Official 390 E.C. Thread

gdavis67 said:
So I got the refer out last night, took about 20 minutes and was pretty easy. Up the stairs and out of the boat with no problem. The refrigerant used on mine is 134A which was the standard refrigerant at the time for appliances and cars. This refrigerant is no longer used, but is still available to HVAC shops and auto repair. You can also buy re-charge kits at your local Auto Zone, etc. The problem is there is no charge port installed on appliances like there is on A/C units. There are many clamp on piercing ports you can buy to do this, but they all leak. I took mine over to a friends HVAC shop and we are going to solder a port in the line, pump down the system into vacuum (decontaminate), and re-charge with a scale for quantity of 134A. Keep in mind, my refrigerator still worked - I could hear the compressor running, cooling fans ran, and it got cool, just not cold. If your compressor dies, this is not worth the effort. I will post pictures of the removal and install process sometime this weekend. I will also hopefully be able to share good news on the re-charge effort as well. We'll see.
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Flag question: I'm reading that the recommended size for our boats is anywhere from 20"x30" to 24"x36". What size do you fly for a custom design (i.e., not a national flag)?
 
DougLas said:
Ok what happened with the recharge did it work?
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Yep, sorry for not posting sooner. Had a friend solder in a re-charge valve (the clamp on ones are notorious for leaking) and recharged with 134A. Two weeks and still running like a top, never been this cold. The removal ended up being very easy, had to unscrew the shelf on top of the fridge to get it out.
 
So I finally got the opportunity to get the boat out this weekend without the dingy in tow for a good run out in the lake and noticed I could not get the motors to run past about 3500 rpm. The WOT on the 7.4 should be around 4200 if I remember correctly. I put new caps, rotors, and plugs in this winter during layup. I have not checked timing or anything else at this point as I just noticed this weekend. Can anyone weigh in with their WOT on the 7.4 gassers and suggest items to check regarding this issue? I did have full fuel tanks and a full tank of water on board with six adults on board as well.
 
No, they are 4 blade Nibrals put on by the PO. I forget the pitch on them now, but when I checked last year, they were the correct size and pitch for the boat. I never did write down the rpm's I saw last year, but if I remember correctly I could get around 4k +/- a little.
 
Bottom is clean and freshly bottom painted this year. Hull speed isn't really the problem, it's WOT RPM I'm concerned about.
 
gdavis67 said:
So I finally got the opportunity to get the boat out this weekend without the dingy in tow for a good run out in the lake and noticed I could not get the motors to run past about 3500 rpm. The WOT on the 7.4 should be around 4200 if I remember correctly. I put new caps, rotors, and plugs in this winter during layup. I have not checked timing or anything else at this point as I just noticed this weekend. Can anyone weigh in with their WOT on the 7.4 gassers and suggest items to check regarding this issue? I did have full fuel tanks and a full tank of water on board with six adults on board as well.
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WOT rpm should be 4200-4400. 3500 is too low but you were pretty loaded up and 4000 would be acceptable. If your throttles are advancing fully and all else is in good shape I suspect too much prop pitch. I changed my OEM 19X18 3 blades for 20X17 3 blades and get just over 4000rpm and 33 mph with medium load. I find that acceptable. You could double your rpms using a digital tach just to be sure yours are accurate.
 
hottoddie - great info! I will have to go back through my documentation and look up the size and pitch of the props. I have the build and data sheet for them on the boat.

I have been thinking about adding digital tachs to the boat for a while because I don't really trust the 28 year old mechanical ones that are there now. However, I don't really want to just toss them because I like keeping the original look and equipment. I was thinking about adding these as a more accurate back up. I'm just not sure that they will take the factory tach signal from the distributor as the input signal and give me correct readings. If anyone has tried these and can give me your experience that would be great. Or, if you have found another type of digital add on type tach that you can show me I would like to see that as well.

https://www.ebay.com/itm/DIGITAL-RE...m=392075645537&_trksid=p2047675.c100005.m1851
 
Are there any other 1990 390 owners out there that have toggle switches at the helm for your ignition switch? Mine has keyed switches at the panel in salon and toggles at the dash. They are OFF/ON/MOMENTARY ON type switch. I have one that is starting to go bad and need to replace it. I have searched the part number from the original switch and have not been able to find the correct replacement. I have tried digi-key and several other websites. This is a Carling switch, but no luck sourcing the correct switch.
 
gdavis67 said:
Are there any other 1990 390 owners out there that have toggle switches at the helm for your ignition switch? Mine has keyed switches at the panel in salon and toggles at the dash. They are OFF/ON/MOMENTARY ON type switch. I have one that is starting to go bad and need to replace it. I have searched the part number from the original switch and have not been able to find the correct replacement. I have tried digi-key and several other websites. This is a Carling switch, but no luck sourcing the correct switch.
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Try greatlakesskipper.com I bought some Carling switches from them last year for the windshield wipers.
 
This has been "the summer of the water tank" in my opinion. Look back through this thread over the last couple of months and you will see many examples of this job. Poly tanks are less expensive, more options, and possibly more durable; aluminum tanks are also available. Drill access ports under the tank, dig out foam insulation and clean/dry the area between inner and outer hull. Typically, the refrigerator, and stairs must be removed to cut the flooring sufficiently to access the new tank. This is a good opportunity to run a condensate line from the refrigerator to the bilge pump area if needed. Like I said, there are many ways to accomplish the same task, you just need to spend an hour or two looking back through these threads.
 
gdavis67 said:
This has been "the summer of the water tank" in my opinion. Look back through this thread over the last couple of months and you will see many examples of this job. Poly tanks are less expensive, more options, and possibly more durable; aluminum tanks are also available. Drill access ports under the tank, dig out foam insulation and clean/dry the area between inner and outer hull. Typically, the refrigerator, and stairs must be removed to cut the flooring sufficiently to access the new tank. This is a good opportunity to run a condensate line from the refrigerator to the bilge pump area if needed. Like I said, there are many ways to accomplish the same task, you just need to spend an hour or two looking back through these threads.
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Good advise on the fridge condensate line. I did this about ten years ago when we addressed our leaking water tank issues.
 
gdavis67 said:
Are there any other 1990 390 owners out there that have toggle switches at the helm for your ignition switch? Mine has keyed switches at the panel in salon and toggles at the dash. They are OFF/ON/MOMENTARY ON type switch. I have one that is starting to go bad and need to replace it. I have searched the part number from the original switch and have not been able to find the correct replacement. I have tried digi-key and several other websites. This is a Carling switch, but no luck sourcing the correct switch.
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Are you sure its the switch and not the relay between the switch and the starter?
 
hey guys does any one know what the switch is by the water inlet and wash down faucet on a 86 express
 
Emie Boyer said:
hey guys does any one know what the switch is by the water inlet and wash down faucet on a 86 express
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My 86 doesn't have a switch in that area. Probably installed by a PO. Going to have to go trial and error to find out if it does anything. Could be some lights, cockpit speakers, etc.
 
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