Very subtle knock when I turn the prop by hand

koolerb

Petty Officer 1st Class
Joined
Oct 22, 2005
Messages
370
1992 three cylinder 60 hp Johnson. I've got about three hours on it this year. I just noticed that when I spin the prop by hand I get a very subtle knock, or tap coming from the midsection or lower unit. I'm going to drain the gearcase tomorrow just to take a look at the fluid.<br /><br />Any ideas?
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: Very subtle knock when I turn the prop by hand

That's usually caused by a shift cable being slightly out of adjustment.... unless someong has had the lower unit off and has the shift rod measurement off specifications. However, check the cable adjustment as follows.<br /><br />The proper method to adjust the shift cable is to disconnect the cable from the engine. Move the shift linkage on the engine to find the center of the play in neutral, and when found, leave it centered.<br /><br />Now, grab the end of the shift cable sleeve, push and pull it to find the center of the play there, and center that play.<br /><br />Adjust the trunion on the threaded portion of the shift cable so that the centered play of the cable lines up with the centered play of the engine's shift linkage. Install and lock the shift cable with the retaining clamp in that position. That's it.
 

HOU-CHAP

Seaman Apprentice
Joined
Nov 21, 2004
Messages
34
Re: Very subtle knock when I turn the prop by hand

I am by no means an expert, but it sounds like your gearcase may be barely in gear. I had the same thing happen to me one day when I spun my prop by hand. Had never noticed it before, and no telling how long it had been doing it. Does your prop spin when on the muffs and out of gear? I adjusted my shift cable out until the little tap/knock when away when spun by hand. Hopefully someone will come in and give you a dead on answer, but that's my .02 anyways
 

HOU-CHAP

Seaman Apprentice
Joined
Nov 21, 2004
Messages
34
Re: Very subtle knock when I turn the prop by hand

I must type too slow.. :) <br />That's spot on what I did to mine...
 

koolerb

Petty Officer 1st Class
Joined
Oct 22, 2005
Messages
370
Re: Very subtle knock when I turn the prop by hand

Good answers! I was thinking the worst. I'm going to check the adjustment ASAP.<br /><br />Thanks
 

koolerb

Petty Officer 1st Class
Joined
Oct 22, 2005
Messages
370
Re: Very subtle knock when I turn the prop by hand

The point at which the tap seems to go away isn’t at the center of play in the shift lever; its as some pressure is applied towards reverse. I did have the lower unit off, and the powerhead. <br /><br />I guess the shift rod need to be adjusted a turn or two down. <br /><br />Can this be done without unbolting the powerhead?<br /><br />When I hooked up the shift rod I had the powerhead unbolted so I could get my hands in there a little easier and it was still almost impossible.
 

koolerb

Petty Officer 1st Class
Joined
Oct 22, 2005
Messages
370
Re: Very subtle knock when I turn the prop by hand

Also, I noticed that from center at the shift lever; there is a lot more travel into gear aft into reverse, than into gear forward.<br /><br />Does it sound like the shift rod needs to be adjusted?<br /><br />I don't want to unbolt that thing if I don't have to. It's in a tough spot.
 
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