Re: [Amel Yacht Owners] I dont think it is the same engine as mine Isolated ground on a Yanmar
toggle quoted messageShow quoted text
I understand what the new wiring kit does, however it was made for a different engine.
I have ha 3 4JH yanmar engines and they were all identical except one did not have a turbo, one did , and my current one has the turbo and intercooler.
The theory is the same and the schematic diagram might look the same but it really depends on how the actual engine was wired.
Kimberlite Amel Super Maramu #376
From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Saturday, April 01, 2017 12:55 PM
Subject: Re: [Amel Yacht Owners] I dont think it is the same engine as mine Isolated ground on a Yanmar
Every engine will be somewhat different, but the "Amel isolation wiring theory" should be the same. The information I searched and found on the Yahoo Amel Group website was originally posted by Kent and, I believe, that it refers to a newer Yanmar than the Yanmar in Kimberlite. I do not know believe that we know the hull # of the boat that this thread is referring to.
The photo that Bill posted shows a different wiring setup than what was on my Yanmar.
If you will note in Bills photo all of the ground wires run to the valeo solenoid and are not connected to the big black wire that I mentioned. Also this engine is not mounted in a boat.
Bill, are you sure this is a 4jh3hte engine and not a 4jh4hte or the newer rail engine that I believe Kristie used?
These photos seem to show the valeo solenoid mounted under the starter motor on the outboard side of the engine. Mine is mounted inboard near the starter relay on the forward side of the engine. It also shows 3 diodes and my engine had only 2. It also looks like the oil filter is in a different place than is on my engine.
This engine does not look like mine. It also appears that the injector pump is further aft than on my engine. The wiring is completely different and according to Amel there is no wiring diagram for my engine.
If I remember this wiring diagram and the isolation kit were sent to someone who was installing a new engine in their boat using a stock Yanmar and the wiring kit was sent to make the engine isolated.
Note the transmission oil cooler is mounted under the turbo..
Kimberlite Amel Super Maramu #376
The answer to your question requires more words than I have this morning, but I can answer why...
Amel did this to eliminate galvanic corrosion. Amel has done more than any other boat manufacturer to eliminate galvanic corrosion. This is the reason that your mechanic has never seen it.
There is a wiring diagram on the Group website at:
Where are you, what model Amel, and hull#?
What was Amel’s thinking on the need for an isolated ground for the generator and 185 amp alternator? It seems to confound local Yanmar techs as there are no Yanmar wiring diagrams available to them. Their initial reaction is to want to take the isolated ground out somehow.
This problem started as a non-functioning tachometer. The flywheel sensor ground is indeed bad, pointing as you say up the line on the wiring loom or somewhere else on the engine. A jumper wire placed on the tach sensor ground connector to another engine ground point brought it to life. All was well until the genset was started on passage. Genset started, isolated ground started clicking rapidly, engine failed to start, isolated ground was open, top push button engaged, engine would start, but tach indicated interference.
In my initial thought on the initial tach issue I was thinking a bad ignition switch, but since finding that the tach sensor ground wouldn’t work, it points to somewhere in the loom or on an engine connection in my mind. Opening the wiring loom on the engine would be a big job for me, if it were in the loom from the engine to the helm, that would be another matter entirely. Jumping the ground to get the tach working was too easy. Obviously, there is a larger problem. What do you think the likelihood of the ground short being in the engine wiring loom? Could it be a bad sensor or relay in the same circuit? Does a wiring diagram of this motor with the isolated ground shown exist?