About Poseidon Marine Parts
PoseidonMarine™ is a global distributor of spare parts for inboard, sterndrive, and outboard marine engines, as well as chandlery equipment, chemicals, additives, and other products related to the care of a yacht. Our name is highly esteemed in the marine business due to the wide variety of parts we offer for Volvo Penta, Yanmar, and MerCruiser engines. Besides the aforementioned inboard and sterndrives, we have a varied inventory of spare parts for Suzuki, Tohatsu, Mercury, Johnson & Evinrude, Yamaha, and other outboard engines. The basic search categories of each engine brand are organized in easy-to-search subcategories. The most important of them are: The cooling system, the exhaust system, the anodes, and all consumable parts.
Here is the “top 25” of our most popular products throughout all categories:
- PoseidonMarine® Inner Propeller seal Volvo Penta DP 851407 18-0558
- PoseidonMarine® Trim Cylinder Rebuild kit Volvo Penta cylinder 3860881 metric
- Recmar® Seal for Volvo Penta saildrive propeller shaft 3593663
- PoseidonMarine® Trim Cylinder Rebuild kit Volvo Penta DPH DPR 21840806 21840807
- Recmar® Exhaust Valve Yanmar 6LP 6LPA 119770-00490
- PoseidonMarine® Trim Cylinder Ram for Volvo Penta trim cylinder 3860881
- Inner propeller seal set for Volvo Penta Duo prop 853871 853807 853808
- PoseidonMarine® Trim ram rebuild kit Volvo Penta SX DP-SM OMC Cobra 3854247 3885196 3857470
- Recmar® Intake Valve Yanmar 6LP 6LPA 119770-00480
- Recmar® Stainless steel Exhaust Elbow Yanmar 4LHA 6LP 119773-13501
- SLP® Injector sleeve kit Volvo Penta D4 D6 889970 3583716
- Poseidon Marine® Fuel pump Volvo Penta MD1 MD2 MD3 MD7 MD11 MD17 2001 2002 2003 833323
- Crom® valve stem seal for Yanmar 6LP 24-valve 119771-90210 119775-11340
- Recmar® Seal kit Yanmar 3GM radiator 121450-13251 128297-44030 128695-44070
- PoseidonMarine® Trim Ram Rebuild kit Volvo Penta cylinder 872612 inch thread
- PoseidonMarine® Trim ram seal kit Volvo Penta trim cylinder 853439 square capped
- Recmar® Rod Bearing 4.3L V6 Mercruiser Volvo Penta OMC 21179992 23-11992 STD
- PoseidonMarine® Trim Cylinder Rebuild kit MerCruiser 806191T 87400A2 1.89″ O.D.
- Recmar® Cylinder Head Bolt Volvo Penta & MerCruiser inline 4 10-34510 3857900
- STA-BIL® 22207 Storage Fuel Stabilizer 473ml Petrol
- Recmar® Shaft oil seal Johnson Evinrude 802278 0321480 0777541 321480
- PoseidonMarine® Propeller shaft oil seal Johnson Evinrude 321453 69188 18-2051 18-2026
- Recmar® Shaft oil seal Johnson Evinrude 327031 0300599 802292 30900T
- SLP® Injector sleeve kit for Volvo Penta MD1 MD2 MD3 MD11 MD17 897170
- SLP® valve seat exhaust D4 D6 3581862
Frequently Asked Questions
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What should I do if I notice water in the lower unit of an outboard or sterndrive?
If you notice water in the lower unit, stop using the boat immediately and drain the contaminated oil as soon as possible. The next step is to identify the source of the leak. The most common causes are the oil plug drain seals and, most frequently, the propeller shaft seals. Approximately 90% of water intrusion cases originate from worn or damaged propeller seals.
Poseidon Marine stocks a wide range of high-quality marine-grade propeller shaft seals including: 851407, 853807, 853808 for Volvo Penta Duo-Prop drives, 3593663 for various Saildrive units, and 321480, 321481, 327031 for Johnson & Evinrude outboards. -
What happens to the fuel during winterization?
The most effective winterization method is to **fill the fuel tank completely**, reducing internal condensation. A fuel stabilizer should then be added to prevent gum and varnish buildup caused by separation or oxidation of lighter hydrocarbons.
Recommended products offered by Poseidon Marine include:
• **STA-BIL® 22207** – Storage Fuel Stabilizer (473 ml) for petrol engines
• **STA-BIL® 22254** – Storage Fuel Stabilizer (946 ml) for diesel engines -
What are the benefits of a stainless steel elbow for Yanmar marine diesel engines?
Stainless steel exhaust elbows (316L grade) offer significantly longer service life than cast iron equivalents. They resist corrosion, prevent carbon buildup inside the exhaust passage, and help maintain optimal engine performance. Cast iron elbows often accumulate soot, resulting in restricted water flow, overheating, corrosion of the heat exchanger, and potential turbocharger damage.
A top-selling model is the **Recmar® Stainless Steel Exhaust Elbow Yanmar 4LHA / 6LP – 119773-13501**. -
What warranty is offered on SLP cylinder liners and other parts from the Swedish brand?
All SLP spare parts include a **36-month or 6,000-hour warranty** (whichever comes first), covering manufacturing and material defects, provided the parts are used normally and service intervals are respected.
Popular components include injector sleeve kits **897170** and **889970**, and high-demand valve seats for the Volvo Penta D4/D6 engines (**3581862**). -
What happens if a mechanical fuel pump fails on a Volvo Penta or other marine engine?
A failing mechanical fuel pump may cause inconsistent engine performance, difficulty starting, unusual noises, or fuel leaks if the membrane is damaged. Poseidon Marine stocks a comprehensive range of mechanical pumps for both diesel and petrol engines.
All Poseidon Marine-branded pumps, such as the **Fuel Pump for Volvo Penta MD1 / MD2 / MD3 / MD7 / MD11 / MD17 / 2001 / 2002 / 2003 – 833323**, are manufactured within the European Union. -
How do I fix a leaking trimming cylinder or hydraulic cylinder on a marine engine?
The repair method depends on the specific model. Most trimming and hydraulic cylinders can be serviced by disassembling them and replacing all seals. However, if the ram shaft is deeply scratched or corroded, replacing seals alone will not resolve the leak.
Poseidon Marine manufactures several replacement rams: **21840806, 21840807, 3860881, 872612**, along with many trim cap kits including: **86191T, 87400A2, 853439, 872612, 3860881, 3854247, 3857470, 3857471, 3885196**. -
How do I clean a clogged heat exchanger?
The descaling process varies by engine design, but for a typical freshwater-cooled unit (e.g., Yanmar 3GM), the procedure is:
1. Remove the end cap(s) and extract the core.
2. Soak the core in an appropriate descaling solution; rinse thoroughly per product instructions.
3. Perform additional maintenance such as housing cleaning or repainting.
4. Reassemble using new seals and gaskets.
Helpful kits include the **Recmar® Seal Kit for Yanmar 3GM radiator – 121450-13251 / 128297-44030 / 128695-44070**. Poseidon Marine also offers heat exchanger seal kits for Volvo Penta and Yanmar engines.