Perishing plastic oil dipsticks for Yanmar / Kanzaki transmissions

[MattS]

Just a bit of a friendly warning (and also so that there's a recent forum thread for others looking for help with this as I was recently).

TL;DR

• If you have a Yanmar / Kanzaki gearbox with a plastic oil dipstick, the plastic is vulnerable to perishing/going soft and breaking off in the gearbox.
• If you have a Kanzaki gearbox, they are marketed under Yanmar name in the UK at least, and so you're better off looking for Yanmar parts. My Kanzaki TTMC35A2 is Yanmar KM35A2 for instance.
• Yanmar manufacturer replacements are still plastic and are expensive, but you can get anodised aluminium replacements from Cariblue Marine for less than the price of 2 of the original plastic ones. This is what I'm now doing for peace of mind.

The Problem in more detail...

I have a Kanzaki TTMC35A2 gearbox fitted on a Beta 20 engine.

On doing a routine check of the gearbox oil, the plastic dipstick thread just sheered off the cap and got stuck in the gearbox. I hadn't applied any real force, the plastic had basically gone completely soft.



At first, it was near on impossible to find any replacement parts for my Kanzaki gearbox, no one wanted to know including Beta. It turns out that Kanzaki gearboxes are re-branded as Yanmar in the UK, and so the equivalent Yanmar gearbox model number was KM35A2.

It also turned out that this perishing plastic dipstick issue is quite common, and there are lots of reports of it happening (including from one of my sailing friends who also has a Beta).

I struggled to find a replacement dipstick part, but eventually found a Yanmar replacement that looked like it would fit at £55. On arrival, it is indeed the right thread and cap, but the dipstick is too short to reach the oil - so is clearly for a different gearbox model.

This is the one I bought: Yanmar 177088-02451 Dipstick - French Marine Motors Ltd

This is the part I should have ordered for the KM35A / KM4A I think: Yanmar 177070-02450 Dipstick - French Marine Motors Ltd

Out of frustration with having to pay £55 for a part that was known to fail regularly (plastic oil dipstick that is destroyed by oil?!), I did more furious forum browsing and found a thread from 2012 pointing to Cariblue Marine who are manufacturing anodised aluminium replacements for precisely this reason. You can get a complete dipstick or just the cap into which you can fit the original Yanmar metal dipstick. I'll probably just get a complete new one for the $10 difference in cost.

 

[vyv_cox]

You are correct, how a manufacturer could make a dipstick from a plastic that cannot resist warm oil is difficult to understand.

After mine broke off just as in your photo I extracted the piece in the box with a file tang and reattached it with two self-tapping screws. It has been OK for years now.

 

[MattS]

You are correct, how a manufacturer could make a dipstick from a plastic that cannot resist warm oil is difficult to understand.

After mine broke off just as in your photo I extracted the piece in the box with a file tang and reattached it with two self-tapping screws. It has been OK for years now.

The plastic on mine is so soft I just wouldn't trust any kind of working fix on it. My concern would be the plastic lugs failing that hold the metal dipstick in, and the dipstick falling straight into the gearbox! As with so many things boat, it's always a toss up between spending a load of money in the hope that it will save you money in the future, or drawing the line and making good isn't it! People who've gone with the aluminium replacement seem to have been pleased with it, so I'm going to take a punt!

And then see if I can sell my barely used new Yanmar oil dipstick to someone...!

 

[tjbrace]

Mine broke the same. Had replacement made by local engineer. He used an old spark plug to match the thread size

 

[JH77]

Just a bit of a friendly warning (and also so that there's a recent forum thread for others looking for help with this as I was recently).

TL;DR

• If you have a Yanmar / Kanzaki gearbox with a plastic oil dipstick, the plastic is vulnerable to perishing/going soft and breaking off in the gearbox.
• If you have a Kanzaki gearbox, they are marketed under Yanmar name in the UK at least, and so you're better off looking for Yanmar parts. My Kanzaki TTMC35A2 is Yanmar KM35A2 for instance.
• Yanmar manufacturer replacements are still plastic and are expensive, but you can get anodised aluminium replacements from Cariblue Marine for less than the price of 2 of the original plastic ones. This is what I'm now doing for peace of mind.

The Problem in more detail...

I have a Kanzaki TTMC35A2 gearbox fitted on a Beta 20 engine.

On doing a routine check of the gearbox oil, the plastic dipstick thread just sheered off the cap and got stuck in the gearbox. I hadn't applied any real force, the plastic had basically gone completely soft.

View attachment 141641 View attachment 141642 View attachment 141643 View attachment 141644

At first, it was near on impossible to find any replacement parts for my Kanzaki gearbox, no one wanted to know including Beta. It turns out that Kanzaki gearboxes are re-branded as Yanmar in the UK, and so the equivalent Yanmar gearbox model number was KM35A2.

It also turned out that this perishing plastic dipstick issue is quite common, and there are lots of reports of it happening (including from one of my sailing friends who also has a Beta).

I struggled to find a replacement dipstick part, but eventually found a Yanmar replacement that looked like it would fit at £55. On arrival, it is indeed the right thread and cap, but the dipstick is too short to reach the oil - so is clearly for a different gearbox model.

This is the one I bought: Yanmar 177088-02451 Dipstick - French Marine Motors Ltd

This is the part I should have ordered for the KM35A / KM4A I think: Yanmar 177070-02450 Dipstick - French Marine Motors Ltd

Out of frustration with having to pay £55 for a part that was known to fail regularly (plastic oil dipstick that is destroyed by oil?!), I did more furious forum browsing and found a thread from 2012 pointing to Cariblue Marine who are manufacturing anodised aluminium replacements for precisely this reason. You can get a complete dipstick or just the cap into which you can fit the original Yanmar metal dipstick. I'll probably just get a complete new one for the $10 difference in cost.

Did you end up purchasing the dipstick from Cariblue Marine? I reached out to them but their correspondence leaves me wondering about their legitimacy.

Thanks!

 

[Sailing steve]

You are correct, how a manufacturer could make a dipstick from a plastic that cannot resist warm oil is difficult to understand.

It becomes far easier to understand why any manufacturer would do so when you consider that rather than providing a satisfactory quality product for the consumer companies now prioritise extracting as much money as they can out of customers who are tied into their products to the benefit of their shareholders and franchisees.

Sub standard components represent a triumph of accountants over engineers and invariably the end user pays the price.

 

[MattS]

Did you end up purchasing the dipstick from Cariblue Marine? I reached out to them but their correspondence leaves me wondering about their legitimacy.

Thanks!

I did - I received the dipstick and it seemed very nicely made.

 

[Cerebus]

What a remarkably rubbish piece of engineering.