Broke off piece of lower unit on motor

[The Quadfather]

OK, well.. had my new boat for only a few months, and today I really screwed up.
My concrete slab/driveway has a 6" drop when you pull off the driveway, there is a drop into earth. Normally when I pull the trailer over this area, I ALWAYS have the motor trimmed up, not in a down position. Today I was leaving for early AM fishing, I had a friend with me, and was distracted.
When the trailer went off the concrete, the bottom of the lower unit of the Suzuki 40 hp motor, hit the concrete HARD. The dagger looking portion which maybe is called the Skeg? Anyway, it is there to protect the prop. This piece had a piece of it break off. The majority of the piece still on the lower unit is still 90% there. I could tell it would not effect my steering at all, but was traumatic to the motor itself.

Anyway, 2 questions.. anyone have experience with this piece getting broken? What is involved with a fix?
Also, boat ran just fine, although we trolled for 3-4 hours.. then at one point I was at full throttle for quite a ways. Motor ran just fine as it should.

On the way back into the marina, I went up in speed, and after a moment there was a change in the sound of the motor, and what felt like a loss of propulsion. It felt almost like it slipped into neutral for a moment? I backed way off the throttle. Everything was cool again... then moments later went back up in speed, same thing happened. After getting home I thought maybe I had the trim set improperly, but no... it was the same as when I first went full throttle early in the AM. I wound up limping back to the marina at 8 MPH.

Any thoughts on if I did some kind of damage internally with that hard impact on the lower unit?

Thanks in advance

[hlindsay]

I had a 90 hp yamaha that did not stay up when backing down a ramp and broke off about 2 inches of the skeg. It can effect steering but shoud not effect how the motor runs, so you may have a second problem with the motor. As for the skeg, they can be repaired by a shop welding on a part. That would be the high $ way I think. If you do a quick search for replacement skegs. You will see something like I got (I think from Amazon) it bolts on over the broken skeg and was not hard at all to install. It worked fine for me for years until I traded in the boat. If you haven't lost too much of the skeg you may not even need that. You could just grind it smooth and be ok.

[Mike Carey]

My first boat had missing chunks of skeg for years as I learned the hard way about power boat operations, LOL. May be a non-factor. NOt sure what was going on with your return home issue.

[hewesfisher]

Replied to your post report but will here to. It can be repaired, but I advise you take it in and have your dealer look at it to protect your warranty. Make sure your dealer provides you with a copy of whatever they tell you. The picture you posted in your report shows you still have a full length skeg, just part of the trailing edge is gone, so you don't need to worry about it affecting steering. Sometimes shock can damage internals, if no odd noises, and no leaks, dealer will probably suggest just having it repaired.

Your comment that later in the day that engine pitch changed and you experienced a loss of speed could possibly be related. For what engines cost these days, it's worth your time to get it checked out and documented.

[The Quadfather]

Thank you guys-
Hlindsay, that looks like a great option on the Amazon skeg replacement. I checked it out.
Phil, you have a good point though on the dealer documenting etc. I will go run the boat in a lake, and see if it was a fluke or something on my motor function via the previous return trip yesterday. It’s even possible I had the trim way out of proper setting. This is the first time I’ve had trim controls, and I get distracted when I have new people in the boat who aren’t boaters.

[Amx]

On my first motor, when I had it on my second boat before buying a new motor for the new boat and putting the old motor on the old boat - fixing the transom and selling it to my brother, the skeg broke completely off, all of it, with about 1/8th to 1/4" stub left. It didn't effect the running or steering at all. I did buy a replacement skeg, but never had it welded on. My brother never had any problems for the years he owned the boat. It was a 75 hp.

[rseas]

"On the way back into the marina, I went up in speed, and after a moment there was a change in the sound of the motor, and what felt like a loss of propulsion. It felt almost like it slipped into neutral for a moment? I backed way off the throttle. Everything was cool again... then moments later went back up in speed, same thing happened. After getting home I thought maybe I had the trim set improperly, but no... it was the same as when I first went full throttle early in the AM. I wound up limping back to the marina at 8 MPH."

First, I'm sorry to hear about your misfortune. It may sound odd but I have a heck of a time when somebody is helping with all things boating. If I get out of my routine I am lost and can easily forget things.

Regarding the situation described above; the prop spun the hub. It may be coincidental or maybe the missing chunk of the skeg has changed water flow and load on the prop. I recently had the same thing happen with the mail boat. I had to call Vessel Assist to get towed back into Skyline. Years ago I had a big offshore sports fishing boat. It was so heavy that even with a big commercial out drive about once a year it would spin a prop.

I solved the problem by having 3 props on rotation. One installed, one newly rehubbed spare on board and one to be rehubbed. As part of my annual maintance the recently rehubbed prop was swapped out for the running prop, newly rehubbed went on board as the spare...

Rehubbing a prop is pretty cheap. Probably 40-80 bucks for your prop depending on shop. It is a pretty basic process; press out the old hub, clean and then press in a frozen hub.

[The Quadfather]

Randy, thanks for that info about ‘Spinning a prop’
If I understood it right, it sounds like you can damage whatever mechanism actually applies torque spin to the prop.. and then suddenly that mechanism is spinning, but prop not engaging.. no prop spin?
Anyway, we’ll see.
I have never run a motor in a garbage can, but I probably could get some high RPM’s in the driveway, see if it repeats.
From their to Skagit dealer.

