lower unit ? please respond

[Darryl34]

Hi,could somebody tell me how to keep water out of my gearcase,other than replacing the washers on the drain plugs,which I have done.Motor,1975 merc 115 inline 6.How else could water get in,or is this enough replacing the washers? Thanks

 

[JasonJ]

Re: lower unit ? please respond

Sounds like it needs a reseal job. Water can get in around the driveshaft, the propshaft, the shiftshaft, etc. It is not as bad as it sounds to do, but if you have no mechanical abilities and are unfamiliar with lower unit rebuilds, you may need to check into having someplace do it. I can tell you that a seal kit is dirt cheap, and a shop will require large cash to do it. Do you know anyone who could hook you up?

 

[Darryl34]

Re: lower unit ? please respond

thanks jason,I may or may not have someone to do it.Hopefully,the new washer will do it.The old ones did'nt look too good when removed.If it is still leaking after,I'll try to limp it through the rest of the season with very regular gear oil changes.Oh also,It appears that gear oil may have been seeping out between the leg and gear unit,at the joint,where the two bolt together.from the rear where the fin is.Or,it was just running out that direction from the plug not sealing

 

[KCLOST]

Re: lower unit ? please respond

You can do a pressure test (with the lower unit removed) to find out where the leak may be coming from... Only use low pressure..

 

[emckelvy]

Re: lower unit ? please respond

Very likely it's the driveshaft seals or the shift shaft seals leaking. If your oil turns milky within a few runs, it's most definitely the driveshaft seals. If it were the propshaft seals you'd see them leaking externally when the motor is tilted down.<br /><br />A shift shaft bushing will usually leak pretty freely when the motor is tilted up. This may be what you have seen leaking from between the L/U and the exhaust tower.<br /><br />When driveshaft seals are bad, the negative pressure under the water pump sucks the oil right out of the lower unit. The oil is displaced with water.<br /><br />If the driveshaft seal area is deteriorated, a speedi-sleeve repair assy can be pressed over the damaged area.<br /><br />If you have a later model with stainless driveshaft, you may only need new seals. Not much more of a job than replacing the impeller, once you've got it down that far there's not much more to take apart.<br /><br />HTH.......ed

 

[Darryl34]

Re: lower unit ? please respond

I had changed the washers on the drain and fill screws yesterday,changed gear oil,and cleaned everything up.Looking at it today,gear oil ozing out right above the trim tab,at the joint between the leg and lower unit,(gear case)would this be the shift shaft seal?? or ?????

 

[btatum]

Re: lower unit ? please respond

driveshaft seal is allowing water to enter the foot below the water pump. you will need to remove the foot, waterpump, and shaft to access the seal. if your going through this trouble you might as well replace all the seals.

 

[Hooty]

Re: lower unit ? please respond

What does the stuff it's leaking look like? Is it all black and nasty lookin' or iz it, for sure, the gear lube you're puttin' in?<br /><br />c/6<br />Hooty

 

[tmcalavy]

Re: lower unit ? please respond

And if you're unlucky, like me, it may be that your driveshaft is pitted...which will make it almost impossible to reseal. I had to have mine built up and milled back down to original diameter to get it smooth enough to reseal. My boat mech did a complete lower seal job and had a shop do the shaft for me...total cost was $150-$200. Money well spent.

 

[Darryl34]

Re: lower unit ? please respond

its definatley gear oil,fresh and clean,as I changed it yesterday.What would it cost me to get it(the seals)fixed?Is it possible to use it as is,with a gear oil change after every use?I would like to limp it through the rest of the season if possible?

 

[achris]

Re: lower unit ? please respond

Yeah, no worries, limp through the rest of the season, you only risk screwing up your gears and bearings, which will cost you a bucketload more than the seal job. <br /><br />Seriously, get it fixed pronto. There's only about 3-4 hours work in it. If you drop the boat off on a Monday you should have it back for the weekend (barring unforseens). <br /><br />Chris.........

 

[Chris1956]

Re: lower unit ? please respond

Aquastar, It sounds to me like your driveshaft seals are leaking. To replace these, remove the lower unit, remove the waterpump top cover and base unit. Check the driveshaft just above where it enters the lower unit for grooves. If it is smooth, buy a new waterpump base (it has new seals installed) and install it with new gaskets and oring.