Think I hurt my gearbox

[Canuck 16]

Well, I knew it would happen sooner or later, just not the day I installed a brand new "merc " stainless steel prop!<br />I run over a decent size piece of driftwood about 1/3rd mile from the harbour. The motor (200 Yam) slowed a bit, then came back up to rpm's for the rest of the trip into the harbour. When I came off plane and idled into my slip, the motor was making a intermitent "growling" sound. Pull the shifter into neutral, sounds fine. <br />Pulled prop today, looks fine. Lousy plastic hub system, looks fine. Drained lube, no metal on magnet, or suspended in oil <br />Any ideas Guys???... Canuck 16.

 

[Canuck 16]

Re: Think I hurt my gearbox

No ideas?

 

[tony_cliffy]

Re: Think I hurt my gearbox

I've heard my motor "growl" for a few moments after coming off plane and idling. What you don't mention is if the noise persists or if you hear any other noises when you get back into the throttle. I'm wondering if you were just being overly focused on the motor noise following the event and possibly mistaking normal noise for something else. You didn't report anything unusual from your inspection.<br /><br />When you say growl do you mean a throaty exhaust or some mechanical noise of sorts from your lower unit?

 

[Canuck 16]

Re: Think I hurt my gearbox

Mechanichle sound. Goes away when I pull her into neutral. Dont think it was just me being overly focused since the two guys I had on board noticed it the same time I did.<br />I havent put the boat back on plane since I heard it, but I did idle aroun from my slip to the ramp and the growling sound was certainly there.<br />One of the local wrenches here told me " if theres no metal on the magnet, no point tearing down the lower unit".<br /><br />Canuck 16.

 

[BF]

Re: Think I hurt my gearbox

Hiya,<br /><br />that doesn't sound like great advice to me, from the wrench I mean... what you're suppossed to tear up the whole gear set before figuring out what bent/broke? Could it be that the propshaft got bent out of true a bit and that's causing gear or bearing noise? I'd wanna find that out before the gears get trashed. You don't wanna be stranded either!<br /><br />If you'll be making an insurance claim, I'd be pushing to get it tore down/fixed now. Ask your adjuster why you should have to go out and drive around just to break it more before they fix it (will end up costing them more).<br /><br />I probably wouldn't give that first wrench the business either if I had a choice.<br /><br />I don't know that prop either, but is it possible that the hub got tweaked just enough that it is out of true and unbalanced now? You could try putting your old prop back on to see.<br /><br />thats my $.02, good luck<br />Brent

 

[Canuck 16]

Re: Think I hurt my gearbox

BF, Funny you mention insurance, he did ask me if I had insurance.<br />I just finished flashing it up on the muffs in gear with both props on. Although harder to hear with the exta exhaust sound, I could definatly hear it, and feel it, leaning on the transom, with both props!<br /><br />Canuck 16.

 

[BF]

Re: Think I hurt my gearbox

Ya, in these parts I think you get better/friendlier treatment if it's an insurance job. Basically they know they'll be billing ~$2K for a LU rebuild (unless you decide to take your business elsewhere). If it's not through insurance, they know they'll probably end up with another customer who can't believe the price to fix it. (and be pushing them to do it cheaper somehow). If you had an open insurance claim and the green light from the adjuster to get it fixed (or at least estimated), then I don't think the wrench would blow you off (figuratively that is )<br /><br />The only LU i've rebuilt was for my V150 merc (broken driveshaft). It was an eye opener to see how expensive parts are. Even doing it myself, reusing what I could, and getting some good deals, it was still ~$600. Everyone was quoting me that much for just the new driveshaft. I found a good used one for <$200. I was able to reuse the gears on mine. Would've been hundreds more otherwise, so I definately got off easy.<br /><br />Anyhow. bummer that it really seems to be a LU thing. Good luck on figuring it out, & check the oil frequently. If you are covered insurance-wise, you might wanna talk to them soon. That way if it takes a week or two to really break, they can't claim it was un-related to hitting the wood. It's not a bad thing that you had witnesses in the boat either.<br /><br />Brent

 

[tony_cliffy]

Re: Think I hurt my gearbox

What are the chances he damaged his hub or propshaft without incurring visible prop damage? He does not mention any visible damage to the prop.

 

[Canuck 16]

Re: Think I hurt my gearbox

Spoke to a different marine mechanic about the noise and he told me to bring the LU to his shop and he would put a dial indicator on the propshaft for me. The results were 0.001". Dam near perfect.<br />As far as the prop hub, like I said earlier, I fired it up with the old prop on and heard the same noise/vibration.<br /><br />Canuck 16.