Prop won't spin, hit a rock. HELP

JVCar22

Cadet
Joined
Aug 10, 2010
Messages
26
Hi everyone,

I posted this under prop questions but didn't get any response, so I figured I'd try here.

Yesterday while on my boat I hit something. A rock, cable, anchor, something.. I lost all power to my prop. The engine was running fine except the prop wouldn't spin. When I would put it into reverse the boat would over heat and stall out. I check to make sure there wasn't anything wrapped around it, but it looked fine. While in neutral the prop spinned freely.

When we got towed back to shore, I took the boat out of the water and put the boat into gear (being shut off of course). I Tried spinning the prop while in gear and it made a weird grinding noise. When I tried spinning the opposite direction that should've been locked it wasn't.

I was told by someone that I'll have to replace the whole lower unit.

Does anyone have any ideas?

The outdrive looks fine. You can see that my SS Prop clipped something because it got grinded a little bit on the blades.

Thanks everyone.
 

jkust

Rear Admiral
Joined
Aug 2, 2008
Messages
4,942
Re: Prop won't spin, hit a rock. HELP

Pull the prop and look the hub. Sounds like you 'spun' it. Cheap to fix if you didn't cause internal damage to the gears. Because the stainless is so strong the gears can be damaged before the prop so the hub will do it's job and be damaged first. It takes all but 5 minutes to pull a prop with a 2x4 and crescent wrench in a pinch. A new hub isn't too expensive. I am not quite getting the overheat in reverse from a spun prop though.
 

JVCar22

Cadet
Joined
Aug 10, 2010
Messages
26
Re: Prop won't spin, hit a rock. HELP

When I put the gear into reverse and tried spinning the prop by hand it was real hard to do. It was barely moving.
 

sethjon

Senior Chief Petty Officer
Joined
Jun 8, 2010
Messages
692
Re: Prop won't spin, hit a rock. HELP

Hi everyone,

I posted this under prop questions but didn't get any response, so I figured I'd try here.

Yesterday while on my boat I hit something. A rock, cable, anchor, something.. I lost all power to my prop. The engine was running fine except the prop wouldn't spin. When I would put it into reverse the boat would over heat and stall out. I check to make sure there wasn't anything wrapped around it, but it looked fine. While in neutral the prop spinned freely.

When we got towed back to shore, I took the boat out of the water and put the boat into gear (being shut off of course). I Tried spinning the prop while in gear and it made a weird grinding noise. When I tried spinning the opposite direction that should've been locked it wasn't.

I was told by someone that I'll have to replace the whole lower unit.

Does anyone have any ideas?

The outdrive looks fine. You can see that my SS Prop clipped something because it got grinded a little bit on the blades.

Thanks everyone.

If the blades aren't bent and just scraped you may have gotten away lucky. Pull the prop. Check the hub. My guess is you will have to replace both. My suggestion would be get an aluminum prop because if it happens again the blades will break off easier than SS and save your OD. Thats the optimistic outlook. The OD very well may be shot but pull the prop first and don't panic.
 

Limited-Time

Vice Admiral
Joined
Mar 30, 2005
Messages
5,820
Re: Prop won't spin, hit a rock. HELP

Hi everyone,

When I would put it into reverse the boat would over heat and stall out.

Thanks everyone.

Its appears to be more than a spun prop. Did the engine over heat while idling??
 

JVCar22

Cadet
Joined
Aug 10, 2010
Messages
26
Re: Prop won't spin, hit a rock. HELP

Its appears to be more than a spun prop. Did the engine over heat while idling??

While idling, no. When I would put it into gear than it would overheat. Coolant started coming out of my reservoir.
 

Brewman61

Ensign
Joined
Jun 10, 2010
Messages
996
Re: Prop won't spin, hit a rock. HELP

Sounds to me like you need to have the outdrive inspected. A simply spun prop wouldn't cause any of the other symptoms listed.

I suspect by your description you have some lower unit damage, and it won't be apparent unless you have it checked.
 

JVCar22

Cadet
Joined
Aug 10, 2010
Messages
26
Re: Prop won't spin, hit a rock. HELP

Well we are going to pull the lower unit off tonight. And depending on what we see I might just try to find a rebuilt lower unit for cheap and put it on.

This is most likely in the lower unit though, right?
 

6meter

Chief Petty Officer
Joined
May 15, 2010
Messages
525
Re: Prop won't spin, hit a rock. HELP

Take the cap off the top of the OD. Spider gears stripped? NOT supposed to hear or feel grinding when turning prop. Overheating because impeller shaft not turning? Make sure your coupler is ok also. By what you have said, its inside the OD. Bummer. This is based on you having a Mercrusier OD.
 

