F50 tlrx 1999 Yamaha rattle in lower

[gotboostedvr6]

I just bought a F50 and it has a rattle while in gear on the stand at idle with no load. There is no noise in neutral. I drained the lower unit oil and about 3/4 pint of clean oil came out, no metal shavings were visible or were found on the magnetic plug.

The noise is pretty audible, kinda like a clank clank. The gears aren't skipping. this noise is in forward and reverse.

Whats the next step? should i refill the oil to the recommended level and try again? 3/4 pint seems low.

 

[gotboostedvr6]

Re: F50 tlrx 1999 Yamaha rattle in lower

well the lower unit has been draining for the last 4 hours, i just refilled it and plan to run it again tomorrow. I think this time ill drain it into a stocking to catch whatever shavings that might be in there.

 

[jerkin]

Re: F50 tlrx 1999 Yamaha rattle in lower

Boosted, My F115 started doing the same thing when I went from an aluminum prop to stainless. I searched on here with no luck then posted about it and was told to make sure I put the thrust washer on, check the play on the shaft, etc. Everything looked good.

About a year later I found a post on a walleye board I frequent about the same thing and it also started when he switched to a stainless prop. A few people posted the same problem in that thread, one of them claimed to be a Yamaha mechanic who said he's seen it a few times but it doesn't seem to hurt anything. The few people on that thread all said it comes and goes with a prop change but no one mentioned any damage.

I don't put a ton of hours on my boat but I've been running it like that for about 3 years now with no problems. I don't really notice anything abnormal when I change the lower unit lube for the winter. I would also like to know what causes it but I never did find out.

 

[gotboostedvr6]

Re: F50 tlrx 1999 Yamaha rattle in lower

Did you hear the noise in idle or just in gear? also was this in the water only or on the hose?

The funny thing is i am running a 4 blade stainless prop.


Im gonna run it again and drain one more time.

 

[jerkin]

Re: F50 tlrx 1999 Yamaha rattle in lower

Same problem as yours, only happens in gear at low rpms. As soon as you give it a little throttle it goes away. I can't get my F115 to pump water on the hose(fried an impeller trying) so I have to do it in a tank so I can't say if it would do it with the muffs on or not. I'll bet ya a dollar to a donut it will go away if you put an aluminum prop on it though. Another thing I noticed was that it goes into gear a lot harder with the ss prop also, but like I said I don't find any debris or anything when I change the lower unit lube.

 

[zzzzz]

Re: F50 tlrx 1999 Yamaha rattle in lower

Yamahas are notorious for being "rattley" at low RPMs...we hear that complaint all the time and - yes the stainless props increase the noise

 

[gotboostedvr6]

Re: F50 tlrx 1999 Yamaha rattle in lower

Well refilled the lower ran it with and without prop. Noise present only with prop installed.

Also ran it in a bucket no noise in gear under load... all is well

 

[andymach23]

Re: F50 tlrx 1999 Yamaha rattle in lower

My new F40 did this on the hose at the dealer when I bought it. The dealer sent the lower unit way as a precaution, as a warranty item. The new one (which I saw being unpacked) did it as well. They fired up an F100 on the hose and put it in gear and it did it as also. I've 120 trouble free hours on this motor now.

I think Rodbolt posted about this a while ago and mentioned that it was to do with the Yam gearbox design and that it needs water pressure to stop the noise. Sorry about the non-tech explaination.

 

[jerkin]

Re: F50 tlrx 1999 Yamaha rattle in lower

Andy, are you saying yours does it on the hose but not in the water?

Mine does it in the water, so the resistance of the water doesn't stop it. Not sure if it would do it on a hose or not but it probably would.

Mine is pretty loud with the ss prop on it, you would swear the motor was throwing a rod. Put the aluminum prop back on and you don't hear it, weird.

 

[gotboostedvr6]

Re: F50 tlrx 1999 Yamaha rattle in lower

Hmm i also have a Yami 2002 25 hp 4stroke and it makes the noise on the ears with the stainless prop. No noise with the aluminum.

 

[andymach23]

Re: F50 tlrx 1999 Yamaha rattle in lower

Andy, are you saying yours does it on the hose but not in the water?

Mine does it in the water, so the resistance of the water doesn't stop it. Not sure if it would do it on a hose or not but it probably would.

Mine is pretty loud with the ss prop on it, you would swear the motor was throwing a rod. Put the aluminum prop back on and you don't hear it, weird.

Yes, mine does it on the hose in gear. There is no noise evident when the motor is running in the water. This is with the stock aluminium prop.

 

[rodbolt]

Re: F50 tlrx 1999 Yamaha rattle in lower

well I dont claim to be a yamaha tech, you can look at my picture on the yamaha Master Tech website,
but I have posted numerous times about the rattle, what causes it and why.
and yes other brands rattle as well.
hunt about the forums a bit, I did a long post about 2 weeks ago on the issue.
then you will understand why it goes away with the prop off and gets worse with a stainless prop.
and you will also understand why other brands rattle too.

 

[jerkin]

Re: F50 tlrx 1999 Yamaha rattle in lower

Rodbolt, I found the post you mentioned from a few weeks ago, thanks for bringing that up, it's good information. In that post you are referring to the noise when in gear with the muffs on. My engine does it in water also, is this the same thing?? Also, do you agree with the Yamaha guy from the walleye thread I mentioned from a few years ago who says it won't damage anything even in the long run? I would go back to the aluminum prop if I had to but the stainless one sure performs better. Thanks.

Here is a link to Rodbolts' post from a few weeks ago explaining the cause of the rattle in case anyone wants to read it.

http://forums.iboats.com/showthread.php?t=245763&highlight=rattle

 

[andymach23]

Re: F50 tlrx 1999 Yamaha rattle in lower

I just had another read at Rodbolt's post. An excellent technical explaination.

I remember back a couple of years ago when I was looking at this with my F40, I tested it out with a Mariner 60hp 2 stroke and it did not rattle. At the time I was disappointed that it didn't rattle. I'd hoped to say 'see they all do that'.

Looking back now it just confirms what Rodbolt says, that it's particular to 4-strokes.


Maybe Rodbolt's post should go into a FAQ section?

 

[rodbolt]

Re: F50 tlrx 1999 Yamaha rattle in lower

some two strokes will do it as well.
but always remember the crankpin on a two stroke recieves a power pulse everytime the piston reaches TDC and a four strokes piston every other time.
the other cause for gear case rattle on yamahas is someone left out or incorrectly installed the 2 spacers,wave washer and lock collar assy on the water pump impeller. thats its sole purpose in life.
either way it doesnt hurt anything but can be annoying .
I tried a 4 blade 19" on my F150, the rattle at an in gear idle drove me nuts so I went back to the 3 blade black yamaha SS and it went away,
why the difference in the two props? beats me, its something to do with blade design though.