Gear lash noise? Related to hard shift into neutral?

skydiveD30571

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5.0GL-H with SX-A

1) I've had a constant noise exactly like in this video for a year now. It is pretty noticeable and clearly audible in the water:

MOV02448.flv Video by mprentice1804 | Photobucket

Does that sound like gear lash? It only happens in neutral, and never when the engine is first started. It's almost always after a run when I begin to hear it. I read an old post by Don that mentions it occurs from parts breaking in.

2) The last couple days on the water, shifting into neutral from forward has gotten much tougher. From reverse to neutral is easy. Also, shifting into gear has more of a clunk than I remember, but I can't compare since this is my first boat. I'm pretty sure it used to be smoother though. Disconnected shift cable at the drive, and drive shifts easily by hand. Control still had some stick to it, but not as much.

According to the tach, idle rpm is about 700 in neutral and 600+/- in gear. I plan to confirm this by finding a shop tach online since I can't find anything locally. It is a carbed engine so naturally the idle isn't super smooth, but I can't hear any problems with it. If I drop the idle speed at all it begins to bog down so it is pretty low. Changed gear lube this spring to Amsoil 75/80w90 synthetic marine lube. New TFExtreme cables less than a year ago.

I imagine these two things are not related, but I can't seem to figure either of them out. New cables helped the shifting problem, but it's back already. The only thing changed over the off-season was the gear lube (had Merc green/blue in it before).
 

Don S

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Re: Gear lash noise? Related to hard shift into neutral?

Might want to check your tach, that sounds more like 450 than 700 rpm.

It sounds like a gear lash rattle. Shouldn't be near that much rattle with a gas engine.
 

skydiveD30571

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Re: Gear lash noise? Related to hard shift into neutral?

Just ordered a shop tach to find out how truthful the dash tach is.

Do you mean the video sounds like 450, or the fact that I can't idle slower without bogging? Just fyi that video isn't my drive, but the only video I could find which clearly demonstrates the sound. Is that gear lash rattle causing internal problems which need to be addressed? Thanks Don.
 

Don S

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Re: Gear lash noise? Related to hard shift into neutral?

Sounds like 450 rpm or lower. May be why it rattles so much.
 

skydiveD30571

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Re: Gear lash noise? Related to hard shift into neutral?

Oh you mean the video. I'm not sure what his idle speed was. When my tach comes in ill check what my idle rpm is. Is gear lash rattling damaging or just an annoyance?
 

Don S

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Re: Gear lash noise? Related to hard shift into neutral?

I thought it was your video. :facepalm:
 

skydiveD30571

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Re: Gear lash noise? Related to hard shift into neutral?

No, but it might as well be. Its my drive model and identical sound. The only such video I can find anywhere.
 

skydiveD30571

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Re: Gear lash noise? Related to hard shift into neutral?

I got my shop tac in today. Put a reflective square on the circulating pump pulley and started up. Looks like my gauge is reading about 75rpm low at idle. I adjusted the idle screw to about 750 according to the shop tac (675 dash tac) and shifting seemed smoother and quieter of course. Now we just have to see what the idle speed will be once its in the water and tweek it from there. Does 750 on muffs sound about right?
 
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