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

Danny and Yvonne SIMMS

Sounds good, I would go for a bit more grease in the mix.

From: Colin Streeter <>
Sent: Saturday, 5 May 2012 7:11 PM
Subject: Re: [Amel] Re: Bowthruster oil - how to oil top up? - quick question

Hi Danny

Thanks. I spent some time in an auto specialist shop today and got two
different brands of compatible grease & oils and a number of test tubes.
Before putting it in the bowthruster unit I am currently experimenting with
mixtures in test bowls looking at viscosity and mix. I will leave it for 12
hours to check how it settles and to ensure it does not separate before
deciding on putting it into the bowthruster unit. Given my leak was very
slight, the mixture I have ended up choosing is 1 large heaped tablespoon
on Nulon water resistent multi-purpose grease with 700ml of Nulon Marine
SAE 90 Gearbox oil hand mixed for over an hour until it is perfectly
blended in.  The resultant viscosity will run but at about 1/3 of the speed
of the plain SAE90 gear oil.

I have also today discovered that I had not pressed the new rubber oil seal
in all the way and so have now pressed this right in and will be testing
the unit again tonight with the correct SAE90 gear oil. Only if that fails
will I go to the mixed version, assuming it remains perfectly blended over
the next 12 hrs and still maintains the same 1/3 speed viscosity.

Kind regards,
Colin Streeter
Island Pearl II - SM2k #332


On Sat, May 5, 2012 at 3:51 PM, Danny and Yvonne SIMMS <>wrote:


Hi Colin, sorry it was three years ago so can't remember the exact grease.
However, avoid synthetics, go for a mineral grease to go with the mineral
oil.And mix it 50/50 by volume. Funny how things happen.. We had just bought
the boat and trying to do every thing right. Bought the new seals from the
bearing shop in Ft Lauderdale. Leaked. So tried another. Leaked. Boat
eating its head off with hardstand charges and we were days late already.
thought. Maybe the seals are wrong. So ordered some from Amel. Took
incredible time to get there, and it leaked. So went to my default setting.
Did what I knew worked from past experience...temporarily...what choice did
I have? but works so well, so why change.

Ocean Pearl
New Zealand. (heading for the Pacific Islands end of June)

From: Colin Streeter <>
Sent: Saturday, 5 May 2012 1:44 PM

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

Hi Danny
Thank you again for your advice. I have had a careful look with a spotlight
overnight and the shaft seems perfect so no point in dismantling all the
gears etc. Since it is only a very fine leak I will give your suggestion a
try over the weekend and see what happens. Any suggestion about what grease
would be most compatible with Valvoline SAE90 high performance gear
oil? Which grease did you use?
Colin Streeter
Island Pearl II - SM2k - # 332

On Sat, May 5, 2012 at 6:04 AM, Danny and Yvonne SIMMS <

Hi Colin, yes I had the same problem, identified before the boat went
in the water three years ago. I applied a fix I used with some
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
bottom so they are well coated and when it is in use warmth from the
softens the grease/oil mixture and ensures good lubrication. I just
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
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

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

Unfortunately after changing the oil seal behind the bowthruster
we found oil oozing out of the centre edge of new Amel supplied rubber
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
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
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
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.
reason why it is of interest to me now is that I changed the oil in my
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
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

It sounds as though you are "on-the-hard" (unless you changed the
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
done that a few months ago, I should think you wouldn't have to "fight"
corrosion that would make removal difficult. Plus, since you've had an
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
tube and insert a small tube through the bolt hole and introduce the
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.
at any Chandlery. You'd probably want to remove a second bolt so you
see when the oil comes up to the top.

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

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

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
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
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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