oil from an odd spot on lower unit?

[woodsman]

Hey guys, I will have some pics up as soon as I can, but I wanted to go ahead see if I could get some input. I fished out my xtb quit a bit the last week. Going out about 6 different times and having some fun while doing it of course. After parking it up in the garage and it sitting over night being out of the water for two days I notice a oil spot the size of an apple on my floor. Thinking straight away that I had prop seal failure, I looked and it is good. I then thought drain plug o-ring failed. It wasn't coming from there either. I then looked and it was coming from a small hole the size of a pencil eraser between the water fittings for the nose cone. have no idea where this oil could be coming from. Is this an issue?

 

[Darth VMAX]

Are you sure its not coming from something above it and its just dropping on that spot making it appear thats the source?

Do you have a hyd jackplate? Could be coming from there.

 

[msethsmile]

I had a buddy that the casting cracked on a sportmaster in the nosecone. Oil leaked out the cone. The point is cracks can occur in weird places.

 

[woodsman]

Wow! Thanks for the very quick replys. Although I wished I did, I do not have a hydraulic jack plate it is manual. And the oil is coming from a cast hole in the original part of the lower, so it doesn't seem to be a crack. I took some pics so you can see what I see.

 

[woodsman]

 

[woodsman]

 

[ssv1761982]

Wouldn't that be the shift shaft seal? Leaks and dribbles out the weep hole. Too much lower unit lube then a long high speed run will heat the lube and force it out there.

Just a guess.

 

[woodsman]

It is the hole that is in the shift shaft cavity at the top of the casing. I didn't put those things together but I see what you are saying. I have ran it a lot and I am sure that I got the lower good and warm. So would this mean my shift shaft seal would be bad? Or would this mean that a little to much oil is present in my lower and seal reset?

 

[SLOmofo]

Shift shaft seal as said. Check condition of fluid, could have water in it causing this condition. From what I understand(which is little) the shift shaft seal is used as an over pressure vent, instead of all seals being positive this one leaks first.

 

[woodsman]

I see, easily understood when looking at it that way. I do know the way the seal is made it would allow vent much easier.
I checked the oil and it is top notch. Must have overfilled a little maybe. It is about due to be changed again anyways so I will probably just change it. But it was colored about like motor oil for the world, darker oil that it. More black than anything.

 

[allimax]

Shift shaft seal as said. Check condition of fluid, could have water in it causing this condition.

Gotta agree. Every year when I change the fluid out I clean my light grey drain pan out real good & drain into it so I can check for a milky condition to the fluid. So far so good for me. The sportmasters come with a hardened steel drive shaft and they are notorious for rusting below the water pump and causing a leak. The best tool you can own for diagnosing one of these is a vacuum / pressure pump. If you buy this tool thru a marine dealer you'll be close to 2 bills. Buy it here, well worth the investment.
http://www.tooltopia.com/mityvac-mv8500.aspx
Now you can adapt a lower unit fill tube to your hand pump and test for any leaks. You want to put about 10" Hg of vacuum on it and see if it holds, say for 10 minuets, then do the same thing with 10psi of pressure. If she's leaking with pressure some soapy water in a spray bottle is real handy.

 

[allimax]

Oh, and the rule of thumb is after you have it full of new fluid, drain about an extra shot glass back out before you put the fill plug in. This will help allow for the expansion the fluid needs when it gets hot.

 

[dragmerc]

mercury recommends draining extra oil from completely full in gearcases that are going to be run surfaced. they said heat causes oil expansion and pushes seals out. i saw it twice where prop seals were pushed out. drained 3 oz below full and no more problem.

 

[woodsman]

Thanks so much for the info and tool references. Allimax you have been very informative and I appreciate that. I must say it is my fault. I changed the fluid last and I did not drain the extra couple ounces/shot glass worth back out of a full case. So, I am sure now that I over filled it.
Checked the oil in the lower and it is good to go. No water seems to be in it, but I will be keeping an eye on it the next couple trips out. And I will be getting me a vac/pressure gauge for sure. Thanks again guys.

 

[allimax]

FYI, Dragmerc had a much clearer explanation. Testing the lower and closely inspecting the fluid each year should be standard procedure. Catch a problem early and it's way cheaper on your wallet. The typical shot glass holds 1.5 ounces so that would be X2. Honey Turkey is really good!

 

[brotherxb03]

My brother has a outboard shop and I think he told me about a vent kit for a sportsmaster that vents up to the cowl, I"d guess where the speedo hose passes. Those prop shafts are a piece of crap on the sportsmaster and don't last for what they cost they should be bullet proof.I'm talking about the seal area rusting. As far as the drive shaft u can machine a s/s one to accept both bearings, I know my brother does it.

 

[allimax]

Correct me if someone knows I'm wrong but I think the reason for using a hardened steel drive-shaft and not stainless is because it is stronger and has a better chance of surviving the torque of a hi performance drag motor. After a weekend of use the drag guys will have everything pulled all apart so no big deal. I've been pulling my lower every year, testing it and keeping the problem areas tended to with Gibbs (use what you want to displace the water, LPS, WD-40 etc.) Once mine goes I'll take the advice of one of the experts on here and let someone who really knows them do it. Redi-Sleeve, spray welding, replacement stainless shaft are all options, I don't know which one is best.:argue

 

[SLOmofo]

--------------------------------------------------------------------------------

"Correct me if someone knows I'm wrong but I think the reason for using a hardened steel drive-shaft and not stainless is because it is stronger and has a better chance of surviving the torque of a hi performance drag motor."

That's what I would think also!

"Gibbs"

Good stuff!

 

[brotherxb03]

you are correct, but some people run these lower units on lower Horse Power fishing motors that don't need the harder shafts, but want something that last longer without the seal area failing from corrosion.

 

[allimax]

"Gibbs"

Good stuff!

Yep, didn't see that one coming. I suspect maybe one other out there that's heard of Gibbs. PB Blaster fan...........hah! What a minute, you have no rust in southern California????