Parts for the Westerbeke, Universal or Yanmar are available world-wide.
Most of the current manufactured engines use softer engine mounts to minimize vibration transmitted to the hull, soft mounts allowing more movement, create another problem as the movement is transmitted to the propeller shaft and subsequently induce stress to the packing gland, packing material and cutlass bearing; of the three, Yanmar tends to move more than the other two, especially when the engine is cold. Gross lateral movement in the propeller shaft causes premature wear in the packing material, subsequent increased periods of readjustment to minimize water intrusion and premature failure of conventional packing material. We advise our customers who install the P.S.S Drip-less packing glands to start their Yanmar engine when cold, to raise the RPM up to 1,000 until warm to minimize excess propeller shaft lateral shaft deflection, unseating the carbon seal and subsequent water entering the bilge. Once the engine is warm, the problem seems to diminish.
We have found using systhetic packing material and dripless packing in conventional packing glands works best with the new engines.
Regarding engine mounts, Yanmar mounts are very durable, they have an upper mount place with a stud and a lower plate that bolts to the engine bed, with rubber bonded between the two plates. Westerbeke and Universal use what they call a “fail-safe” mount, wherein, if the rubber fails, the upper and lower sections of the mount are mechanically connected together preventing total loss of support.
Regarding noise levels, Westerbeke and Universal diesels are considerably quieter than the Yanmar engines. We service and repair aproximately 650 diesels per year about 30% of these are Yanmar, good engines, but the little buggers are noisy, sorry Yanmar.
I haven’t had much feedback regarding the new Y-series Yanmars engines which replace the GM engines, they are to few in numbers to get an opinion on performance. The photographs conflict with the engineering drawings regarding the exhaust system, one shows the old U-style cast iron exhaust mixing elbow and the other shows a stamped steel elbow. The cast iron elbow screws on with a left handed 1-1/4" pipe thread requiring the addition of their special left and right hand threaded SS pipe coupling ($35),cost and time to change.
Both the Universal and Westerbeke engines use a V-band coupling, replacement elbows come in kit form, elbow, pipe fittings, v-band coupling, reducing the replacement time to 1/3 of the Yanmar cast iron unit. The cast iron elbow require a torch, big vice, pipe wrenches, cheater bar, sledge hammer to knock it loose, usually figure on anywhere from 2-3 hours start to finish for replacement; with the v-band coupling, barring any unforseen problems, should only take 1 hour to replace. The Yanmar stamped steel elbow should be some what easier to change and less expensive than the cast unit. The Westerbeke and Universal elbows are made of aluminum for reduced overhead weight, there is no significant difference in durability regarding material the elbows are made from.
Regarding cooling systems, all are straight forward and are easy to maintain. Yanmar has finally joined the rest of the industry in turning the seawater pump around to allow impeller replacement without removing the pump in the new Y-series, unfortunately, it still remains a belt driven pump. Belt driven pumps experience sided loads, improper adjustment of belts either slips when loose causing loss of cooling water, burned and prematurely worn belts, require periodic adjustment and replacement of belts. Excess side loads from over tensioning of the seawater pump belt can cause premature seal, bearing wear and pump failure. Most Yanmar pumps are not made by Yanmar, but are protected by manufacturing agreement, limiting your source of replacement to the dealer network. Westerbeke/Universal seawater pumps for the 30 hp range are gear driven pumps, as such, experience no side load, no belts to adjust or replace and tend to last longer if properly maintained. Westerbeke/Universal pumps are made by Sherwood and Johnson pump CO., pump and parts are not protected by manufacturing agreement, parts are readily available from the dealer or a multitude of other marine engine parts supplier as well a pump rebuilders.
The Yanmar heat exchangers are incorporated into the exhaust manifold, isolated by rubber O-rings, no zincs are required, easy to maintain, no history of problems. Both Westerbeke and Universal use a heat exchanger seperate from the exhaust manifold and require periodic zinc replacement, plan on replacing the exchanger at the 10 year mark. Both type exchanger should be removed and properly cleaned every 4 years to ensure proper cooling.
Transmissions: The Yanmar KM2P/KM3P tend to be their weak point, they hold up well if not abused, high speed shifts and folding propellers tend to shorten the life span; common problem is worn front housing bearing recess, which allows the bearing race to spin, excess end-play, movement, resulting in a loud whining sound. I suspect the large flat front housing could use additional reinforcement. The Westerbeke 30B Three comes with the JS transmission, joint venture with ZF (which now owns Hurth) and a spanish firm, early models were overly sensitive to improper shift cable misadjustment resulting in failure and subsequent replacement; later models have been redesigned to compensate for slight rigging errors. It is important to note, even early models that were less tollerant to improper installation, if installed properly were just as durable as any other transmission. Universal diesels use a ZF gear manufactured in the ZF factory. We don’t know why, other than gear ratio availability, Westerbeke and Universal use different gear boxes in the 30/35 hp range, thus far both gears are performing well without failure.
As noted earlier, MER a large transmission rebuilder and retailer in Seattle has come up with a drive plate and adapters to replace the Yanmar KM2P/KM3P with a ZF transmission for around $1300, slightly less then the retail cost of the Yanmar tranmission, less drive plate.I guess there is someone else out there who believes there has to be a better mousetrap.
Food for thought,