Having just ordered a new
yanmar 4jh
diesel be advised that this is now an electronically controlled
engine . Any number of
electrical glitches or issues can and will disable this
engine . No amount of tinkering or expert mechanicing will make it run again. It is loaded with sensors and all manner of
electrical and electronic stuff . I haven't found a dealer /
mechanic yet who has any idea how to
work on one of these things . I called mack boring to see if I could carry a spare ecu and they told me absolutely not - the only way to deal with a problem is to remove the ecu and send it to them and they would replace and re-program it and send it back ,then if you can find a factory trained
yanmar guy with a
laptop and
software he can get you going again . Maybe . Do you need to reprogram the ecu to replace any one of the many sensors whose failure will leave you engineless ? Expense ( major ) and time ( major ) aside this is just not acceptable for anyone who plans on traveling more than a few miles from a yanmar tech . Hit by
lightning ? Forget about using your engine afterwards . I've read about ecu 's that were fried because the key switch was turned off before the stop switch . Is a bad ground enough to fry your ecu in the middle of no- where ?Several years ago I was at Hinckleys in
Maine and a freshly launched jet
boat wouldn't start . Nada . There wasn't a
mechanic there , and there were some top notch mechanics , that could get a peep out of that engine . They had to fly in a yanmar tech to fix the
electronics . If you search the sailing / cruising
forums on line you will encounter numerous stories of unexplained failures of ecu's after less than 50 hours ! When I first looked at the new engine they shipped me and realized it was electronic ( I had been shown a new install of a 4jh mechanical injection engine ) I tried to send it back but was given a run around .Dealing with yanmar is like dealing with a stone wall . Note that neither yanmar nor Mack boring have an
email address . If anyone wants to buy the latest in smooth , clean , efficient
diesel technology I've got a brand new engine
for sale .