[rseas]

Master Marine?

[The Quadfather]

Yes

[rseas]

Either way I would have them check it out. A new prop shouldn't spin the hub and would probably be replaced under warranty. If it is not the hub it is likely a mechanical problem that would be covered under warranty.

[rseas]

"Spinning the hub"; most props are built with an internal spline that slides on the lower unit prop shaft. The spline is molded into a rubber donut that is pressed into the actual prop body. The failure can occur at the friction or interference fit of the rubber donut with the prop body or as a failure of the bond between the spline and the rubber donut.

The rubber donut provides two functions: 1, to reduce vibration. 2, to help prevent damage to the motor and gears in the event of an impact while the motor is running and in gear.

[18ftTrophy]

Hey Chris, What rseas is describing can be checked by putting the motor in forward gear with out the motor running. Go and try to spin the prop, it shouldn't rotate, if it does it's spun.

[Sideburns]

Googled the suzuki 40hp original prop info, rseas was is correct, you should have a pressed in rubber hub if the prop is original. Press-in hub # : 58120-88L00. -Some aftermarket props have no replaceable hub though!

Checking the prop hub by hand, out of the water, for signs of a spinning hub might be difficult. The smallish 40hp engine could just turn over instead of providing enough resistance to slip the rubber hub, might have to hold the nut with a wrench to keep engine from rotating. Could be obvious though... like visibly torn/damaged rubber. (from the back, look around the outside of the mounting nut...better yet, take the nut and washer off) If unsure, maybe use a paint marker to mark nut and prop orientation, go drive it and then check to make sure the marks are still aligned.

The other possibility. Propeller ventilation (sometimes called cavitation). This is what you feel and hear when you forget youre still trimmed up and trying to accelerate at low speed. Its usually loud enough to hear over the engine. Just like a damaged prop, (is that a ding in the prop in your pic?) a damaged skeg can cause ventilation problems. From your description this is not as likely though.

Bottom line though.... It probably wouldn't hurt to have a spare prop anyways. Kinda like having a spare tire.
http://boatpropellers.iboats.com/Suzuki ... =236582310
Less than 100 bucks includes the integral rubber hub. If that solves your problem, great, touch up paint the skeg, and order a new hub for your (old) spare prop. https://www.iboats.com/shop/suzuki-bush ... 88l00.html
I'll press it in for you next time you take me fishing...Lol...

[hewesfisher]

Pressed in hubs - still? Wow.

Don't waste time trying to determine if your hub is spun by running engine in garbage can because you aren't loading the prop. All it will do is make a heck of a mess trying to empty all the water from garbage can.

It's entirely possible you may have struck the prop same time you hit the skeg and that could be the reason the hub spun (if that's what is actually happening). As Rseas mentioned, you could also now have disturbed water flow around the skeg and are experiencing ventilation as Sideburns mentioned. Did you have the engine trimmed full in (down) when the RPM/engine pitch and speed changes were occurring? If you trim out too much you will experience ventilation even with no damage.

I copied your pic and there is a ding in the red circle (enlarge to see)...

Post a pic straight on from behind so we can see whether there is a "cant", "twist", or "bend" to the skeg. Also post some good pics of each prop blade.

[The Quadfather]

OK... my tail is in between my legs as I write this. I would not even come back on here and admit to this, but some of you put a lot of time into sending valuable information. In the end I actually learned a lot about props and hubs. And I think I've come to realize that a spare prop is a good thing to have in the tool bag.

So.. I took the boat out on Lake WA. tonight for shake down.
Although I did break my Skeg that morning, when I went out on to the Sound, I trolled low speed mostly. At one point I did run a long ways at high speed, (me driving) Then, I let my 20 y/o son drive the boat for a long ways. He has never driven a boat before, so very foreign. At the end of the trip, I was the last one to run the boat after he did, and that is when this whole thing started.

I realize now that when he was using the throttle, he must have squeezed the trim button, and had the trim maxed out or something, to cause the prop situation. Tonight, all was smooth going. This is my first boat that actually has a trim tab, so I am kind of not fully dialed into how it effects the boat, and I don't really think about it much. Certainly glad though for no costly repairs!

Thanks for the input everyone.

[rseas]

Good to hear Chris. I would still get the appropriate primer, paint and clearcoat to touch up the damaged area. It will help check any potential corrosion. I think West Marine has manufacture specific paints in spray cans.

[Sideburns]

Yep definitely need Marine / Suzuki aluminum primer and paint for touch up. saltwater water is tough on exposed aluminum. Aluminum is difficult to get paint to stick to, and requires specific paint supplies. Glad to hear that it was just trim/ prop ventilation.

Before buying a spare prop, let's talk about prop pitch.......

[hewesfisher]

Good to hear that Chris and I echo Rseas and Sideburns recommendations on primer & paint. Don't know if you have a tach, but to effectively play with props and pitch, you're going to need one.

[Sideburns]

I hear you on the tach. My first prop change without a tach and gps made me go slower. Guess and check gets expensive. Ive got a few options for portable tachs, but really wish I had a permanent one. Chris's boat doesn't have one either, I dont think.

If you're not harmonically in tune to the sound of your motor (mostly older motors like mine) weeds or prop damage can make you over rev your engine without knowing it.