Motor now sounds different. Why?

[htuong95]

What does a miss firing sound like? I recently rebuilt my lower unit and gapped my spark plugs. I also took off the foam insulation from the motor cover.

Now it sounds different. I have not test it out on the water to see if it lost any power yet. It now sounds kind of like a Harley Davidson motorcycle. Sounds like "but-da-but-da-but-da" etc...

Could this because of the spark plugs or the removal of the insulation? I have a 1979 Johnson 35hp (2 cylinders, 1 carburetor). Thanks.

 

[jtexas]

Re: Motor now sounds different. Why?

well the foam insulation wasn't on there for appearances!

I've heard that the timing on harley's is purposefully set just a little bit off (forget which way), just to give 'em that sound.

 

[F_R]

Re: Motor now sounds different. Why?

Of course it sounds different. The foam was there to muffle the sound aka noise. The V Twin Harleys are way out of balance as far as the power strokes go. Sounds great, don't they?

 

[kai1414]

Re: Motor now sounds different. Why?

No... The timing on the Harley's isn't what accounts for the sound. Its the way the rods are indexed on the crank. They aren't opposite firing. They fire one right after another, just a short delay inbetween. This accounts for the Harely "vibration" that everyone loves and the unique sound. Honda tried something similar and Harley got all up in a bunch.... Honda no longer did it after that.

Sorry for the OT reply