Lower Unit Oil Leaking into Bilge

[baccus06]

I have a 1996 StarCraft 2010 with the 5.7L Mercruiser/Alpha One drive. I was investigating a lower unit leak this weekend and can't find the exact spot where it is leaking. I followed the line from the reservoir to the transom fitting and found no signs of leaking. It appears that the oil is leaking below the through hull fitting. I have not pulled the drive yet (no experience with this) and wanted to see if anyone else has had this problem? I purchased the boat last June, and in late August I discovered the leak. The previous owner had the gimbel bearing and u-joints replaced the previous fall. I have been looking for as much information on the what to do as I can find, but haven't been able to find a similar situation. I am more than capable of doing the work but I do not want to dive in with out a basic plan of attack first. Does anyone have any suggestions on where the leak may be coming from? I believe the through hull fitting is the brass fitting and not plastic but I'm not positive. Any thoughts or direction to another post would be great. Thanks

 

[Bondo]

Re: Lower Unit Oil Leaking into Bilge

I have a 1996 StarCraft 2010 with the 5.7L Mercruiser/Alpha One drive. I was investigating a lower unit leak this weekend and can't find the exact spot where it is leaking. I followed the line from the reservoir to the transom fitting and found no signs of leaking. It appears that the oil is leaking below the through hull fitting. I have not pulled the drive yet (no experience with this) and wanted to see if anyone else has had this problem? I purchased the boat last June, and in late August I discovered the leak. The previous owner had the gimbel bearing and u-joints replaced the previous fall. I have been looking for as much information on the what to do as I can find, but haven't been able to find a similar situation. I am more than capable of doing the work but I do not want to dive in with out a basic plan of attack first. Does anyone have any suggestions on where the leak may be coming from? I believe the through hull fitting is the brass fitting and not plastic but I'm not positive. Any thoughts or direction to another post would be great. Thanks

Ayuh,.... Welcome Aboard,.... Pull the drive,....

If the bellows is fulla oil, the big seal at the input shaft is leakin' from the drive,...

 

[MarkSee]

Re: Lower Unit Oil Leaking into Bilge

I have been looking for as much information on the what to do as I can find, but haven't been able to find a similar situation. I am more than capable of doing the work but I do not want to dive in with out a basic plan of attack first. Does anyone have any suggestions on where the leak may be coming from? I believe the through hull fitting is the brass fitting and not plastic but I'm not positive. Any thoughts or direction to another post would be great. Thanks

As Bondo indicated, you have to pull the drive and verify if you indeed have gear oil in the bellows and THEN you can formulate a plan.

But there are several threads here on IBOATS with similar situations so look near the top of the page and see the "advanced search" option, select that then in the 'keyword (s)' box, enter this: gear oil leak bellows
then click on the 'search now' selection and you'll find threads to read.

Also, the thru-hull fitting you are referencing, is that the 'drain plug' you remove after boating?
That would also be referred to as the 'garboard'.
Mark

 

[baccus06]

Re: Lower Unit Oil Leaking into Bilge

Thanks for the searching tip. I wasn't using the right phrasing. The fitting I am talking about for my gear oil monitor that goes from the hose to the lower unit. I haven't pulled the outdrive yet (due to lack of time) but with the new info I have found, I agree that it is probably the input shaft seal. I can't seam to find a write up on replacing that. Can you direct me to the manuals that are on here. It seems I've lost the ability to find anything I'm looking for. Thanks

 

[Bondo]

Re: Lower Unit Oil Leaking into Bilge

Thanks for the searching tip. I wasn't using the right phrasing. The fitting I am talking about for my gear oil monitor that goes from the hose to the lower unit. I haven't pulled the outdrive yet (due to lack of time) but with the new info I have found, I agree that it is probably the input shaft seal. I can't seam to find a write up on replacing that. Can you direct me to the manuals that are on here. It seems I've lost the ability to find anything I'm looking for. Thanks

Ayuh,.... Welcome Aboard,.... Right at the Top of this forum,....

Don'S Adults Only section,...

 

[baccus06]

Re: Lower Unit Oil Leaking into Bilge

Thanks. Once I pull the drive and find out what's wrong I'll post again.

 

[baccus06]

Re: Lower Unit Oil Leaking into Bilge

Well I pulled the drive and the drive bellows were filled with oil. I haven't pressure tested yet but from everything I've read here, the input shaft seal is bad. Can anyone direct me to where in the manual I may find how to replace it and also any other places that may help in the replacement? What special tools are required for this type of repair?

 

[Bt Doctur]

Re: Lower Unit Oil Leaking into Bilge

Here you go http://www.boatfix.com/merc/Servmanl/14/14cover.pdf

 

[ktbarrentine]

Re: Lower Unit Oil Leaking into Bilge

BT...When I pull up your link, it only gives me pages one and two... I found this one gives me the whole manual (in a slightly different format...)

Boatinfo - Mercruiser Service Manual nr. 14 - 1991-Current - Sterndrives Alpha One Gen II</

KT

 

[Bt Doctur]

Re: Lower Unit Oil Leaking into Bilge

click the link, click the "sterndrive" box area, scroll down to page 4, click on the section you need.

 

[ktbarrentine]

Re: Lower Unit Oil Leaking into Bilge

click the link, click the "sterndrive" box area, scroll down to page 4, click on the section you need.

Did that... all it did was take me to page two. No other links or pages. maybe it depends on the browser (using chrome).

(edited)...yep...that was all it was... Works great in IExporer. Thanks!!! (word to those who also may have had problems)....

 

[Bt Doctur]

Re: Lower Unit Oil Leaking into Bilge

I had to delete Chrome on mine. Came with its own virus. Some say there are downloads that look just like Chrome.
If you ever see PUP .Original in a scan ,your infected.

 

[baccus06]

Re: Lower Unit Oil Leaking into Bilge

Took the drive in to have it serviced. Input shaft seal was bad. had them do the impeller since they had it and they also found my water tube (cant remember proper name) was melted so they replaced that. Only cost me $277. Could of been worse. Thanks for all the info.

 

[mikef624]

I have a similar problem that I need some expert advise on... I have a bilge full of gear oil. I have a 7.4l carbureted Mercruiser with a bravo II outdrive. The second day of use the gear oil alarm went off on start up. The reservoir was empty. Filled it, went out... next day empty. its all in the bilge. I have traced the hose from the reservoir to the transom and it is dry and oil free... so i think it is leaking on the outside of the transom... i'm assuming in the bellows. here is the question.... feel free to smack me in the head. Am I going to make things worse if I don't fix it right away... assuming the leak is internal and not getting to the water? smack away. Didn't get the boat in the water until middle of july and just paid for a slip for the rest of the season... I don't want to pull it now if i'm not doing additional damage, and will pull it and fix it in a few weeks.

 

[cowansauto]

Re: Lower Unit Oil Leaking into Bilge Took the drive in to have it serviced. Input shaft seal was bad. had them do the impeller since they had it and they also found my water tube (cant remember proper name) was melted so they replaced that. Only cost me $277. Could of been worse. Thanks for all the info.

Are you talking about the oil seal that goes in behind the gimbal bearing? Is that what they replaced?

 

[baccus06]

The input shaft seal is in the lower unit behind the drive shaft on an alpha1. I didn't have the tools to replace it because of how it is torqued.

mikef624- if you run the boat on low gear oil you can destroy your lower unit. I wouldn't run the boat if loosing all that oil in one day.