Saltwater in lower unit fluid Flushing Question

[mlagrassa]

I have a 1987 DP-A2 that one of the seals leaked causing saltwater to mix with the gear fluid. I've fixed the seal but want to know what is the best way to flush out the outdrive to get rid of any water or salt residue. I've heard that using deisel fuel would work, but I'm sceptical.

Any advice on flushing the outdrive?

 

[wrench 3]

Re: Saltwater in lower unit fluid Flushing Question

The only safe thing I know to flush a gear box with is a light weight oil. Diesel fuel is a very light oil but I would prefer a 10 weight.
Next time get a complete reseal kit and clean things out while it's apart.

 

[K-2]

Re: Saltwater in lower unit fluid Flushing Question

Last time I got water in mine the oil got very thick and sticky.
I flushed it a couple times with straight diesel, then went to hydraulic oil , a couple flushes with that then
engine oil, 15-40 or something then let that drain overnight and then used Volvo synthetic gear oil.
If it is just a little water in the oil and it drains quickly like straight oil would, then I just let it drain for as long as possible, overnight is good, then put in new gear oil, no flushing. I put at least 500 hours a season on my outdrives,,,,water in the oil is not uncommon , I always pressure test before I repair anything , to make sure I am replacing the correct parts, it's usually the shaft seals and once in a while the u joint drive shaft bellows. Once it was actually a cracked top cover.

 

[jerryjerry05]

Re: Saltwater in lower unit fluid Flushing Question

Lots of reasons for a leak.
The one I found the most was the shift arm under the cover??
Yes diesel is good.
The older drives required 30wt for lube.
After the first trip change it again.

It's amazing what you find if you look, I was researching parts for a different job.
It seems Volvo even makes a thru hull exhaust and a water heater for the boat,COOL!( I mean hot)

 

[Scott Danforth]

Re: Saltwater in lower unit fluid Flushing Question

Diesel is good.

on the VP's also look at the input seal on the upper gear box. if your bellows leaked a bit, the u-joints will be rusty and will have eaten your input shaft seal. Also agree with Jerry on the shift arm seal.

 

[billbayliner]

Re: Saltwater in lower unit fluid Flushing Question

I agree also. Shift seal is the seal I see damaged the most. Seems that the cover holds in growth and debris (mud, sand) and it helps deteriorate the seal.

Also, noticed you say the model is a 1987 DP-A2. Was this a replacement drive as the DP-A2 model was not out till a couple years later. They were still using the 290 drives in that year.

Also, the DP calls for only FULLY synthetic GL6 rated gear oil.

Personally what I would do is pull the lower bearing carrier out and be on the safe side and kill 2 birds. Change the lower bearing carrier seals and clean out the lower.

I have a thread some where on here a few years back showing a home made unit that works better than Volvo's specialty puller. Should be able to do a search and find it.