Bent propshaft

[ohsoslow]

Hi guys, Sorry if I'm doing this wrong, but new here!

Basically I've got a 1997 225hp saltwater series, and the propshaft is bent, as in you can see the end of it moving up and down when you turn it by hand. I spoke to an outboard mechanic, who said not to worry about it, but surely this will be causing vibration issues, flogging out seals and bearings etc? Not to mention affecting performance?

While working on it today, I tilted the motor down, and oil (yellowy colour) dribbled out of the holes (one on either side) above the top oil fill plug in gearbox. I thought they were water holes?

My questions are, should I be worrying about it? Is the oil leaking out the top a sign that the seals are knackered?

And if I need to get a new prop shaft, is it possible that I can do it myself? (I'm an engineer, and used to be a car mechanic, so have a reasonable idea of whats what) If so, What parts will I need? Prop shaft? new bearings? new seals?

Sorry for the long winded post, just trying to explain myself, and as I'm in New Zealand, would need to order the right parts first time, so the boats not stranded for months waiting for more parts to arrive!

Thanks for any help!

[robert graham]

If it doesn't vibrate, then maybe go ahead and run it, as is. Check your lower end fluid for leakage of seals. You could probably change the prop shaft, but that bearing carrier may be difficult to remove, especially if motor has been in saltwater all these years. If the motor is running O.K., I'd be prone to just leave it alone. Good Luck!

[ohsoslow]

Hi,

Thanks for the reply!

I'll try and get it out on the water this weekend and take it for a run to see if theres any vibration. Also will check oil level!

Will report back with my findings!

Thanks

[ausnoelm]

not 100% sure I read your description right, but I would be draining the lower unit oil the make sure it does not contain water, how much is the shaft bent? lots have a tiny bit of "runout"

[ohsoslow]

I'm hoping that there is oil in there to drain out! :P I'm at a bit of a loss as to why oil (possibly gearbox oil) would be draining out from those holes above the fill plug!

As far as the runout goes, I haven't put a DTI on it, but from the looks of it I'd say about 1mm of runout at the tip. Clearly visible to the eye.

[99yam40]

Smell the oil coming out of the holes. The lower unit oil smells a lot different than unburnt 2 stroke oil

[Papa Basscat]

Its just a guess but if there is any internal damage associated with the bent shaft "that would cause loose metal shavings in the lower unit" then that metal would damage the upper LU seal and allow it to leak oil. The lower seal will be next. I just bent my shaft last night too. SUXS

[ohsoslow]

Ok, have just drained the gear oil. Still had plenty in there, at a guess a litre or so came out. How much is required to fill? The oil that was in there, was not pretty!! Clearly hadn't been changed in a while, but doesn't appear to have any water in it. There was a few metal filings on the drain plug, but nothing too impressive.

So my plan is to put some 75W-90 gear oil in, and give it a run, then drain it again, and fill with Yamaha oil. And I guess just keep an eye on the oil level?

Oh, and the oil coming out of the holes was definitely not 2 stroke oil, it appeared to be gearbox oil. BUT it was clean, where as the stuff in the gearbox was not nice at all. So I'm at a loss as to where the oil came from! I think I might just ignore it and see if it happens again.

[Bluefish]

Sounds like you just got this engine? Could it be fogging oil you see dripping.

[99yam40]

I agree,
Did you give the stuff a sniff to see what it smelled like?gear oil can be identified by smell.
I could be that the motor is not burning all the fuel oil mix and it will show up looking like dark oil or it might be fogging oil when it was put up for storage

[ohsoslow]

Yeah I just got the engine, has been sitting in storage for a few months, so maybe it is fogging oil? I've never seen fogging oil before? It was a yellowy colour, much like clean gear oil. Unfortunately I didn't smell it at the time, just wiped it away. *smacks head*

[ohsoslow]

Alright, finally managed to get it out on the water and give it a decent run! Basically at 1100rpm, the boat/motor vibrates and shakes a fair bit. But the rest of the time throughout the rev range it seems to run mint! So I think I'll just ignore the bent propshaft for now!

Thanks for the help with it guys!

[throrope]

My prop shaft is also bent. I'm going through the process of doing this one myself due to lack of trust with the only Yamaha shop in the area. Rodbolt17 provided good guidance. The obstacle I'm facing is specialty spanner wrench and puller. They cost a fortune and I don't know where to get them.

During a trip to the local plumbing supply, I got the wild idea to make a wrench out of a 2-1/2" to 1-1/2" black iron reducer, nipple and plug. I bought a replacement ring nut, placed it on the reducer and spray painted the pattern. Using a flange fitting screwed screwed to a work table to hold the assembly, I ground off everything except three nubs and repeatedly matched the nut until I had a wrench. After an afternoon with a hand held grinder, 80 grit wheels and a few cold ones, it works like a charm. It turns off with a 14" pipe wrench and I plan to use the 1" square plug to torque to spec.

I'm still working on the puller.

IMHO, if you can build a relationship with a seasoned marine mechanic at a good shop, that's a better route.

I agree with your decision to run as is. I doubt the job will be less expensive if it gets worse and you may hit something again in the meantime.

BTW, ours is more than 1mm out and does not noticeably vibrate. I suspect something else is up especially since vibrations due to imbalance usually gets worse with increasing rpms.

[robert graham]

Alright, finally managed to get it out on the water and give it a decent run! Basically at 1100rpm, the boat/motor vibrates and shakes a fair bit. But the rest of the time throughout the rev range it seems to run mint! So I think I'll just ignore the bent propshaft for now!

Thanks for the help with it guys!

Be sure and refill your lower unit with Marine Outboard Lower Unit Oil, not just automotive gear oil. The Marine oil has special additives in it for friction and water. Hopefully you're O.K. on the bent propshaft!

[Motorman]

My prop shaft is also bent. I'm going through the process of doing this one myself due to lack of trust with the only Yamaha shop in the area. Rodbolt17 provided good guidance. The obstacle I'm facing is specialty spanner wrench and puller. They cost a fortune and I don't know where to get them.

During a trip to the local plumbing supply, I got the wild idea to make a wrench out of a 2-1/2" to 1-1/2" black iron reducer, nipple and plug. I bought a replacement ring nut, placed it on the reducer and spray painted the pattern. Using a flange fitting screwed screwed to a work table to hold the assembly, I ground off everything except three nubs and repeatedly matched the nut until I had a wrench. After an afternoon with a hand held grinder, 80 grit wheels and a few cold ones, it works like a charm. It turns off with a 14" pipe wrench and I plan to use the 1" square plug to torque to spec.

I'm still working on the puller.

IMHO, if you can build a relationship with a seasoned marine mechanic at a good shop, that's a better route.

I agree with your decision to run as is. I doubt the job will be less expensive if it gets worse and you may hit something again in the meantime.

BTW, ours is more than 1mm out and does not noticeably vibrate. I suspect something else is up especially since vibrations due to imbalance usually gets worse with increasing rpms.

I saw your May 2010 prop shaft removal post. Great solution for nut removal !
I have 1992 - 225 Yamaha - Nut & lock ring is removed. How to remove prop shaft ?
What puller did you use ? Just pull on prop shaft ? or do you have to remove bearing housing first ?
What is procedure to get assembly out of housing ? Thanks for any help !!