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New owner of a 1980 Catalina 30

Dec 29, 2019
Catalina 30 Wilmington
Hello Everyone,

I am the happy new owner of a 1980 Catalina 30. with the 5411 Universal Diesel. The boat is in pretty good condition for the age and I have been spending time trying to learn the systems.

I just did my first test sail to head over to the pump out station and pump out the head. I do nhave a few questions about the head plumbing but I will get into that later. I have been reading all of the posts and comments in this group to get as much information as I can. Everything worked pretty well from my first test sail. After pumping out the head I sail out of LA harbor to raise the main and unfurl the jib. There was not wind so the sailing was calm.

Here's where I things went south. When I got back to the dock I made the mistake of turning the ignition key off before shutting down the engine. I had just done this on my previous boat and had to replace the alternator so I felt like an idiot and was extremely mad myself. So.. In testing the battery voltage under power heading back to my home dock, I only saw a reading on my voltmeter of 13. 1 or so. Previously While running the engine at the dock, I measured 14.6 +/-. Guess I need a new alternator. Again! I have the Motorola 55 amp alternator and of course that is no longer available. Does anyone know the replacement part number and source to find a new 55 amp alternator? Any feedback would be greatly appreciated.

Thank you,
Oct 22, 2014
CAL 35 Cruiser Portland OR, moored EVERETT WA
Welcome to the forum Kelly.

I would encourage you to check out MaineSails website. Marine How To - DIY for Boaters

Great source of electrical knowledge and alternators.

You can also take your alternator to a local electrical shop for testing/repair or replacement.

Best of luck with your new to you Catalina. We like pictures here so get a selfie of your boat and share.
May 20, 2016
Catalina 36 MK1 94 Everett, WA
Turning off the key shouldn’t kill the alternator. Turning off
the battery selector will if wired stock.

I personally like to wire alternator output to the house batteries and charge the start battery with an ACR. You can’t fry the alternator that way.

like John said take itto an alternator shop.
Feb 26, 2004
Catalina 34 224 Maple Bay, BC, Canada
When I got back to the dock I made the mistake of turning the ignition key off before shutting down the engine.
The ignition key only turns off the regulator.
If you were seeing lower voltage, was your house bank full? What rpms?
I don't think you have a problem. Test it again before you take off the alternator.
Do you have the wiring diagram? If not, let us know and we'll tell you where to find it.
Dec 29, 2019
Catalina 30 Wilmington
Thank you John, I will research Mainsail"s website. Thank you Leslie and Stu. I will retest the alternator. The batteries were bone dry so I filled with distilled water. They may be 2 far gone. date on batteries say 6/2015. It just seemed like I saw 14. 8 when the engine was running before.
Jan 19, 2010
Catalina 34 Casco Bay
I wouldn't through in the towel on that alternator.... If you didn't loose the regulator and you still suspect charging issues, I'd bring the alternator to automotive electric shop.. the type that rebuilds and repairs alternators. Could be a very simple repair or a total rebuild, but at least you'll have " your" alternator.
Dec 29, 2019
Catalina 30 Wilmington
Thanks sailme88. So I just ran the engine for 30 minutes. Checked voltage and it did come up to 13.49 in one and 13.15 on the other. Perhaps it would have rose higher had I let the engine run for an hour or so.
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Feb 26, 2004
Catalina 34 224 Maple Bay, BC, Canada
The batteries were bone dry so I filled with distilled water. They may be 2 far gone.
Ya think?!? :yikes:;)
I found that writing stuff down, in a log or even on a dated index card with engine hours makes a huge difference in helping to diagnose issues.
Some times it takes a few "things" to happen to begin to make a pattern, but unless I've recorded the data, my memory ain't what's gonna help me! :banghead:
Your batteries are toast.
Your alternator is most likely OK unless your batteries were so dried up the diodes in the alternator fried.
Things to consider, in order:
1. get new batteries
2. run engine and record alternator info (V, A if you can)
Good luck, keep us posted. :biggrin:

PS - Where is your voltmeter? Are you using the cockpit vm or a DVM?
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Mar 9, 2012
Catalina 30 PVR
I have a 1979 Catalina. Had issues. Then added a Blue Sea 7650 Add a Battery kit. That’ll fix all your start issues. Alternator is fine I believe. I’d get a set of 2 new batteries. We did the same. Totally changed the way we start and shut down. No issues at all. When adding the Blue Sea kit it will isolate the house batteries from the start. You can then run your house down and always have full power for start.

Also change all your lighting to LED. The old original boat lighting will drain your batteries fast when sailing. Our boats are probably very similar in mechanics etc. Anything i can help you on let me know.
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Jul 30, 2014
catalina 30 mkII Tall Rig bay city
I've had my Catalina 30 for 4 years now and have been turning the ignition off prior to pulling the lever out. I didn't know
it could hurt the alternator. It's been working just fine. I replaced my batteries two years ago after having them checked out
by our local Discount battery. Does anyone have advise as to the proper shut down procedure?
May 20, 2016
Catalina 36 MK1 94 Everett, WA
Turning the key won’t hurt the alternator diodes. Turning you a-both-b-off to off with a running engine WILL! Turning off the key just collapses the field current, powering off the Alternator.

I do leave key on and pull kill handle, just so I verify the oil pressure switch and alarms are still functional.

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Oct 11, 2019
Catalina 30TRBS New Bern
I pull the fuel cut off and allow the (diesel) engine to shut off before turning off the key. also, if you're going to idle the engine any length of time to charge batteries, put it under a load and give it some fuel (after you're sure you're tied up good. diesel engines don't like to run in neutral or idle for long...