1450 Spark Knock (14hp)?

[FLETCH14519]

Good morning everyone. Here recently I started up the Ol cub cadet after 6 months. After allowing it to warm up and start doing yard work, I noticed at mid to high idle what sounds like a spark knock? I left the throttle at half way or lower for the rest of the time using it. Also have a little bit of a “smoke puff” coming out of the exhaust. Is it time to rebuild the engine or is it something else I could look into? I haven’t drove it since. It was my grandfathers tractor before he passed. So I’m trying to keep it going. If there is any other info you need let me know. Thanks again and Happy easter

[cooperino]

Originally Posted by FLETCH14519

Good morning everyone. Here recently I started up the Ol cub cadet after 6 months. After allowing it to warm up and start doing yard work, I noticed at mid to high idle what sounds like a spark knock? I left the throttle at half way or lower for the rest of the time using it. Also have a little bit of a “smoke puff” coming out of the exhaust. Is it time to rebuild the engine or is it something else I could look into? I haven’t drove it since. It was my grandfathers tractor before he passed. So I’m trying to keep it going. If there is any other info you need let me know. Thanks again and Happy easter

Hello.
"spark Knock" is typically something that happens in engines that utilize EGR, timing advance, etc. However, Old fuel can mimic that type of sound. Also, If your engine is running too rich "kohlers like to run on the rich side" carbon buildup could also mimic that condition. If you have not done so already, I would suggest a complete fuel system cleaning. Tank, lines, carb and filters. Then I would try to adjust fuel mixture. Lean in out until its smooth then turn towards rich just a smidge.

[FLETCH14519]

Originally Posted by cooperino

Hello.
"spark Knock" is typically something that happens in engines that utilize EGR, timing advance, etc. However, Old fuel can mimic that type of sound. Also, If your engine is running too rich "kohlers like to run on the rich side" carbon buildup could also mimic that condition. If you have not done so already, I would suggest a complete fuel system cleaning. Tank, lines, carb and filters. Then I would try to adjust fuel mixture. Lean in out until its smooth then turn towards rich just a smidge.

Awesome I will give this try and see what happens

[FLETCH14519]

After trying a few things above, my tractor is still making the rattle/ spark knock noise :-/


I found a link to what my cub sounds like. Fast Foraward to the 5:34 to 5:37 Mark, when he puts his tractor in high throttle, you can hear that rattle/ knock noise. This is what my tractor sounds like from mid to high throttle.

https://youtu.be/0mXvzeiMKTw

Any help would be awesome....jus want to get to the bottom of this.

[cooperino]

Really need to see a video of your machine running.

[FLETCH14519]

Originally Posted by cooperino

Really need to see a video of your machine running.

I will get one this afternoon and download it to the thread.

[FLETCH14519]

Here is the video of the rattling / knock noise I am talking about. Once I raise the throttle is when it picks up. Link is below

https://youtu.be/3_VSWQ4WeVI

[ol'George]

Sounds like either an internal problem like a worn rod or the iso mounts are gone and it is hammering on the oil pan.
At about 6.5 to 1 compression ratio you don't have "spark knock".

[cooperino]

Originally Posted by ol'George

Sounds like either an internal problem like a worn rod or the iso mounts are gone and it is hammering on the oil pan.
At about 6.5 to 1 compression ratio you don't have "spark knock".

Have to agree with George on this... Both counts. Another question. Does it do this from cold start? Does it get worse after warm up?

[mortten]

My engine doesn’t move near that much I’d check the mounts.