Removing the alternator on a 4BY2 180

Hydraulicjump

Well-known member
Joined
Feb 10, 2011
Messages
646
Fluid Motion Model
C-30 CB
Hull Identification Number
FMLT2911F415
Non-Fluid Motion Model
Necky Looksha VII, Liquidlogic Remix, Jackson 4Fun
Vessel Name
La Barka (2015)
My Christmas project is to have my psychotic alternator (actually, the problem is the voltage regulator) rebuilt. Of course, this means pulling it out of that cramped hole in the boat we call an engine compartment. Have any of you attempted this and do you have advice? I am pretty sure that the serpentine belt removal will be the biggest challenge. I believe there is a tensioner on it which I hope I can get to without pulling lots of things apart, but I can't find any details on-line about how it works and the tool that is required to rotate it. If any of you experts have advice--besides to remove the negative battery cable on the engine battery (I remember that one the hard way from working on an old car)--I would welcome the input. Feel free to pm me.

And happy holidays to the tugnuts crowd from rainy northern California.

Jeff
 
The tensioner just has to be engaged with a socket and breaker bar. Sorry, but it has been a while since I replaced the serpentine belt and can't remember the size of the socket. You just push and that releases the tension while you remove the belt. This is an easier task if done by two people. One person in the cockpit releases the tension and another working through the step access can remove the belt. The belt runs behind the raw water pump belt, but you can most likely get it off the alternator without the need to remove the raw water pump. If you want to send me your e-mail I can look up in the manual I have if there is a recommended sequence for removal of the alternator.

Take care,

Mike Rizzo
 
I removed that belt w/o moving the tensioner. It wasn't bad, I just worked it off. First one side, then the other. On is a little different. I used a socket on the tensioner, it was more or less finding the right position to lie down in. It only took a few minutes. I know the crank is 22mm, but I forgot what size I used for the tensioner. I have some plans to work on the boat tomorrow, I will let you know then.
 
Chock this one up as an easy DIY if you ever need to remove the alternator. 1) take the negative lead off the start battery, 2) put a 23 mm wrench on the belt tensioner and rotate counter clockwise to relax the belt and take it off, 3) unscrew the idle pulley (requires an Allen key) so you can get to the lower alternator bolt, 4) take the positive cables off the alternator, 5) remove the two bolts holding the alternator in (the bolts required a 10mm female torks socket wrench). An hour project if you have all the tools.

Now to see if the alternator shop can find the gremlin. Thanks for everyone's help.

Jeff

Ps: for some reason, there is no connector/plug in the alternator. There is a slot for the connector, but no cable. This struck me as odd, but given the fancy electronics of the boat, it may be superfluous? There certainly is no monitor for the alternator that I am aware of.
 
Late reply to an old thread but I'm planning on replacing the serpentine belt on my 4by2 180 Yanmar. Would anyone per chance have a picture of the belt tensioner / location? I have good access through a removable step but am not sure what the tensioner looks like or its exact location. Thanks, GF
 
A question to GaylesFaerie about your removable step:
Have you had any concerns about weight when stepping on the step when in place? What about rattling or other noise from the step while underway?
I'm thinking of doing the same thing so I have easier access to the front of the engine, so any other considerations or pitfalls about the engineering of removing the step would be greatly appreciated. Thanks.
 
Thank you Howard, glad to see you still on the forum. I assume the tensioner is the wheel pressing on the smooth side of the belt. Is it spring loaded somehow and one just needs to push against it to release tension on the belt to remove it?

Trisailor, the removable step was done by the second owner of the tug who hired a professional to do the work so I don't have many details. It is rock solid (seriously) with regard to holding weight. It appears he may have reinforced the step underneath which is about 1" thick so it can hold weight. He used two tapered wooden cleats to hook the bottom of the step cutout (to get a snug fit I assume) and the sliding latches seem to be just off center enough from their catches to fit snuggly as well. Not a whisper of rattle or any noise that I can hear. None from the engine compartment either. Hope this helps, GF
 
Thanks GF,
I looked closely at the pictures and your install is close to what I had in mind.
 
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