Transmission and stuffing box woes

[Manny]

Over the winter I rebuilt my Renault transmission (reversing gear as it's called in the manual) on my boat. The reason was because it would leak oil out of the rear seal. Well it turns out after sourcing the new correct seal it still leaks, although not as much, but close. Ironically today I discovered the front seal also leaks (I also replaced that seal). Has anybody tried any of the oil additives that claim to stop leaks? I'm wondering if those products work. Also I'm thinking of trying a different oil also. The manual calls for 10W-30 but I'm wondering if something like 15W-40 might be a little "thicker"?Also, my stuffing box is causing more grief. After replacing the shaft log hose and repacking it this winter I've been having problems trying to adjust it so it only drips once every twenty seconds or so while running but no drips when shaft is not turning. No adjustment seems to accomplish this, it's either always dripping or no drip whatsoever. A couple of people suggested that it may need to break in a little and I could then get it adjusted but that hasn't worked so far. My real concern is that matter how much I let it drip, it still gets extremely warm, even after light running. Anyone ever experience this? I'm not sure how warm it can get without doing damage but if I grip the stuffing box while running, after about 6 or 7 seconds I have to let go because it is too uncomfortable.Before someone suggest the PSS dripless shaft seal,let me just say the old Renault engine is just not worth that sort of expense. If I can't get these problems sorted, it's going to become my new anchor!!As ugly as it is hanging off my transom, I'm really starting to love my Honda outboard....Manny

 

[Manny]

One other thing...

The shaft/engine alignment is pretty darn close to what it was last year. When I removed the transmission for the rebuild the motor was left in place without touching the mounts. I have been planning on fine tuning the alignment but these other problems have taken priority.

 

[CalebD]

I would check the alignment of your shaft to the

stuffing box first. Then re-check the stuffing box packing and maybe even replace it again more carefully, if neccessary. As far as oils go 15W-40 might be a little 'thicker' than 10W-30 so what about a straight 30W oil instead? Our Atomic 4 gas model engine from 1967 seems to like Rotella T 30W oil when replaced bi-annually. For quicker cold starts I use a short spray of ether (starting fluid) on the air intake to get her moving. I doubt the ether works quite the same way on a diesel engine but you did not state whether your engine is gas or diesel powered.

 

[Ross]

Manny, I'll start with the almost obvious

Did you stagger the joints in the packing? If it is leaking and still getting hot there is too much friction in the gland. If you unbolt the shaft coupling from the gear box does it, or will it, stay pretty much in line? If not, does it want to move down or sideways?

 

[Stu Jackson]

What kind of packing did you use?

regular flax, teflon flax, green goop with flax or e-marine goretex?

 

[Ross]

ok nother obvious one

was there any sign of scoring on the shaft? As far as the seal are concerned you have two choices live with the leak or try a new pair of seals.

 

[Manny]

Ross -

There was a little scoring on the shaft, but not very deep (about the thickness of a piece of paper). When I installed the new shaft log hose, I cut it slightly shorter so the packing would not be in the same exact spot.At this point the engine is unusable, at least last year I could call on it in an emergency.Manny

 

[Ross]

Is it time to drill and tap and add a grease

fitting? It shouldn't get hot when it has water coming through it. Catch some of the water and see if it is also hot. You have to be putting work into the stuffing box to make it heat so there must be more than a little drag in there. With the gear in neutral does the shaft turn easily?

 

[Tim R.]

Don't do it

Adding a grease fitting is not a good idea Ross. The sea water will eventually wash all the grease out and then you will have water coming in through the fitting and the shaft will still be hot. Manny, align the shaft. Repack the box and screw on the packing nut hand tight so you have some leaking. Tighten just enough to cut the leaking sown to a few drops per minute. Run the boat(in gear) for an hour and readjust.Tim R.

 

[Ross]

Timr, Zerk fittings have a check valve and he

would have to use water proof, water pump grease. Any way I agree that shaft alignment seems like the most likely cause of the over heating stuffing box.

 

[Ctskip]

With all this overheating shaft talk

I wonder just exactly how much heat is acceptable and how much is too much? What is "hot" to one, is warm to another. Just how does one determine what is a acceptable temp? and how does one measure it? Melt a wax candle? Smoke? Untouchable? Just wondering. Keep it up, Ctskip

 

[Ross]

Probably melting wax is too warm. But if it is not

hotter than a paper cup of coffee feels than I doubt that it will come to any harm. The materials can stand the temperature, Flax is also linen and that you iron at 350 f or more, can tolerate that much heat and I have no concern about the bronze.

 

[Stu Jackson]

How hot is simple

if you can't hold your hand on it it's too tight and too hot. Unless you have calluses on your entire palm, that's a pretty good definition.

 

[Manny]

I'll try realigning the shaft

Then this winter I'll pull the transmission and take another look at the seals. Maybe I can hook a small electric motor up to and take a look at the seals leaking and see if there is a way I can fix it.Thanks for all the responsesAnybody have a ballpark figure on how long an alignment takes for someone doing for the first time?Manny

 

[Fred]

I don't have a clue on the transmission seals,

but I'm with Ross on the grease fitting for the shaft log. I've done it to a couple of boats, owned a few more that already had it done, and worked on several fish boats where the grease fitting was several feet away with copper tube to the shaft log. I've had lots of boats without a grease fitting on the stuffing box, too. For a long term keeper, I would add it.You have to use genuine water pump grease.Manny, when you replaced the packing in your stuffing box, did you cut single rings and butt the ends?Sometimes folks just wind the packing in a spiral by mistake. That will make it tighten and bind, causing heat.It's really hard to get your stuffing box adjusted so it will drip when running and stop when stopped. It will need to run a while and be tightened a few times before you can leave it alone, and even then it's unusual to have it stop dripping at rest unless you add the grease fitting.

 

[LancerDude]

Shaft Bearings..

..I have'nt had this problem on my boat but I used to build and Race cars...one "Toy" I had was high miles,it was a truck that had been run off road alot..but,to make a long story short..the rear seal on the trans and the front seal on the differential would both leak.I changed them several times but could'nt figure out why they kept wearing.Then I figured it out..the bearings in the differential on the input shaft were worn and letting the shaft move too much.Check your output shaft bearings..I'm betting you did'nt change these or,if you did,that there is wear on the shaft itself. Good Luck>>> Davd

 

[Manny]

Bearings

Fred, I cut the ends and butted them, at an angle per the tech at the shop were I bought the packing. Lancerdude, I actually replaced the output shaft bearing. I thought bearing wear may have contributed to the seal failure initially. One thing that I'm not sure about is after talking to a fellow boater on my dock, I may have put the seals on backwards, with the channels facing out. I don't think I did but I'll have to pull the trans and check.Thanks for all input,Manny