115 Connecting Rod Query

[stephennicholls531]

Here?s a question I haven?t see asked on the forum. I?m in the process of rebuilding/restoring a 115 HP V4 Evinrude, and the (all the same part number) connecting rods that came out of this motor were 4 completely different styles and very different weights (many tens of grams different), and which now fit nicely in the garbage can. I now have a set of 4 rods of all the same part number and style, and am able to match the weights so that I can make two pairs of rods that weigh exactly the same as each other. Here?s the query: Would it be better practice to put the matched rod sets on the 1 / 2 and 3 / 4 piston positions or should the matched rod sets go on the 1 / 3 and 2 / 4 pistons? I?m looking to reduce rotational vibration as much as is possible and practical. Any thoughts?

 

[tashasdaddy]

Re: 115 Connecting Rod Query

what year and model# there are alot of 115's.

 

[stephennicholls531]

Re: 115 Connecting Rod Query

This was originally a 1993 115 Model TLETS, but since then, there have been a lot of people playing around with this puppy. Some time back, I did figure out that the powerhead had been exchanged with a 1986 90HP one, and that the original ignition system had been swapped out for a system from about 1980. But in any case, the query about the connecting rods is a generic one, applicable to all Evinrude V4s from 1978 to 1995. Hope that this helps.

 

[Dhadley]

Re: 115 Connecting Rod Query

Actually all the rods in all 115's are the same from 1974 on. Crossflow and 60* loopers. Basically, if it's not a 1973 115 all the rods are basically the "same".

As for the rods there are several different molds / castings and probably more than a couple vendors that make them. On the rods themselves you'll see white dots, blue, yellow, green, orange and probably some other colors I forgot. And rods with no dots. And rods that have been machined on the side of the caps, found mostly in Sea Drive motors.

Then there are rods of different lengths. Some have beams that are almost polished, or at least have way less of a casting line than others.

The bottom line is that all the different weights, lengths and configurations are within a given manufacturers spec. You can mix & match but at stock (6000) rpm you'll never see the difference.

You might see a smoother idle if you balance the entire rotating assembly including the flywheel. But those pistons are so heavy I doubt that will make any noticable difference.

It really won't matter where you put the rods, just enjoy the process as well as the end result.

 

[stephennicholls531]

Re: 115 Connecting Rod Query

That's exactly what I was looking for - and thanks. This particular rebuild process has been - so far - very enjoyable, and I can't wait to get this one back out onto West Coast waters and hook into a nice Chinook (King) salmon. Thanks again.

 

[noelm]

Re: 115 Connecting Rod Query

it can be a tad disapointing and nerve wracking when you dismantle something and find that it has been tinkered with before and you are not exactly sure if all is as it should be!! but take dhadley's advice, I guess there is not too many more knowledgable on these than him! and he is spot on this time as well.