Aqua Power NEW 1452 Upper Crankcase Oil Seal 1.625 x 2.125 Rep: OMC 339620 0810

Aqua Power Upper Crankcase Oil Seal — Part Number 1452

Brand: Aqua Power | Condition: New Old Stock (NOS)

Aqua Power part number 1452, the upper crankcase oil seal for Johnson and Evinrude V4 and V6 outboards, replacing OMC part number 339620. It measures 1.625 in shaft bore × 2.125 in outside diameter × 0.250 in wide. This is new old stock from long-term inventory — Aqua Power is a long-established American marine aftermarket manufacturer specialising in OMC, Johnson and Evinrude replacement parts.

The upper crankcase seal is the one that keeps a two-stroke's primary compression where it belongs. The crankcase is a pumping chamber that has to hold both vacuum and pressure on every single revolution, and the upper seal is what stops that pressure escaping around the crankshaft at the top of the block. When it hardens or the lip wears, the symptoms are the classic ones that get misdiagnosed for weeks: hard starting, a motor that won't hold a steady idle, hesitation off idle, and a lean-running top cylinder — which on a big V4 or V6 two-stroke is the first step toward a scuffed piston.

What makes this seal worth having on the shelf is the fitment. One size covers the V4 65 to 140 HP range from 1973 through 1998 and the V6 100 to 300 HP range from 1976 right through to 2019, across both two-stroke and four-stroke models. That is close to fifty years of Johnson and Evinrude production on a single seal.

Condition Details

New old stock. The seal is unused and has never been installed. As with all warehouse-stored inventory, the packaging may show shelf wear, dust, fading, price stickers, scuffs or minor crushing from stacking. The seal itself is undamaged, with the sealing lip intact and supple, the garter spring in place, and the case round and undistorted. Elastomer seals do have a finite shelf life, so we recommend inspecting the lip on arrival and before installation. Please review all photos, as what is pictured is what you will receive.

Specifications

• Part Number: 1452
• Part Name: Upper crankcase oil seal
• Manufacturer: Aqua Power
• Shaft Size / Inside Diameter: 1.625 in
• Outside Diameter: 2.125 in
• Width: 0.250 in
• Location: upper crankcase, crankshaft seal position
• Sold: see listing quantity
• Aftermarket replacement for the OMC original

Superseded & Cross Reference Part Numbers

Aqua Power 1452 replaces the following. Always confirm against your own application guide before ordering.

• Aqua Power: 1452
• OMC / Johnson / Evinrude: 339620, 322575, 318451
• Sierra Marine: 18-2074
• GLM Products: 86440

If your parts list or dealer quote shows OMC 339620, 322575 or 318451, or Sierra 18-2074, this listing is the Aqua Power equivalent for that reference. OMC 339620 is the number most commonly quoted for this application, so buyers searching that number are in the right place.

Features

• Dedicated marine aftermarket seal from a manufacturer specialising in OMC, Johnson and Evinrude replacement parts
• Precise 1.625 in bore with 2.125 in OD and 0.250 in width, so it presses squarely into its bore and runs true on the crankshaft
• Maintains the primary crankcase compression a two-stroke depends on to transfer fuel and air into the cylinder
• Correct lip geometry with the garter spring correctly tensioned, which is what keeps lip contact as the crankshaft turns
• Cures the hard starting, unstable idle and lean top cylinder that a worn upper crankcase seal produces
• Exceptionally wide fitment — V4 65–140 HP and V6 100–300 HP, covering roughly 1973 through 2019
• Covers three separate OMC part numbers on one seal
• Single-use by design — replaced at every powerhead teardown, never reused

Application

Fits Johnson and Evinrude outboard motors across an unusually long span:

V4, 4-cylinder:

• 65 through 140 HP, various years 1973 to 1998
• Including the 115 HP (1973–1998) and 135 HP (1973–2001)

V6, 6-cylinder:

• 100 through 300 HP, various years 1976 to 2019
• Including 200 through 300 HP models in both two-stroke and four-stroke configurations

This seal size served OMC and later BRP across nearly five decades of production, which is why it crosses to three different OMC part numbers. Because the upper crankcase assembly varied across that span, buyers should confirm Aqua Power 1452, or OMC 339620 / 322575 / 318451, against the exploded crankcase diagram for their specific model and year before ordering. If you send us your model number and year we will check it against the parts catalogue for you — and if you have measured the seal you are replacing, send us the figures and we will compare them against the dimensions above.

Why Choose Aqua Power?

Aqua Power is an established American marine parts manufacturer that has specialised in replacement components for OMC, Johnson and Evinrude outboards for decades — the engines whose original manufacturer no longer exists. That focus matters: Aqua Power builds to the original OMC specifications for applications the OEM has long since abandoned, and in many cases Aqua Power stock has outlasted the genuine parts entirely. For a seal on a motor family that has been out of OMC production since 2001, a dedicated marine aftermarket part is often the practical choice over hunting NOS.

Returns

We accept returns through eBay's standard 30-day return request process. If the part is not what you need, simply open a return request through eBay within 30 days of delivery and we will take care of it.

Thank you for looking. We are a small parts business and we take real care in identifying, describing and packing every item we list. If anything about this part is unclear, or if you want additional photos or measurements before you buy, please message us — we would much rather answer a question up front than have you receive something that is not right for your machine.

If there is any problem at all with your order, please contact us first and give us the chance to make it right before leaving feedback. We respond quickly and we will resolve it.

QBS Parts, Inc — Gardena, CA