Yamaha 40hp Rattle Noise, Video

[Ruggybuggy]

The motor is a 2004 Yamaha 40tlrc that has about 15 hours of use. If you listen carefully you can hear a rattle noise as soon as it put into gear (forward or reverse) and as soon as you get off idle the rattle stops. It doesn't rattle in neutral. Noise seems to be coming in the area between the lower unit and power head. I took the lower unit off and found nothing unusual. Lower unit oil is clean and nothing on the magnet. I inspected the water pump housing and everything looks fine. I put a coating of grease on the input shaft and put it back together and still have the noise. It's not the shifting rod rattling because if I grab it while running the noise is still there. The power head runs fine with no overheating issues.

I'm starting to believe this is a normal noise. Can anyone verify. I just install the motor on the boat and haven't used it yet. Just want to make sure this is nothing to worry about. Thanks for any help in advance.

Dave

http://s392.photobucket.com/albums/pp10/Ruggybuggy/?action=view&current=SDV_0017.flv

 

[CodHunter]

Re: Yamaha 40hp Rattle Noise, Video

It is a 2-stroke, right?
I can't hear anything unusual from the video.
However, the noise might change if your boat is in the water. When in the water, the noise from the exhaust pipe will be reduced, a possible rattle could be more clear and better audible.

Mike

 

[Ruggybuggy]

Re: Yamaha 40hp Rattle Noise, Video

Yes it's a two stroke. If you listen carefully you can hear it. If it's difficult to hear I'll try putting it in a barrel.

 

[CodHunter]

Re: Yamaha 40hp Rattle Noise, Video

Sorry, can't hear it! Put it in a barrel and post again.
Mike

 

[99yam40]

Re: Yamaha 40hp Rattle Noise, Video

pull the prop off and try running without it to see if the noise is still there.

The tell tail stream is not very strong, my 1999 40 puts out a lot more while on the hose, you might want to change the impeller

 

[brummo]

Re: Yamaha 40hp Rattle Noise, Video

Let me guess, you only hear it in gear. I have an F40tlry and I hear the lower unit on muffs when it is in gear too. Never hear it in the water. My friend has a Suzuki, I hear his too when it is out of the water in gear.

 

[Ruggybuggy]

Re: Yamaha 40hp Rattle Noise, Video

pull the prop off and try running without it to see if the noise is still there.

The tell tail stream is not very strong, my 1999 40 puts out a lot more while on the hose, you might want to change the impeller

I was kind of thinking the same. The Evinrude 25 that was on the boat before had a much strong stream. When I had the lower unit of I check the impeller and it seemed fine but I'll order a new one and change it.

Thanks for point that out.

 

[Ruggybuggy]

Re: Yamaha 40hp Rattle Noise, Video

Let me guess, you only hear it in gear. I have an F40tlry and I hear the lower unit on muffs when it is in gear too. Never hear it in the water. I hear my friend has a Suzuki, I hear his too when it is out of the water in gear.

Yup, only while in gear. This is the first motor I've hear this on and at present I have a Evinrude 25, Yamaha 15hp 4 stroke and a 2008 Tohatsu 4 stroke. I'll put in a barrel as other have suggested but I was concern that even if I don't hear the noise there still might be a problem. So what actually causes this rattle noise? That's what's puzzling. Gear noise?

 

[brummo]

Re: Yamaha 40hp Rattle Noise, Video

Yup, only while in gear. This is the first motor I've hear this on and at present I have a Evinrude 25, Yamaha 15hp 4 stroke and a 2008 Tohatsu 4 stroke. I'll put in a barrel as other have suggested but I was concern that even if I don't hear the noise there still might be a problem. So what actually causes this rattle noise? That's what's puzzling. Gear noise?

That is my guess. Since there is no load on the prop/ motor it is like free wheeling. If you put your car/truck on jackstands and put it in gear at idle, you get the same kinds of noises gears rocking back and forth in the pumpkin etc... I'm just using the best analogy I can think of.

 

[99yam40]

Re: Yamaha 40hp Rattle Noise, Video

I was kind of thinking the same. The Evinrude 25 that was on the boat before had a much strong stream. When I had the lower unit of I check the impeller and it seemed fine but I'll order a new one and change it.

Thanks for point that out.

pull and check to make sure housing is OK.
Get the kit it is only a few dollars more and you may need the cup and plate that is in it

 

[Ruggybuggy]

Re: Yamaha 40hp Rattle Noise, Video

I took the lower unit off again and changed out the impeller. I would have changed out the cup and plate as 99yam40 suggested but didn't read this till after I bought the impeller. On inspection the cup and plate looked like new. There were absolutely no marks on either part. After putting back together I ran it in a plastic garbage can and stream was strong, better then with the hose on it. Thanks again 99yam40, saved me some unwanted grief at the lake. When I put the motor in gear I couldn't hear the rattle while in the can. I going to assume that without some load on the prop the noise was gear rattle caused from the Yamaha's 3 cylinder power strokes.

Here a picture of the impeller that I thought didn't look to bad. On inspection each of the blades bent over very easily. It's strange that such a low hour motor would need an impeller. I suppose it's because of age, 6 years old.