JVCar22

Cadet
Joined
Aug 10, 2010
Messages
26
Re: Prop won't spin, hit a rock. HELP

Take the cap off the top of the OD. Spider gears stripped? NOT supposed to hear or feel grinding when turning prop. Overheating because impeller shaft not turning? Make sure your coupler is ok also. By what you have said, its inside the OD. Bummer. This is based on you having a Mercrusier OD.

Ok, I'll try that when I get home tonight.
When I put the gear into reverse and try to hand spin the prop in reverse it's really tight and makes a noise behind the prop like it's trying to spin but something is stopping it. And when I spin the prop in the forward direction while still being in reverse gear it spin and kinda clicks a little as it spins.
 

MolsonCanadian

Petty Officer 2nd Class
Joined
Jul 9, 2010
Messages
199
Re: Prop won't spin, hit a rock. HELP

Thats normal, when you try to spin it in gear, you're essentially trying to turn the whole motor.
 

jkust

Rear Admiral
Joined
Aug 2, 2008
Messages
4,942
Re: Prop won't spin, hit a rock. HELP

What are the details of your engine/drive, boat, year etc?
 

JVCar22

Cadet
Joined
Aug 10, 2010
Messages
26
Re: Prop won't spin, hit a rock. HELP

Dont' know too many specifics

1987 Searay Seville
Mercruiser I/O
 

dingdongs

Chief Petty Officer
Joined
May 29, 2009
Messages
649
Re: Prop won't spin, hit a rock. HELP

the verticle shaft has splines on and may have sheared off hence when the engine is running the verticle shaft is not spinning which the water pump is connected to.drop lower end and see if splines have been left in gear in upper and report back.shaft that prop sits on may be bent too.remove prop and spin and you may find some results.get yourself a depth sounder as there not as expensive as hitting the bottom.
 

JVCar22

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Joined
Aug 10, 2010
Messages
26
Re: Prop won't spin, hit a rock. HELP

Just went down to a marina over here and explained to them as well to see the feedback they had for me. He said it could possibly be the engine coupler. I'm assuming this is a big job that costs $$$$$$$$$$$$

Tonight first thing I'm going to do is start the engine and check to see if the couple is spinning... if it is i'll be happy, than we'll take apart the lower unit.
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
Re: Prop won't spin, hit a rock. HELP

When I put the gear into reverse and try to hand spin the prop in reverse it's really tight and makes a noise behind the prop like it's trying to spin but something is stopping it. And when I spin the prop in the forward direction while still being in reverse gear it spin and kinda clicks a little as it spins.

If by spinning it in reverse you mean counterclockwise, then it should spin freely in that direction and lock when you turn it forward (Clockwise) when you are in reverse gear. Sounds like a more serious problem.:(
 

JVCar22

Cadet
Joined
Aug 10, 2010
Messages
26
Re: Prop won't spin, hit a rock. HELP

Yeah, I'm not looking forward to opening her up tonight end being scared by a big problem. The guy at the marina said it could be the engine coupler, but wouldn't I of sunk if it was? Wouldn't I be spitting water all over the place??

I think we're going to drain the oil and see if there's white milky stuff in it first. If there is than I'm going to just replace the whole lower unit I think. It has to be something more to make the water pump to stop working. If it was just the hub than I wouldn't of overheated.
 

stonyloam

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Messages
5,827
Re: Prop won't spin, hit a rock. HELP

Yeah, I'm not looking forward to opening her up tonight end being scared by a big problem. The guy at the marina said it could be the engine coupler, but wouldn't I of sunk if it was? Wouldn't I be spitting water all over the place??

No, all the coupler does is connect the flywheel to the outdrive. If it fails, all it does is uncouple the drive from the flywheel, either the rubber can brake loose (you would probably smell hot rubber) or the splines in the coupler can fail. The fact that it overheated probably means that the driveshaft that connects the drive housing (upper) to the gearcase (lower) stopped turning, and your impeller stopped. In either case it is not good.:(
 

JVCar22

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Messages
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Re: Prop won't spin, hit a rock. HELP

So do you think I am correct by saying it is probably not the coupler??

We were thinking that when I hit the object in the water that it broke my shaft which sent pieces into the impeller and jammed it. If so we should see white stuff in the oil. Am I pretty much thinking in the right direction?

Replaceing the lower unit should fix all these issues, right?
 

stonyloam

Vice Admiral
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Messages
5,827
Re: Prop won't spin, hit a rock. HELP

So do you think I am correct by saying it is probably not the coupler??

Probably. As for the rest, won't know till you get a look inside. The impeller stopped (if it did) because the vertical driveshaft (from the upper to the lower) that drives it stopped. The problem could be in either the upper or lower. Good luck.
 
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