Noise when changing gear - Just change gear oil

[kvan64]

Hi, I just bought my boat with a 2006 Yamaha 2 stroke. I just change the gear oil (as per instructions from the user manual). I noticed that the magnetic screw on the bottom has some very fine dark metal dust attached to it. I didn't pay attention to the noise before but after changing the gear oil and run a water hose with the muffs, after 5 mins running I put it in gear and heard noise (stronger than a rattling - maybe a bit like a grinding sound). It made the same noise for the reverse gear as well. Could anyone clarify my concern. Thank you for your time. DK

 

[Yamajoe]

Re: Noise when changing gear - Just change gear oil

When you dropped the oil what colour was it? Fine metal shavings is normal, what you dont want to see are crumb size and larger bits of metal. What Hp is your motor?

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

Thanks for the reply, the color was from pale yellow to grey/brown (a bit dark near the bottom - came out first). The motor is 40HP - 2006 model. I am worried about the grinding noise. but it just happens once when put to gear then stops. Is this normal or not? Or is it because I did not operate it properly?

 

[Yamajoe]

Re: Noise when changing gear - Just change gear oil

The lower unit (LU) noise you describe is not normal. The pale coloring indicates water has penetrated the unit, either through the two plug screw gaskets, or seals. If noise persists, then you need to get this looked at. Always use new gaskets on those 2 screws. Just checking, did you fill oil from the bottom plug until it ran out of the top plug.

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

Only the upper screw gasket was broken but I replaced both gaskets. I pumped the oil through the bottom hole until it spilled out from the top hole. Did everything as per instructions from the manual. I was just sliding to gear (R and F) and came the noise and also left quickly. So it looks like I need to have it looked at by a Yamaha dealer. Do you think that it gonna cost me a lot? I thought that I made a good buy of this boat

 

[Yamajoe]

Re: Noise when changing gear - Just change gear oil

So, is the noise constant, or does it end soon after you are in fward or rverse? What is your idle RPM?

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

It only happens when I put to gear (F & R) and stops straight away. I didn't look at the Gauge for idle RPM. It's a bit dark now (in Australia) so I will look at it tomorrow. What idle RPM is correct?

 

[rodbolt]

Re: Noise when changing gear - Just change gear oil

my guess is your overly concerned or "babying" it into gear.
for lack of a better description its a mechanical slam shift arragment.
there is no slip type clutch.
shift quick and firm.
it will make a clunck when it goes into gear.
that is normal, what you dont want is to hear it chatter

 

[Ray Neudecker]

Re: Noise when changing gear - Just change gear oil

Be sure the engine is idling at 1000 rpm's or less and as Rodbolt said firmly put it into gear.

 

[joserrr2]

Re: Noise when changing gear - Just change gear oil

Hi, if engine was put in gear using the muffs it will that noise because it has no load and the prop will spin out of the water.

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

I just checked this afternoon and the idle is just around 1000 RPM. As Ray and Rodbolt suggested, I put firmly into gear and the noise reduced heaps. However, there is still a noise there and that irritates/worries me. I will see if the noise will go away when I put in gear when in the water. Now I just wait for the next long weekend to do this. Does your motor make soft grinding noise when put in gear out of water (using muffs)? Anyone?

 

[Yamajoe]

Re: Noise when changing gear - Just change gear oil

Ok, when you have the motor in the water (not muffs) adjust your idle to 650- 750, you should notice a considerable decrease in noise, shifting in gear at 1000 rmp is still on the high side.

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

Thanks Joe, now I will try and obtain the knowledge to adjust the idle RPM. I'm a fast learner so please show me (I have purchased a repair shop manual on eBay and am still waiting for it to arrive). By the way will low idle RMP cause the motor to stall easier at low RPM?

 

[Yamajoe]

Re: Noise when changing gear - Just change gear oil

The recommended low idle (retard) rpm spec. and how to adjust will be set out in your manual. remember, the rpm will be slightly lower in the water than on muffs, that is why these adjustments are best done when you have launched the boat. the motor will stall when you reduce rpm below the recommended retard rpm, if it stalls at or near recoomended rpm, usually, it is a sign your carbs need a clean, link and sinc needs attention, faulty reeds, low compression and so on;

 

[Silvertip]

Re: Noise when changing gear - Just change gear oil

If you are "sliding" the shifter into gear -- stop doing that!! What you are hearing is the clutch dogs grinding against each other. Shift with authority. Snap the shifter into forward or reverse. A very slight "chunk" is normal when shifting is done quickly. The ratcheting noise will wear the clutch dogs and you will then be back here wondering why the motor jumps out of gear. If you have driven an manual transmission car, sliding the shifter into gear slowly is like slipping the clutch on a car.

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

Thanks guys, all making sense to me now. I was thinking that being careful when putting to gear is better. No wonder my boat license instructor put his boat quickly into gear. I thought he was just showing off. The noise i hear now when doing it fast is more like a clacking noise than a grinding.

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

Took the boat to the bay today. It was a bit rough so I only had about 4 hours boating inside the bar. No more noticeable noise when shifting now. Of course, I did it fast. Thanks guys. Now should I check the new gear oil I just changed the other day to check for sign of water? I realized that the old oil was a bit pale yellow when I changed it. Also the previous owner only had it changed once at the first 10hr break-in service and it was almost 2 years ago!

I have opened a new threat for the following question: "my motor is harder to start in water than on muffs". Plz help me with that threat too. Thanks for sharing your valuable knowledge. Very much appreciated!

 

[Yamajoe]

Re: Noise when changing gear - Just change gear oil

yes drop the oil and use new gaskets on both screws

 

[kvan64]

Re: Noise when changing gear - Just change gear oil

Yes, will do that. The only thing is I need to be careful this time as it felt not tight enough but when I tighten them a bit more, the gaskets got deformed and broke. What should I do if I don't have a torque-spanner? I have bought 10 more spare gaskets for just in case.

 

[Yamajoe]

Re: Noise when changing gear - Just change gear oil

i just hand tighten with my impact screw driver and give one measured tap with a rubber mallet seems to work all the time for me.