Rebuilt Evinrude 115 - Rattle during deceleration

[trendsetter240]

Just took my newly rebuilt E115ELEDR out for the break in today and I notice a rattle sound when the engine is decelerating. It's smooth and sounds great during acceleration and cruise but when you pull back hard on the throttle there is a distinct rattle sound as it slows. The rattle stops when the boat has slowed.


Here's the video Evinrude 115 1996 v4 - rattle on deceleration - YouTube . The rattle can be heard at around 55 seconds.

Any thoughts?

 

[bob johnson]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

i have always had that on my motor...i nwas told it is normal......sounds like a bad knock!! clanking like crazy on deceleration

bob

 

[boobie]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

Sorry I can't listen to your video 'cause my sound is out. What you described sounds like a decel knock which is normal on some mtrs in the right conditions.

 

[trendsetter240]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

Thanks guys, I think I figured out what the loud rattling was. This morning I went to start the motor and the starter would just spin and not contact the flywheel. So I pulled the cowlings off and found this. Pretty sure this was what was rattling around.

The retaining clip came off the drive gear. I replaced it today and will test the boat tomorrow. Hopefully the knock is gone.

 

[boobie]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

Let us know if that was it. I never seen that before.

 

[trendsetter240]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

Let us know if that was it. I never seen that before.

I'll update for sure. I remember thinking the clip was loose when I put it in but thought it would hold. I guess I know better now!

 

[bob johnson]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

what a pain to check that are on those style motors..... you have to mark all the linkage settings, before you take all that stuff off the top of the flywheel.... but you should still have that decel noise.....I have been running mine for 4 years now and get it when I decel suddenly from speed

bob

 

[trendsetter240]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

Ran it again today and the rattle is still there though much quieter. I also changed my prop to a larger pitch so that may have also had an effect.

I'm going to assume this is normal and keep my eye on it.

Cheers

 

[jim j geezer]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

I'm theorizing here, perhaps over my head, but I've experienced the same characteristic on several 2-cycle outboards.

It's the throttle butterflies. Picture 'em at WOT speed. They're pretty much locked in place. The throttle advance mechanics are pushing it/them open so far they're jammed against the butterfly stop block that's cast in as part of the carb body. When you suddenly retard the throttle, that 'jamming' force goes away leaving only air inflow through the venturi to press that butterfly back against that stop block.
Two entities become engaged in a battle: (1) the ever reducing velocity of the air coming into the venturi, -vs- (2) the fixed value, hair fine spring that attempts to hold the butterfly closed against incoming air through the venturi at low speed.

 

[multimech]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

I'm betting you are hearing the reeds rattling when deecelerating. Normal.

Although the starter problem is not.

 

[jim j geezer]

Re: Rebuilt Evinrude 115 - Rattle during deceleration

When the engine runs the reeds slap - regardless of RPMs. Also, being contained by their keepers, the 'clap travel' distance is precisely fixed between closed and wide-open-against-the-stop.

Compare a "golf clap" where your hands barely move to create a quietish/delicate/polite audible acknowledgement for performance, -vs- a 5-year-old kid's arms-spread-wide, enthusiastic attempt to create a LOUD racket.

I'll stand by my butterfly theory.