1997 Yamaha 225 Lower Unit Knocking in drive

[brett8388]

Hello and thanks in advance for any advice you may have. <br /><br />Yesterday I replaced the water pump in my Yamaha and today when I checked the motor on the hose I noticed a knock in the lower unit. It only knocks in drive and isn't a constant thing, but I'm concerned. There is a little play in the prop - in and out, not side to side. It may have been knocking for a month or two, but I haven't noticed it until this morning. Here are my questions:<br /><br />Could I have botched the waterpump job so badly that I messed up something in the lower unit? The pump is working fine now, but I had some trouble getting the old one out and pounded on the shaft holding it a bit.<br /><br />Do you think my lower unit is about to sieze up?<br /><br />Should I run it the way it is, or take it in for service?<br /><br />Lastly, anyone know a good mechanic in the Houston area?<br /><br />Thanks again,<br /><br />Brett

 

[rodbolt]

Re: 1997 Yamaha 225 Lower Unit Knocking in drive

hello<br /> not knowing which motor you have cause ya did not post a model number I will give general answers. in 97 the 225 was made in a 3.1 and a 2.6 L version. both used a different ign.<br /> the one that normally chatters when shifted into gear with the prop out of the water is the 3.1 however the 2.6 will do it to a lesser degree. the ign design of the 3.1 is such that it drops a cylinder and sometimes two depending on engine RPM and shift switch positions. what your hearing is the slack being taken up and then released and taken up again on the shifter clutch. sounds like its gonna die. why did ya beat on anything? you do it your selfers sure are a squirrly lot. mmmm let me see emerycloth to polish the shaft $1.20. replaceing bearings after they have been pounded on 1500 or so. I can buy a lot of emery cloth. <br /> the other source of gearcase noise in all V yamaha's since 1995 is the collar and retainer on top of the water pump is not installed or installed incorectly. contrary to back yard beliefs it does not lock the impeller in place. it actually keeps the drive shaft from bouncing up and down and making chattering noises as the slack comes out of the drive shaft torrington bearing.there again the 3.1 L is more prone to make noise if it was not installed properly. its rare that I see a DIY'r install one right but lets hope ya did. if its a 3.1 you will notice its not the smoothest idleing outboard ever built. try it with the prop in the water and the noise should go away. the power output on the crankshaft of the 3.1 is not equal for all 6 cyl at an idle plus it uses a harmonic balancer. if the balancer becomes loose it will sound like a rod knock . at first <br /> so odds are you have nothing wrong. good to keep an ear out for any changes in the sounds of the motor

 

[John from Madison CT]

Re: 1997 Yamaha 225 Lower Unit Knocking in drive

Rodbolt: <br /><br /> My '97 250hp Ox66 doesn't have the gearcase collar and retainer installed near the water pump. As a result, my lower unit "knocks" at low RPM's.<br /><br /> Is there anything bad about this? Will is cause damage?<br /><br />John

 

[rodbolt]

Re: 1997 Yamaha 225 Lower Unit Knocking in drive

yes and possibly<br /> why is it not installed? the parts are about 7 dollars and take about 30 seconds to correctly install when doing the water pump. if its missing you will need 2 spacers one wave washer the collar and the retainer, it requires removal of the pump housing to install

 

[brett8388]

Re: 1997 Yamaha 225 Lower Unit Knocking in drive

Thanks for the help. I have a freshwater (bass fishing) 225 - I believe that's the 2.6 L. I had the waterpump "professionally" replaced last time and the washer and collar described in the above post weren't there. I'll buy some today.<br /><br />If I install the washer and spacers, should the noise go away?<br /><br />The "beating" I put on the shaft was lightly with a brass hammer - I hope I didn't damage anything.<br /><br />Brett

 

[rodbolt]

Re: 1997 Yamaha 225 Lower Unit Knocking in drive

most likly not. but its possible to damage the impeller. next time someting does not fit try a light cleaning and polishing. the collar assy goes on top of the water pump impeller. unless someone has installed a pre-95 gearcase. a quick way totell is to post the model number. or count how many bolts screw into the gearcase. if its 7 its a 2.6 if its 8 its a 3.1. do not count the fastener that holds the trim tab on.you will need the 2 spacers the wave washer the collar and the retainer. side a spacer,wave washer,spacer ,nylon retainer then the collar. pull up on the shaft while tapping the collar in place. the aft prop spacer works well for this.slide it down the shaft,pull up on the shaft and tap the collar down. then install the pump housing. if you have a pre-95 gear case the shaft will not have an undercut just above the water pump. if its undercut or original it should have it. if you forget the pull up on the shaft step it renders it all useless.