"Clunk" at Higher Speeds

[Sport Lido]

Hope you guys can help me diagnose this problem...I have a 1976 35 HP Evinrude outboard on a 14' boat. While running at higher speeds, every so often you'll hear a loud "clunk" which you can feel and hear throughout the boat. Kind of like missing a gear or something and then will run just fine for another 30 seconds or so and then another "clunk"". Can anyboby point me in the right direction??

 

[daselbee]

Re: "Clunk" at Higher Speeds

Yup.
Many threads on here about that same issue.

In your lower unit, there is a part assembly called the clutch dog. It physically meshes with machined notches in the forward gear hub area. If the clutch dog jumps a cog while underway, you will get that shuddering clunk, like you hit something.

You might be able to adjust the shift rod to help it, but it probably needs service. Look at the oil for metal.

Good luck...this is a big deal if you have to get it fixed.

 

[Sport Lido]

Re: "Clunk" at Higher Speeds

Thanks for the reply Daselbee. I checked the oil and it looks brand new with no signs of metal. I assume the shift rod adjustment is up near the motor.....right? Should I be turning it in or out??

 

[daselbee]

Re: "Clunk" at Higher Speeds

Too old for me to say absolutely. BUT, if it is like most all of them, you take the LU off, and turn the shift rod in or out to attain the correct height. Then put the lower back on. I just looked at the parts breakdown, and it looks like it is adjusted the way most all of them are.

It would make sense if someone had the LU off, to do the water pump, and re-assembled. If your problem started right after that, then someone turned the shift rod, or didn't double check height.

If it just kinda started doing it, more and more frequently, then it is probably clutch dog wear from use and age.

 

[Sport Lido]

Re: "Clunk" at Higher Speeds

daselbee....thanks for the help!