OFFICIAL 390/40 Motor Yacht Thread

i just got my custom mattress from HMC. My old mattress was missing the tag. Each mattress tag # is linked to a certain serial number boat. I patterned my mattress and I couldn;t be happier. Got a 9 1/2 inch. Sweet.

I sat on a few HMC had at Annapolis boat show which did you go with I liked the pillow topper that was most expensive one of course
 
A quick check on YachtWorld has a couple for sale in Florida right now. Have you checked those out at all?
I did see them but I’m in California, so a little worried about transporting them out here. I know the top has to come off and possibly other stuff for road transport. Other option is by boat to Mexico and then drive it by water the rest of the way to LA. Not many of them on the west coast unfortunately.
 
I’m looking for opinions on how the 390/40MY handles in the ocean? I’ll be boating in the Southern California part of the Pacific. Thank you.
 
Thanks for your reply Al. I like the QSB engine as you have a lot better that the 480CE. I think they started offering those in 2006 or 2007. Right now the seller wants about $220.000 which I think is high given the risk about the engines.
I suspect you have moved on, in case not, if the boat has 480s and does not have the new/upgraded head, Cummins part# 4942463, I would ask for a 30K allowance to swap the heads. I rebuilt one after dropping a valve seat, swapped the head on the other. Cummins came out with a TSB in 2006 addressing the problem and changing the part #.
 
I suspect you have moved on, in case not, if the boat has 480s and does not have the new/upgraded head, Cummins part# 4942463, I would ask for a 30K allowance to swap the heads. I rebuilt one after dropping a valve seat, swapped the head on the other. Cummins came out with a TSB in 2006 addressing the problem and changing the part #.

Thanks for the info on the part number. Tony over at SeaBoard lists the new cylinder head as part 3931925. I believe both refer to the new/latest version of the cylinder heads.
I’m still searching for my boat and will make sure the engine gets a good looking over. Also heard to prop it as per the 450. Sorry to hear you had the dreaded dropped valve.
 
All I can say is that you should order directly from Cummins through a Cummins distributer. That way you are getting the most recent version of a particular part, 4942463 is the updated head. That was the case in 2006 when the TSB was issued and in Jan of 2020 it had not changed. There were a few other updated part numbers along the way, prior to 2006 but they are no longer available from Cummins. Call Cummins and they can tell you if a particular part number is still valid. There are a lot of old part numbers out there at reduced prices.
 
All I can say is that you should order directly from Cummins through a Cummins distributer. That way you are getting the most recent version of a particular part, 4942463 is the updated head. That was the case in 2006 when the TSB was issued and in Jan of 2020 it had not changed. There were a few other updated part numbers along the way, prior to 2006 but they are no longer available from Cummins. Call Cummins and they can tell you if a particular part number is still valid. There are a lot of old part numbers out there at reduced prices.

Your suggestion to order directly from Cummins is well taken for both the heads and other parts. Thanks for following up.
 
Your suggestion to order directly from Cummins is well taken for both the heads and other parts. Thanks for following up.
FWIW, took about 30 hours to swap one head, below is the parts list minus the head which was around 3800

C115507D-DCF3-439C-9871-53E75C8C4CE7.jpeg
 
FWIW, took about 30 hours to swap one head, below is the parts list minus the head which was around 3800

View attachment 108188
Thanks for posting the parts list invoice. That could come in very handy. 30 hours labor for one, wow. Yes $30K allowance off the purchase price makes sense for changing heads on both engines.
I was right behind a 390 MY out on the ocean today in 4’ seas and it seemed to do quite good. Much better than my current boat.
 
Yes, the boat is very stable in rough seas. Where are u located?
 
Is there anyone on here that has a older 390, I need so help on some wiring on my '85
 
Wondering if anyone has a list to starboard side with their 390.
Our 390MY, yr. 2003, first season for us. We are noticing a list to the starboard side of the boat (when sitting still, and travelling). To keep the boat level we found filling the port side tanks to full, and the starboard to 3/4, we can balance the boat. This is taking into account that no personal items have been added to the boat. As long as the starboard tank remains a 1/4 difference from the port tank, the vessel remains level (1/4 tank of diesel= approx. 275 lbs.) Anyone else experiencing same issue? The gen is on the port side, house batteries on the starboard. No water in bilge, everything bone dry. Purchase survey noted no water saturation in plys, nothing abnormal.
Twin 480CE Cummins.
thanks again, hope everyone having a wonderful day on the water!
 
Wondering if anyone has a list to starboard side with their 390.
Our 390MY, yr. 2003, first season for us. We are noticing a list to the starboard side of the boat (when sitting still, and travelling). To keep the boat level we found filling the port side tanks to full, and the starboard to 3/4, we can balance the boat. This is taking into account that no personal items have been added to the boat. As long as the starboard tank remains a 1/4 difference from the port tank, the vessel remains level (1/4 tank of diesel= approx. 275 lbs.) Anyone else experiencing same issue? The gen is on the port side, house batteries on the starboard. No water in bilge, everything bone dry. Purchase survey noted no water saturation in plys, nothing abnormal.
Twin 480CE Cummins.
thanks again, hope everyone having a wonderful day on the water!
Mine is pretty level, if at all a little bit to port. Maybe it's your battery bank. My house bank is to port, thrusters to starboard. Washer/dryer is also to port. Hulls are designed to be level so a list is almost always a weight distribution issue. To the extent it bothers you, you may want to install permanent ballast; lead is usually used due to its density. I would do that up forward to also bring down the bow. The bow-up tendency of the 390/40 hull has always bothered me more than any list although I haven't really done anything about either other than to keep the water tank a little light on long trips. Another thought is just to fill up the fuel tanks but then always run the generator off the port tank which will serve to slowly correct your list.
 
BTW, the 2 batteries on the starboard side are wired in series to make 24 volts for the bow thruster. The port side are 2 banks of 2, wired parallel each pair starts an engine and serves as a house battery bank. One of the banks also starts the generator
 
No list to port or starboard on our 2005. Difference on ours is both generator and house battery bank are on port side. If I understand what you posted, seems your house battery bank is on the starboard side. If correct, this may be why batteries were moved from starboard on 2003 to port on 2005.
 

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