Re: [Amel] Re: Bowthruster oil - how to oil top up? - quick question

Danny and Yvonne SIMMS

Hi Colin, yes I had the same problem, identified before the boat went back in the water three years ago. I applied a fix I used with some agricultural machinery with great success over many years. Mix the oil 50/50 with a compatable grease, end of problem. It is lubricating the bevel gears at the bottom so they are well coated and when it is in use warmth from the action softens the grease/oil mixture and ensures good lubrication. I just changed the oil a month ago, all there and no water in it.
While I am on the topic of grease. Some time ago I posted about fitting grease nipples to the outhaul and furler gearboxes. Just openned one up to see how it was. Full of wonderfully clean grease in good condition.  
SM299 Ocean Pearl
New Zealand

From: Colin Streeter <>
Sent: Friday, 4 May 2012 8:18 PM
Subject: Re: [Amel] Re: Bowthruster oil - how to oil top up? - quick question

Dear friends

Many thanks for all the advice. Yes, Island Pearl II is on the hard stand
having her anti-foul painting done so we used this opportunity to service
the bowthruster. We dropped the thruster unit out after the recent advice
as we discovered that this is a relatively easy process to do on the hard.

Unfortunately after changing the oil seal behind the bowthruster propeller
we found oil oozing out of the centre edge of new Amel supplied rubber seal
where it spins around the little plastic bearing shaft. We changed the
bearing rubber seal twice today, (a new one each time) and re-filled the
oil each time but unfortunately the leak remained. On the first attempt we
put the rubber seal in with the opening side with small stainless steel
spring facing outwards. Since this did not work we cleaned it all down
again and put the rubber seal in the other way around with the spring and
opening side facing inwards. Unfortunately the SAE90 gear oil continued to
ooze out the area in the centre where the rubber seals turn around the
plastic propeller shaft.

I now suspect that the problem could be that the little plastic shaft which
turns the prop could have a small amount of pitting in it, or scratches,
which results in small amounts of oil coming out as the shaft turns?

My 3 questions therefore are:
1) Has anyone else had such a problem, ie. oil leaks from the bottom
bearing after renewing the rubber seal? If so, how did you fix it?
2) Is it normal for a small amount of oil to ooze out of this bottom
bearing? - and if so does it stop leaking when underwater due to a
balancing force on it from the water?
3) Should the rubber seal go on with opening and spring facing inwards or

Many thanks

Colin Streeter
Island Pearl II - SM2k #332

On Fri, May 4, 2012 at 4:03 AM, Ian & Judy Jenkins <> wrote:


Hi Craig, That's an interesting solution which I hadn't thought about. The
reason why it is of interest to me now is that I changed the oil in my B/T
about a month ago and put in the 0.3 litre ( 9 oz or 0.32 US quarts )
recommended by Gary Silver in his note of 5th Jan 2007, but I subsequently
found an original Amel document suggesting 3/4 of a litre.
Gary, if you happen to read this one, do you know the answer to the
discrepancy ( and is it critical ?).
Cheers, Ian and Judy, Pen Azen, SM 302 St Raphael

Date: Thu, 3 May 2012 17:19:20 +0000
Subject: [Amel] Re: Bowthruster oil - how to oil top up? - quick question

It sounds as though you are "on-the-hard" (unless you changed the prop
and oil seal underwater), hence I'd recommend you simply drop the unit,
turn it over to drain the old oil, refill and reinstall. Since you've just
done that a few months ago, I should think you wouldn't have to "fight" any
corrosion that would make removal difficult. Plus, since you've had an oil
leak it's likely the old oil is contaminated with water and should be

If, however, you're set on refilling with it in place, I suppose you
could try to do so by removing just one of the bolts holding the support
tube and insert a small tube through the bolt hole and introduce the oil
that way. I've got an outboard motor lower unit gear oil hand pump with a
long tube that could work, although I've not tried it myself. Inexpensive
at any Chandlery. You'd probably want to remove a second bolt so you can
see when the oil comes up to the top.

And, yes, the oil simply goes in adjacent to the drive shaft and fills
up the supporting tube.

Let us know if this works and if it's easier than just dropping the unit.

Craig Briggs, SN#68 "SANGARIS" in Leros, GR

--- In, "islandpearl2_sm2k332"
<colin.d.streeter@...> wrote:
..... My question is how (& where)to re-fill the bowthruster gear oil
quickly without removing entire unit? I have looked at the information on
the site but it does not tell one where to pour the new gear oil in. My
assumption then is to simply pour 0.3 litres of the correct oil into the
top of the shaft. Is this correct? Also can I do this somehow without
removing the top motor and dropping the shaft?


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