Caution Yanmar and other engine owners

[Coppershield]

Fellow boat owners,
for a number of years I wanted to post a caution regarding Yanmar engine oil leaks from bonjo connectors. I'm not sure if the bonjo is the right term nor the right spelling, it is the one were the bolt which is hollow and goes true O shaped connector that makes up the right angle connection. After reading the post from "ShipWoofy" on another post it reminded me to make this post.
This is a caution on an engine otherwise it is excellent product. Just over three years ago engine started leaking oil suddenly and it could not be stopped with tightening of the bolt, I was lucky this happened in port.


If You have this kind of connectors You may want to have some spares on hand.
And if your engine is reasonably new, You may consider doing something about it so this will not happen to You in the wrong place and the wrong time. There are number of ways to remedy this but perhaps the easiest will be to smear wheel bearing grease were the copper washers meeting the other material. Combined with moist environment causing the galvanic activity and rusting the mating surfaces in turn expanded rust makes it nearly impossible to seal it.
Without resurfacing the mating parts, I am sure once You know the problem exists, You will come up with contingency plans.
Best regards /forums/images/graemlins/smile.gif
Muzaffer

 

[Porthandbuoy]

I always thought they were called "banjo" connections. Still, nipping them up is only a temporary solution. ALWAYS fit a new copper washer if the seal is suspect or if it is ever dismantled. When new the copper washer is annealed and lovely and soft. Once it's been tightened it becomes work hardened and cannot be relied upon a second time.

 

[Coppershield]

A very good point

Hi Andy,
that is a very good point, so the spares should be carried on board or if I remember correctly, they should be heated close to 500° F. and then let it cool at room temperature if the spares are not available.
With my original post I just wanted to warn the new boaters of this problem even with the new washers the need of resurfacing the banjo faces.
Thank You /forums/images/graemlins/smile.gif
Muzaffer

 

[jerryat]

Re: A very good point

Oh Lord! I thought annealing meant heating the copper washer to 'cherry' red, then dousing immediately in cold water. It's what I've done a couple of times when caught short for a washer when cruising and not had a problem - perhaps you can do it both ways!

 

[bonny]

Re: A very good point

Cherry red & cold water (or was is copper sulphate) is what I remember from my metalwork days in school 30 odd years ago!

 

[Porthandbuoy]

Re: A very good point

You can re-anneal a copper washer in an emergency; but remember, it will be thinner than a new one!
Bye the way, don't use bonded seals (a steel washer with an elastomer insert), they are not as good at resisting vibration and are prone to coming spontaneously undone.

 

[Coppershield]

You are right

Hi Jerryat,
You are right, copper can be annealed both ways. Your way will be preferable because it would minimize surface oxidation.
In my previous post I mistakenly put 500° F. instead of 500° C.
annealing temperature for copper is around about 450° C. and up to about 800° C.
thanks /forums/images/graemlins/smile.gif
Muzaffer

 

[snowleopard]

Re: A very good point

[ QUOTE ]
they should be heated close to 500° F. and then let it cool at room temperature

[/ QUOTE ]
steel is annealed by allowing to cool naturally and hardened by quenching. copper is the reverse. i've no idea why.