/rectifier.

 

[Chinewalker]

Re: difference between a 1983 90 and 115

The major difference between the 90 and 115 is the carburetors (bigger on 115) and intake & exhaust porting (bigger on 115). Pretty much everything else is the same.

The black box, if mounted on the exhaust cover, is probably the trim relay box - used on trim units utilizing a 2-wire trim motor. The older transom mounted boxes were typically for the 3-wire trim motors. It's possible your 90 didn't originally have trim and someone added a 2-wire system from a later motor (bolts right up). After almost 30 years, any measure of mixing and matching could have gone on...

 

[emdsapmgr]

Re: difference between a 1983 90 and 115

The factory started mounting the trim boxes on the outer exhaust cover starting with the 1984 models. You can check the aluminum casting plug on the top of the block-it may have the model number stamped there, indicating the year.

 

[demon1]

Re: difference between a 1983 90 and 115

it might be newer . cool ,thanks for the info. can I put on the 115 carbs on the 90 or would this be a mistake

 

[Haffiman]

Re: difference between a 1983 90 and 115

You may, but only if you at the same time 'square' of the intake ports behind the by-pass covers.
This however brings you into fine tuning with possible jet changing and requires some real knowledge.
You run the risk of loosing at the bottom, but gain at the higher RPM's.
Just trying to 'tune up' a 30 year old engine without first tearing it apart for a close examination is not what I would recommend.

 

[emdsapmgr]

Re: difference between a 1983 90 and 115

You should be able to run the 115 carbs on the 90. Give it a try. You may find the 115 carbs may overfuel somewhat at top end-you may need to jet it down a little.