Grinding noise when put in gear

[D42ON]

I just bought this boat and I don't know the history of it. When I got it I couldn't get it to start so I gave it a complete tuneup and some new batteries and it fired right up. When I put it in gear it makes a grinding noise then goes away. It does it in reverse to but only when you put it in gear. It sounds like something is loose but the prob is tight. I was wondering if it's low on gear oil would it make that sound. I'm looking on my outdrive and I can find a drain plug or a vent. I see a plug on the top but I think thats to fill it. It's a 1970 Slickcraft with a mercruiser straight 6 160. Any help or suggestion would be greatly appreciated. Thanks.........

 

[Barnacle_Bill]

Re: Grinding noise when put in gear

Change the oil in the lower unit, If its milky colored you have a bad seal or gasket on the drain or vent plug. Whe you change the oil pump it in at the lower plug where it drains out. When it starts coming out the vent plug install the vent plug. The remove the pump and install the drain plug. When putting it into gear, PUT it in gear. Don't just ease it in as the gears are not syncronized like on a car.

 

[Don S]

Re: Grinding noise when put in gear

Moving to Mercruiser, Volvo and OMC I/O or Inboard Engine Problems forum.

 

[Haut Medoc]

Re: Grinding noise when put in gear

Welcome to iboats......
Are you putting it firmly into gear in one fluid motion?.....
Ya should not shift gingerly......​

 

[D42ON]

Re: Grinding noise when put in gear

I was going slow when putting it into gear. I been using the water muzzles I never had it in the water yet.

I have a 1966 Starcraft 120 4 cyl mecruiser also and on the outdrive the drain plug was near the bottom unit and I know the outdrive I got now will be different but I can't find the drain plug on it. Where abouts should I look? I see a plug on top and thats it. I want to drain it and put some new gear lube in it.


I know this doesn't go in this thread but since I"m here I'll ask. I had to replace the trim unit on my boat. The new one works great but on the controller it says UP in/out Down. The in/out brings it up and the down takes it down but the up button does nothing. I don't know if the controller is bad but it seems like I don't need to use the UP button because it already goes up and down. Is this right?

 

[ziggy]

Re: Grinding noise when put in gear

isn't there a drain plug on the ft. of the very bottom of the drive. just above the fin.....port side..... the plug at the top is a vent only, not for filling. you fill from the bottom till it leaks out the vent, then it's full.

sounds like someone did some wireing on yer trim. probably on purpose i'd think. up+ in/out together is for trailering. in/out only is for trim only. if in/out brings it all the way up. someone modified how it's hooked up. probably because the limit switch on the drive breaks and is nla + impossible to get at to service w/o much tear down.... just use as is, and don't over trim up while underway......

yep, don't shift gingerly, shift crisply........

ya sound like ya need a service manual......try this. the oem service manual on line.....big files. but it's worth it.... yers is service manual #1

http://www-alt.mercurymarine.com/mnetdata/sisdata/srvcovr.pdf

 

[D42ON]

Re: Grinding noise when put in gear

Thanks for all your responses. You guys have been a big help thanks.

 

[Haut Medoc]

Re: Grinding noise when put in gear

Thanks for all your responses. You guys have been a big help thanks.

Make sure you replace the seals on the fill & vent screws when you change the gear lube.....

 

[fishdog4449]

Re: Grinding noise when put in gear

I just bought this boat and I don't know the history of it. When I got it I couldn't get it to start so I gave it a complete tuneup and some new batteries and it fired right up. When I put it in gear it makes a grinding noise then goes away. It does it in reverse to but only when you put it in gear. It sounds like something is loose but the prob is tight. I was wondering if it's low on gear oil would it make that sound. I'm looking on my outdrive and I can find a drain plug or a vent. I see a plug on the top but I think thats to fill it. It's a 1970 Slickcraft with a mercruiser straight 6 160. Any help or suggestion would be greatly appreciated. Thanks.........

try re-adjusting your shifter cable, maybe it is not going all the way into gear
if the clutchdog is worn it may make that noise too

 

[fishdog4449]

Re: Grinding noise when put in gear

Welcome to iboats......
Are you putting it firmly into gear in one fluid motion?.....
Ya should not shift gingerly......​

exactly. you should almost slam it into gear, it sounds rough but its better for the engine
the engine should make a "clunk" noise when going into gear, if its a rattling or grinding you are either shifting too slow or somethings wrong

 

[D42ON]

Re: Grinding noise when put in gear

OK I'm back Again. I found the drain plug on the lower unit. When I took the plug out the first thing to come out was water and not gear lube and then the gear lubed followed. I have two plugs at the top on each side in the same place. Which one is the vent or are they both vents? I have the pump tool and gear lube allready to go I just need to know which vent plug to look at when I"m filling to see it coming out so I can stop pumping the gear lube. Thanks......

 

[Haut Medoc]

Re: Grinding noise when put in gear

Not good......
There should be zero water in there.....
You need to pressure test your drive, locate the leak & make the necessary repairs.......
The vent plug should be top port......​

 

[D42ON]

Re: Grinding noise when put in gear

I took three plugs off the outdrive and all of them were missing the o-ring. I'm hoping that that is why there was water in it.

 

[ziggy]

Re: Grinding noise when put in gear

I took three plugs off the outdrive and all of them were missing the o-ring. I'm hoping that that is why there was water in it.

don't know about 3 plugs. but anyways, be sure the seal washer aint still on the drive. mine seem like they are always stuck on the drive and i gots to pry them out........yer notion that they'd be the cause of the water seems like a good first assumtion.
the pressure test hm is talking about is the way to go though. then ya know it ain't got a leak somewhere's...............

 

[D42ON]

Re: Grinding noise when put in gear

Are the o-rings round and rubber or are they flat like a gasket? What do I need to get to pressure test it or do I have to go and have it done somewhere?

 

[ziggy]

Re: Grinding noise when put in gear

"http://www.mercstuff.com/page13.htm"

or ya can make one from a lub pump + yer own gage + yer bicycle pump.

the seals that i've had are blue, flatish, fiberish, feeling seals and they get stuck on the drive side when ya remove the vent/fill screws. though their easy to get out, just look for them to be sure the old one aint still there........