View Full Version : reverse knocking
steplift20
05-07-2006, 10:39 PM
took my boat out today and ran great except when i put it in reverse the motor would bang sometimes like it was slipping in and out of gear
anyone know what that could be
I have a 1988 150 mercury o.b it never did that before
is a loud bangging noise
msbhammer
05-07-2006, 11:59 PM
I have a Merc. 200 Black Max.
Let me know what you find out.
reelapeelin
05-08-2006, 08:48 AM
Better have it looked at soon...sounds like one of those things that could cause more damage if not fixed ...could be a bad ''clutch-dog''... ::)...
phester
05-08-2006, 09:45 AM
that happened to a Mercury I had, the forward and reverse gears were fine but on the back of each gear are the clutch dogs, and in forward, just a bit over idle speed it sounded and felt like I was driving the boat over a bunch of rocks....not a good feeling. Step20, I hope it's the case, but , if it is, you already need a lower unit [ the reverse gear, that is]
Airslot
05-08-2006, 10:03 AM
I've got the same 88' merc 150. Drain your lower unit lube and look for metal particles / chunks. The bottom screw is magnetic so you may have some gunk stuck to it. When my lower went bad, I caught it before it "blew", that gear lube looked like it had glitter in it.
Good luck,
Airslot
Stinky_Hooker
05-08-2006, 10:08 AM
It is possible the linkage is off and its not going FULLY into reverse?? They will knock in that situation.
Remember, think simple..FIRST. ;D
phester
05-08-2006, 10:13 AM
your right Stinkman, I would check the lower unit oil like Airslot said, then look at the linkages and cable adjustment for the reverse....hopefully the damage has not already been done
macojoe
05-08-2006, 11:06 AM
yep oil then linkage
phester
05-08-2006, 11:29 AM
that happened to a Mercury I had, the forward and reverse gears were fine but on the back of each gear are the clutch dogs, and in forward, just a bit over idle speed it sounded and felt like I was driving the boat over a bunch of rocks....not a good feeling. Step20, I hope it's the case, but , if it is, you already need a lower unit [ the reverse gear, that is]
ooops, sorry Step, I meant to say " I hope it's NOT the case"....good luck
steplift20
05-08-2006, 01:04 PM
how do you check the lincage
because i clean the motor this year[should have left it dirty] and it seemed hard going in reverse and then the banging
so i thought mabe i have to put grease somewhere but where
Airslot
05-08-2006, 01:22 PM
Hmmmm.....Hard shifting....maybe you've got a cable bound up. To check, pull the cowling off the motor and find where the shift cable hooks to the linkage. Remove the cable from the linkage. Now, try shifting from the helm and see how much effort is needed.
Now, for the more important part, operate the linkage by hand on the motor. Shift into both reverse and forward. When in gear the prop should spin about a half a revolution and then lock up.
If your lucky something is out of adjustment or you need a new cable.
Let us know,
Airslot
steplift20
05-08-2006, 08:51 PM
phester no problem i knew what you meant
steplift20
05-08-2006, 08:54 PM
i took off the cowl and greased all the points that neede to be greased, i started the motor with the ears on and put her in reverse and there was no knocking but it might only do it under a load
I dont know i want to put it in the lake by my house and try it before i go out again but the water is low in the lake so ill have to figure out something else
phester
05-08-2006, 10:26 PM
you definitely have to check it while you're under way. Do what Airslot said...drop it in gear, grab the prop w/ two hands and try to turn it..[make sure the key is off or pull your spark plug wires.......unlikely, but you don't want to start the motor by accident, then you'll have a REAL problem] if you can crank the prop around w/ "medium" effort it's probably the clutch dogs, Did you check the lower unit oil??? That should be step # 1. Keep us posted
steplift20
05-09-2006, 09:10 PM
i didnt check the lower unit oil yet but i will let you know how it turns out
steplift20
05-09-2006, 11:11 PM
i just put the engine in revese gear and turned the prop gut it only turns one way and makes a clicking sound
when i put the gear in forward it turns the other way and makes the same clicking sound
i thuink its good not the dog[am i right]
willy
05-09-2006, 11:28 PM
That sounds normal, if you have a big garbage can or similar you can fill with water and put a light load on and operate the the gear shift from the motor you might find like has been said that you are not getting a full engagement with the controls from the helm.
macojoe
05-10-2006, 12:12 AM
I like using my foot ::)
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