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keysdisease2 · 10-07-2009, 23:55

I am considering replacing an original equipment Universal Atomic 4 on a 1971 36' sailboat with a diesel. Any thoughts?

**GordMay** · 11-07-2009, 04:27

Greetings and welcome aboard keysdisease.
What are your specific concerns about replacing the venerable Atomic Bomb?

keysdisease2 · 11-07-2009, 04:52

Does it make sense? Do I wait until it gives out or make the switch now? It may last forever. I prefer a diesel but also don't want to spend $10,000 or what ever it takes, for no reason.

**GordMay** · 11-07-2009, 06:21

Quote:

Originally Posted by keysdisease

...It may last forever. I prefer a diesel but also don't want to spend $10,000 or what ever it takes, for no reason.

I too much prefer diesel, but as you say, the A4 may last "forever".
I wouldn't "upgrade" my mono-hull boat to a catamaran (by adding a hull), and I wouldn't replace a well-functioning gas engine, just because.
In both cases, I'd change boats, if those "upgrades" were essential to me.
Consider a replacement, when the A4 looks to begin giving you trouble.

**David M** · 11-07-2009, 09:33

The answer really depends on how you plan on using your boat.

If what you are doing is going out on the weekend occasionally then I would not bother. If you are considering extended cruising then I would definitely replace the Atomic. If it is something in between then that is something your wallet will need to make a decision on.

You need to use a diesel quite a bit for it to start paying for itself over a gasoline engine.

There is also the safety factor of gas versus diesel.

You also need to consider the convenience factor of diesel in general being more readily available in some places overseas.

tex105 · 11-07-2009, 10:19

I went with Beta Marine and I love it. They have a drop in replacement for the A4.
Its Kabota based.

Tellie · 11-07-2009, 11:04

I prefer diesel over gas. But I'm of the old school "If it ain't broke"

Cheechako · 11-07-2009, 11:20

Universal Diesel is a direct replacement...

CapnTony · 11-07-2009, 11:22

The original owner of my boat replaced the Atomic 4 with a Universal M4-30 a few years before I bought it, and I'm glad he did.
I also think it will depend on your future plans for the boat.

keysdisease2 · 12-07-2009, 06:21

Thanks for all the information. Gordmay your analogy has me thinking - intereting. I am leaning toward replacement for the reasons outlined: safety, and some "extended" (beyond the Keys and US waters) cruising, plus the boat needs an entire upgrade. Best I can tell, nothing has been done since it was purchased in 1971 if it didn't break.

I need to check the "drop-in" replacements, thanks for that advice, and (dare I even ask about this?) rebuilt versus new.

svquest2 · 12-07-2009, 13:16

Your A-4 seems a little small for a 36' boat. If you just wanted to make a change to deisel without going to something around 40 HP this wouls probably be more power than your current A-4. Looks like a really good deal.

http://boatdiesel.com/Forums/Thread....hread_ID=29493

You should be able to get a rebuilt diesel between 30 and 50 HP for under %K and careful shopping might bring that down to 3.

Good luck

Joe S

zeehag · 12-07-2009, 14:16

Quote:

Originally Posted by Cheechako

Universal Diesel is a direct replacement...

universal and beta are kubota based and fit....goood luck...

redcobra · 12-07-2009, 16:54

Just repowered. the engine price was ok, but then..
New transmission as old was incompatible and drive ratio was different.
New fuel tank and sender (old tank had corrosion upon inspection).
New Racors
Rebuild V-drive
Different hp and rpm so.. new prop.
Rebuild stuffing box.
Oil change and all filters after 20 hours as per warranty spec.
New muffler system (old one too small including exhaust port on stern)
New engine required larger water intake so new through hull and raw water strainer.
If you do it your self.. crane rental, old engine disposal, etc. If done for you, about $2k-3K labor.
Lots of hoses, elbows, clamps, etc. etc.
IMHO total cost is about engine price X2.

zeehag · 12-07-2009, 18:19

Quote:

Originally Posted by redcobra

Just repowered. the engine price was ok, but then..
New transmission as old was incompatible and drive ratio was different.
New fuel tank and sender (old tank had corrosion upon inspection).
New Racors
Rebuild V-drive
Different hp and rpm so.. new prop.
Rebuild stuffing box.
Oil change and all filters after 20 hours as per warranty spec.
New muffler system (old one too small including exhaust port on stern)
New engine required larger water intake so new through hull and raw water strainer.
If you do it your self.. crane rental, old engine disposal, etc. If done for you, about $2k-3K labor.
Lots of hoses, elbows, clamps, etc. etc.
IMHO total cost is about engine price X2.

you got lucky--usually is more......
does it work nicely?? was it worth it??
mine was/is and i am not even done--got a huge haul out to handle when i get home....lol....