Thread: Strange knock from motor
03-10-2009, 04:35 PM #1
Strange knock from motor
I just did my first start up of the brand new motor I built myself. Everything turned over with no problem before I dropped it in. It started on first try with no problems and revs up with no problem. The only thing is when I let go of the throttle and the motor revs down there is a knock on the way down, but the knock is too slow to be something hitting. I think my 01 Sea Doo XP does the same thing but I canít remember exactly. It has a -.03 milled head but I used 93 Oct fuel premixed with oil. Anyone have any ideas?
03-10-2009, 06:24 PM #2
- Join Date
- May 2008
same for me it's appears to be normal with this motor
03-10-2009, 06:39 PM #3
Good, now I feel much better anyone else have this same occurrence?
03-11-2009, 10:01 AM #4
Is it a KNOCK or is it a kack kack kack. Sounds silly when I type that. Anyway when I went higher compression and free flow it began cackling on decel. Ever been to the drag strip and heard an alcohol engine cackle? Similar sound. I think you're fine.
03-11-2009, 11:04 AM #5
03-11-2009, 12:37 PM #6
Piston "slap" is not normal. That would indicate excessive clearances.
03-11-2009, 12:44 PM #7
sorry fullboogie. thought these were aftermarket pistons like weisco.
03-11-2009, 01:08 PM #8
Oh, no apologies needed. Didn't mean to be rude - I think we're talking about the same thing but just calling it something different.
03-11-2009, 01:14 PM #9
mine makes a knocking noise when i turn it off. i dont know where it comes from. but my ski hasn't blown up yet...knock on wood
03-11-2009, 03:47 PM #10
I had Millennium Tech match the pistons to the cylinders so there would be no way that it could be piston slap. It is more like a Bang.........Bang. not a dink,dink,dink.
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