Exhaust system Yanmar (Spare Parts) - Yanmar Exhaust Elbows, Exhaust Turbo Gaskets

The exhaust system of your Yanmar marine diesel technically starts from the moment the fuel is burnt in the chamber and the exhaust gases are being released from the exhaust valve. As soon as the hot gases leave the combustion chamber, they pass through the exhaust manifold. In between the exhaust manifold and your cylinder head, an exhaust manifold gasket acts as a sealant. It is of crucial importance to guarantee that both surfaces are clean and even before the installation of the gasket; otherwise, there might be exhaust fumes leaking. If your engine is naturally aspirated, the next component will be the exhaust elbow/exhaust pipe, while a turbocharged engine will have the turbo mounted onto the exhaust manifold.

The turbocharged engines are using a steel gasket between the exhaust manifold and the turbocharger, while a v-band clamp connects the exhaust elbow to the turbocharger in order to redirect the gases towards the downpipe. The connection between your Yanmar turbocharger and the exhaust elbow is usually bare metal, which means you have to make sure again that the surfaces are clear. It is common sense that a problem in your turbocharger will directly affect the exhaust system and the overall performance of your engine; however, we will dedicate more time to your Yanmar turbocharger later in this article. Your Yanmar elbow is connected to your exhaust manifold, and a gasket is placed between those two parts. The majority of the exhaust elbows for Yanmar offered by Recmar are stainless steel, with the exception of the Yanmar 2GM series and Yanmar 3GM series elbow/riser with part number 104070-13520, which is made of mild steel.

So, the long debate: “New exhaust elbow - Cast iron or Stainless steel?”

If we had to answer your question in one sentence, we would say that “Your Yanmar exhaust elbow would be better made of stainless steel, since it will last longer and, technically, does not require maintenance.” In depth, a stainless steel exhaust elbow will have much less carbon deposition, a common reason for the clogging of a mild steel elbow. The clogging in turn increases the corrosion’s speed, which is accelerated even more when the environment is hot and salty. Wasn’t that the environment of most seawater basins? Correct. Another critical element of the exhaust elbows is the technique of casting. A welded elbow has weak spots that will break due to thermal fatigue. However, all Recmar’s stainless steel elbows for Yanmar are made of investment casting (lost wax) using 316 stainless steel. Investment casting means that there are no weldings, so no weak spots. After the casting, the elbow is being machined to flatten the mating surfaces (this procedure gives some slight magnetic properties) and then is galvanized for further protection. Summarized, the most eminent benefits of a stainless steel elbow are:

i) Less carbon deposition, less clogging over time.

ii) Longevity—higher value for money, quality made affordable.

iii) No chance of thermal fatigue.

So, what does a mixing elbow do?

The mixing elbow is doing exactly what its name suggests, it mixes the hot exhaust gases with cool water, in order to lower the temperature and reduce the noise levels.

The mixing elbow, or exhaust elbow, it is the same thing, is a consumable, which will need some time replacement. How long will an exhaust elbow last? This is a multifactor answer that depends on the composition of the water you are cruising, how meticulous is done your annual maintenance, what is the condition of your fuel system, your intake system and the rest of its peripheral exhaust components. Lastly, but maybe the most important fact: the material of the elbow and if the elbow is equipped with a sacrificial anode. If you need to orient yourself, a properly maintained cast iron elbow may last more than 8 years on a leisure use, while there are examples that exceed ten. 

A cast iron elbow will have signs that will ring a bell to you to replace it. How to tell if the risers are bad? How do I know my exhaust is bad? Both questions are a matter of observation of your current exhaust system. If the thickness of your elbow’s walls are reduced significantly, or if your elbow has started falling apart near the outlet, it is a clear sign that you need to change it. If you are not sure, a light acid bath will show the condition of your elbow. Alternatively, you can do a sandblasting, provided you will not use a very aggressive blasting material. That way, small cracks or under-paint corrosion will show up.

It is time to replace your exhaust elbow and you are presented with two options: an expensive genuine cast iron elbow and a more affordable, upgraded, lost wax cast stainless steel. What is your choice? Well it is obvious, isn’t it? But, how long does a stainless steel exhaust last? To be 100% honest, the last 10 years, we had few choices of stainless steel elbows, and most of them were made of welded stainless steel, which is prone to thermal fatigue. On the other hand, we have been offering Recmar’s cast investment elbows for at least three years, with zero defects, zero complaints and we estimate that they will technically last a lifetime.

Our extensive inventory will cover your needs, weather you are looking for an elbow for a compact Yanmar engine like 1GM, 2GM, 3GM, 2YM, 3YM series or a larger 3JH, 4JH, 4LH, 6LP or 6LY series.

Coming back to the previous topic, concerning the Yanmar turbochargers and “How to take care of a turbocharger for your Yanmar marine engine”?

As per the operator’s manual of the Yanmar 6LP engine series, a turbocharger will need a cleaning every 150 hours of use or whenever there is a 10% or more reduction in the boost pressure. However, you can achieve similar or better results by just cleaning the aftercooler. As per the experience of many boat owners, the maintenance of the turbocharger should be better left to turbo specialists instead of doing a mounted cleaning since this technique can be potentially dangerous. Generally, the health of your turbocharger is a multifactor issue, tightly related to the fuel system and the lubrication system. A bad injector for example, might be responsible for black smoke, which causes over time carbon deposits on the turbo wheel. Problems with the intercooler can also reduce the lifespan of your turbo. Even worse, a damaged air filter can have small parts sucked into your turbo, ruining it completely. Leakage between the piping or poor lubrication can also be factors that may lead to premature wear of your Yanmar turbo. In our store, you can find a wide range of good quality replacement turbochargers, made by Recmar. Additionally, you can also find turbo to manifold installation gaskets and other turbo-related products.

Popular products (elbows):

Recmar® Stainless steel Exhaust Elbow Yanmar 2YM15 3YM20 3YM30 128890-13530

Recmar® Stainless steel Exhaust Elbow Yanmar 4JH 129792-13552 129671-13551

Recmar® Stainless steel Exhaust Elbow Yanmar 4LHA 6LP 119773-13501

Recmar® Stainless steel Exhaust Elbow Yanmar 3GM30 3HM35 128370-13550