Any lower unit experts?

[Jeff J]

I just opened up the lower unit on a Suzuki DF200A and found a mess. The prop and housing appear undamaged and the prop shaft is straight. Any ideas why it would strip out like this?

The lower unit was brand new last fall.

 

[lakensea]

Was this on a new engine, or was just the lower unit replaced? If so, why? How many hours?

 

[racerone]

Was this a new factory lower unit ?----Aftermarket ??

 

[Jeff J]

The engine is on a 23 foot tritoon and has about 1130 hours on it. The lower unit was changed because it was seriously damaged (skeg broken off, stainless steel prop nearly unrepairable on a severely bent shaft). I was told it hit a submerged tree at cruise power. I think the new lower unit has maybe 150 hours. I didn’t write down the time when it was changed and am estimating based off the oil changes. I last changed the oil on 7/12/2022 but didn’t notice any glitter in the oil at that time.

New lower unit came from Suzuki. I haven’t been able to find aftermarket or overhauled units for Suzuki.

 

[lakensea]

Did you change the gear oil after 20 hours of use? How much gear oil did you drain out prior to disassembly?

 

[Jeff J]

Last oil change was at 1131 hours so I am going to say that was the first oil change had at least 100 hours on it. This year’s manager was very bad about letting me know things were due. He let a couple of boats go over 170 hours between oil changes and he wasn’t checking levels.

I didn’t measure the amount of oil but it looks about right in the drain pan. There was not any water in it. I suppose I could find something to pour it into get an actual estimate before dumping it into the drum but I probably do about 25 oil changes a year.

 

[Jeff J]

I recovered about 36 ounces from the drain pan. Book calls for 38.7 ounces. I spilled some when draining the lower unit and I hadn’t let it drain completely before I opened it up. My guess is it was properly serviced.

 

[99yam40]

need to tear it apart to see if something came apart in the bearings or other stuff maybe, and got into the gears
I guess a tooth on a gear could of popped off, but that would not be likely

 

[Jeff J]

The bearings all appear to be where they should be from what I can see. Chewed up some of course. The big bearing in the rear housing is seized. I can’t see any gaps in the rollers.

I also thought about incorrect shimming but the timing bothers me for that unless I missed some serious glitter in the last oil change but I keep an eye out for that. We have a Yamaha that has been showing some glitter for 2 seasons. I need to order the driveshaft holder tool and the pinion nut is a little beat up.

Thinking back on it, I replace enough props in a season that I can’t remember which boat or when but it’s a rental fleet of 15 boats with mostly stainless steel props. Initially I was thinking about a bad part or incorrect shimming but I may have forgotten about a prop swap. It’s possible this lower unit could have suffered a prop strike that caused some internal damage. Props are so fast and easy to swap, even on the dock, that I don’t always invoice it. It would be rare for one to make it 150 hours and not need replaced.

 

[99yam40]

being rental, there is no telling what someone could have done to that unit

 

[Jeff J]

Yeah, rentals get abused. What got me was the lack of external damage. I actually had a maintenance complaint this summer about one boat not shifting into reverse while traveling forward about 15 mph
Maybe that dumbxxx got this one to shift.

 

[harringtondav]

It’s possible this lower unit could have suffered a prop strike that caused some internal damage. Props are so fast and easy to swap, even on the dock, that I don’t always invoice it. It would be rare for one to make it 150 hours and not need replaced.

Incorrect shimming is very unlikely in a factory built unit.
A prop hit with a SS prop can do this damage. It only takes one compromised gear tooth, then a chain reaction melt down follows.
I've owned SS props, but only use them when the water is high and floating logs are low. I'd recommend moving to only alum props. You have to change damaged props either way. Alum is less expensive and will give itself up before the innards are damaged.

 

[Jeff J]

I have made that recommendation myself. Someone else recommended the plastic props. The owner won’t budge because stainless looks good. Even pointing out the savings and the fact each lower unit usually puts a boat out of service for a couple of months didn’t make a difference.

I am returning a boat with another Suzuki today that I changed the lower unit on yesterday. That boat has been waiting for nearly 3 months for a lower unit. Suzuki showed one in the system when we ordered it and FedEx lost it. I finally gave up on the local dealers and located another last week myself but got ripped off on the shipping. The manifest shows 18 cubic feet and 170 pounds for a lower unit. I checked it before removing from the box. It should have been 11 cubic feet and 70 pounds. That’s a $200 difference in shipping price.