I purchased two 4JH3s new in 2000. Within 18 months, the oil
pans were dripping oil
into the bilge
, the intake silencers were rusting inside and out and the fuel
injectors and fuel
lines had corroded and were dripping diesel
. Both engines must have been painted with half a spray can, because they also forgot to paint
the backside of any fittings, sheaves, etc. Reported these deficiencies to both Yanmar Marine
USA and the regional distributor and received the response that they "...can't be held responsible for every installation
Pulled the oil pans and took them down to a local metal shop and had replacements
fabricated from 1/4" 6061 aluminum
plate; cost was $135 each
. Other than holding an additional quart of oil and requiring longer bolts, the fit was perfect. Plus, I added a threaded drain fitting at the lowest corner (to which I attached a braided hose that allows me to suction all of the oil for oil changes). That was more than 10 years ago and they still look new (and don't leak).
The air silencers were ultimately replaced with Yanmar
OEM plastic silencers and the injector lines were braised.