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1976 25HP Johnson making an odd noise

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Beebe

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I seized this motor up last year. Found a "new" power head online, and put it all back together. I rebuilt carb, rebuilt fuel pump, new plugs, new impeller, and set points. It starts pretty easy, but was spitting out of the fuel recirculation hose in a test tank. (barrel actually) I took it on the water, and adjusted the idle screw and the spitting has seemed to have gone away. It idles fine, runs fine slow, but every so often it makes a clunking noise, mostly at WOT. The odd thing is it does not loose power, it clunks, the motor shakes a bit and continues on. Is this a misfire? Any help would be appreciated. Thanks.
 
If that clunking actually feel like you're hitting a submerged object.... the lower unit is jumping out of and back into gear.
 
I don't understand the question.... If the engine acts like it's hitting something submerged, it's jumping out of and back into gear, that's it.

Either the shift cable is adjusted wrong, has too much play in it, or the clutch shifter dog and forward gear have worn shifter lobes which would require gearcase repairs.

(Centering Shift Cable)
(J. Reeves)

When all is as it should be, 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.

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.

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.
 
Well I did remove lower unit to do water pump, and it worked fine last year. I will try to adjust shift lever. Thanks
 
I suspect that when you re-connected the brass shift connector to the shift rod, you did not have the groove of the shift rod centered with the hole in that brass connector. If so, adjusting the shift cable or the actual shift lever will not correct the problem.
 
Did you properly adjust engine sync after doing all the work. It could be loading up due to improper engine sync? The throttle butterfly should just begin to open as the mark on the throttle cam passes center of the follower roller.
 
Re: 1976 25HP Johnson making an odd noise (SOLVED)

Thanks everyone! (Special thanks to joereeves) I reconnected the brass shift rod, and adjusted the shift handle. It was not going all the way in the handle indent. Also, in another thread joereeves suggested not to baby it when putting it into gear. So now I push it in to gear firmly. Thanks again.
 
You'r most welcome I assure you.

The fuel spitting out the fuel recirculating valve.... that's what it's supposed to do every time that piston's on its down stroke... BUT... it should be connected via a hose to whatever cylinder it's opposed to.
 
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