Lower unit oil leak - 35hp 3 cylinder

[Dustballs]

Saw some oil on the ground this morning. Looks like it’s coming from the area around the propeller. Can someone point me to where I should be looking into?

thanks.

 

[F_R]

That is the exhaust pipe. Unburned fuel and oil commonly drains out of it. BUT it is possible that it is gear oil. I'm betting not.
Remove the propeller and see if you can tell exactly where it is coming from. If coming out around the prop shaft seal, there is a problem. Otherwise, relax and don't worry about it-----After you check the gear oil for level and possible water intrusion.

 

[boobie]

Do a pressure and vacuum test on it. Takes the guess work out of it.

 

[Dustballs]

Do a pressure and vacuum test on it. Takes the guess work out of it.

Just did a pressure test test and it’s losing pressure. That means I need to replace all the seals?

 

[boobie]

Try some soapy water and find out where it's leaking !!

 

[oldboat1]

+1 ^^. Alternatively, dunk the l.u. when pressure testing and look for bubbles.

 

[Dustballs]

This is becoming a horrible experience. 3 of the 6 bolts holding the LU to the exhaust housing is over tighten and rounded. I’ve tried using a bolt extractor and it’s not working. I’m running out of options. Any suggestions?

 

[oldboat1]

Salt water motor? (didn't see a location for you). Heat and a pair of vise grips, maybe. Start with a dose of lube (ATF and acetone, possibly).

 

[Dustballs]

Salt water motor? (didn't see a location for you). Heat and a pair of vise grips, maybe. Start with a dose of lube (ATF and acetone, possibly).

I’m in FL. Boat is new to me and previous owner had it in salt water.

Wont the heat melt the LU casing? Space is tight so I can’t get a vise grip in there.

 

[oldboat1]

Not from the typical shop torch.

You might be at a point where it would be good to reconsider a bit. Can try your pressure test again, and see if your technique might have been the issue. Might consider that a winter project -- continue boating, maybe changing out the oil now and then. I gather it isn't entirely clear yet that it's gear oil you are seeing (Does it smell like gear oil, btw? Strong sulphur smell?)

(ed. Although I guess "winter project" means something different down there. I'm in upstate NY....)

 

[Dustballs]

I cleaned up the oil off the ground since I decided to remove the LU. When I drained the gear oil there wasn’t much in there which leads me to believe that’s what I was seeing.

I found a thread where someone ended up cutting off the head of the bolt. I think that may be my next option, tho I’m not sure how to accomplish that since the bolt is flush with the casing.

The obly torch I have is the blue torch they sell at Home Depot. Is that what the shop torch is?

Not from the typical shop torch.

You might be at a point where it would be good to reconsider a bit. Can try your pressure test again, and see if your technique might have been the issue. Might consider that a winter project -- continue boating, maybe changing out the oil now and then. I gather it isn't entirely clear yet that it's gear oil you are seeing (Does it smell like gear oil, btw? Strong sulphur smell?)

(ed. Although I guess "winter project" means something different down there. I'm in upstate NY....)

 

[oldboat1]

Yeah, that's the typical torch. Sometimes might not be hot enough, but good to try that first.

You may not need to remove the lower to check or replace the prop seal.

 

[Dustballs]

I heated it up for a few minutes but with the rounded head I don’t get a grip to turn it.

 

[Dustballs]

Getting a different set of bolt extractors and will try again tmr.

 

[Dustballs]

Still no luck. Where should I apply heat? To the head of the bolt? Or to the mid section of the motor where the bolts screw in?

 

[Vandkanten]

If you have space enough you can drill out the bolts. It is not that difficult.

 

[racerone]

Heat the casting where the bolt threads in.-----A wee grinder can cut the heads off.-----Factory bolts are big $ , but there are options.

 

[oldboat1]

With a cutting disc on that wee grinder, you might also be able to cut a slot, and back it out with a bladed screwdriver. Depends on what room there is to work with.

 

[Dustballs]

Are you calling a dremel a wee grinder?

 

[oldboat1]

I would (a wee cutter wheel, at least).