Engine Mounts (12mm Stud)


$ 120.00

| /

Size Guide


  • Designed for marine use, accepts propeller and engine thrust in both directions.
  • Offers a fail-safe design.
  • Are height adjustable.
  • Pre-loaded to reduce movement.
  • Slotted holes in the base to assist in alignment.
  • Mount types to fit all applications.

The R&D Marine Engine Mounts are designed specifically for the rigors of marine applications. The mounts are stiff enough to absorb forward and reverse propeller thrust yet soft enough to isolate drivetrain vibrations from the hull.

To help increase the longevity of the mounts, all steel parts are zinc plated and passivated to limit corrosion. The rubber component is covered by an oil shield to protect it from petroleum-based products.

R&D Marine mounts are preloaded based on the combined engine and transmission weight to limit engine movement. To facilitate the ease of installation, the mounts are height adjusting, and the mounting holes in the base of the mount are slotted to assist in the alignment of the drivetrain.

Available for most brands such as Yanmar, Perkins, Universal, Westerbeke, and many more.

Determining Engine Mount Weight Capacity

Below are the formulas to use to determine the required pounds per engine mount.


Front Engine Mount

(W x 0.4) x 0.5 = lbs per mount

Back Engine Mount

(W x 0.6) x 0.5 = lbs per mount

W = weight of engine and gearbox


Total weight of engine and gearbox = 1,200 lbs.

Front Engine Mount

(1,200 x 0.4) x 0.5 = 240 lbs per mount

Back Engine Mount

(1,200 x 0.6) x 0.5 = 360 lbs per mount

General Weight Distribution
R&D Marine Engine Mount weight distribution
  1. Find the center of gravity by balancing on a roller (If possible)
  2. If the center of gravity cannot be found, assume a weight distribution of 60% on the rear engine mounts, with 40% on the front engine mounts (if the rear engine mount is in line with the flywheel)

Technical Specifications

Part # Stud Size Capacity Per Mount Foot Print Mount Pre-Loaded Deflection Minimum Height Maximum Height
800-038 12mm 30-90 lbs 4" 0.07" 0.07" - 0.14" 2.03" 3.9"
800-039 12mm 70-170 lbs 4" 0.07" 0.07" - 0.14" 2.03" 3.9"

Customer Reviews

Based on 14 reviews
Paul Bailey
Engine Mounts

Not knowing which type of mounts that were your required, your technical support person went over the various types which was extremely helpful since there were no information available from the engine manufacturer.

N Haggard
Yanmar replacement mounts

Fits and works great!

Ron Ricci
Happy Camper

Great pre-sale customer support!! The mounts were a perfect fit.

I picked these because of the stainless steel shield over the rubber parts. This, along with the coating on the base is a much better design than the Vetus mounts that were replaced. The bolts that hold the mount into the stringers were also replaced since the base is thicker than the old mounts.

Norman Facey
Good work!

1) I chatted online with Eric Young who was excellent in helping me to identify my old mounts & provide order number for new
2) a couple days later, once I’d confirmed the old mounts were toast (threads rusted so bad they were unlikely to be adjustable for realignment) I was able to go online & easily order the correct replacements
3) AND specify rapid shipment vis UPS that actually worked across the border and up into rural Canada.
Shipment worked, mounts bolted directly in place, and alignment was easy. Lots o’ stars for PYI.

Percy Roberts
5 star all the way

great product and service, set arrived with one mount wrong weight raqnge replacement was overnighted along with prepaid return lable for wrong mount. The R&D mounts are high quality, comparing the original Yanmar mounts to the R&D mounts I'll just say is like comparing a ford pinto to ferrari