Atomic 4 vs. diesel ?

[fdr14127]

Originally Posted by GusC

Sounds, great. I will avoid gasoline inboards

Thanks everyone!

And buy a boat with propane stove.....

[waterman46]

Originally Posted by roland stockham

Gas engines rely on an electrically generated spark to keep running diesels do not. In the marine environment this adds significant issues to reliability

That spark, combined with gas vapors is extremely dangerous. We had a Cal29 for many yeas. Nobody else mentioned it, but my greatest problem was not with the ignition system (that was a simple old-school points and distributor system, nothing that couldn't be diagnosed in a minute).

But I grew very tired of fixing the float valve in the carburetor. Either would stick shut or stick open. Sticking open causes flooding of gas that more than once resulted in gasoline on the outside of the engine. Caught it by the smell and shut down before it became a lake of gas in the pan under the engine.

So, like a small gas outboard, you may end up fiddling with the float valve adjustment a lot. Be careful.

We did have a normal fuel filter in the line. But our gas tank had become rusted on the inside, where we couldn't see it of course. So perhaps that was part of the problem.
We eventually replaced that steel gas tank with a new aluminum one. This was a Cal 29, and access to swap the tank was fairly easy.

[Atlanticsailing]

I've recently retired from over 50 years as a professional charter boat operator and captain, owning various boats from 18' mahogany runabouts, to mid-sized modern sailing vessels, to 70+ sailing vessels.

Without doubt, no hesitation, I recommend go with an inboard diesel. Diesel engines are far simpler, safer and fuel efficient than gas engines. Atomic 4 engines are almost cult-like antiques subject to all kinds of additional maintenance and break downs than a diesel. Further, Lake Michigan is not the body of water for a week-long cruise with an outboard motor.
Best luck

Patrick

[dfelsent]

I had an A4 powered boat for over a decade. That f***ng float valve leaking gas. Despite clean filtered fuel. Can you say carb cleaning at sea and bilge with gas in it too? Nauseating.
And it was raw water cooled. Big project cleaning the passages. Not all are raw water cooled though.
Points and condenser convention ignition gave me no problems.
Transmission was solid.

I like diesel. Much more.
Although I could, and did have to, hand crank the A4.

[TideTime]

I suspect that 1978 Catalina 30 can be purchased for considerably less than the $8,995 asking price, and while you would definitely want an inboard engine in a boat the size of the Catalina 30, I concur wholeheartedly with LittleWing77 with respect to the Atomic 4 motor and would avoid it "like the plague". You should be able to locate plenty of Catalinas in the 27-30 foot range with Yanmar diesel inboard motors.

[Sailor George]

Gus, I have a 1980 Mariner 36 with a 5432 Universal engine. It’s still going strong! It’s built around a Kubota tractor engine, which you can parts for at a Kubota dealer. I’m pretty sure they were used in the older Catalinas. You may want to check out Good Old Boat magazine’s boat for sale section. I see a lot of boats in the range you are looking for listed in your area. Good luck.

[guyrj33]

First the whole diesel vs. gas thing.
Imagine you own a boat yard and someone comes in with a gas engine sailboat with engine issues. Do you fix the gas engine for a couple of hundred bucks or do you spin a tale about how unsafe gas is and up sell a 10k diesel?
For day sailing and short trips in and out of the harbor a gas engine is superior and a diesel is likely to be harmed by that usage pattern.
For long trips a diesel is superior, better fuel milage and diesels like to be run at a high load.
Diesels run excess fuel past the fuel injectors and return that extra fuel to the fuel tank effectively warming the diesel fuel tank. Why does this matter? Imagine you motor for the last 30 minutes of your day trip and then anchor or dock. It's the end of the day, the sun is setting and the air is cooling, so is your fuel tank and as it cools it pulls in the cool moist air outside of the boat. That moisture condenses inside your fuel tank, and it it's a diesel tank water encourages slime growth.

Now should you buy a boat with an Atomic 4 in it?
Yes if you feel somewhat comfortable working on a simple gas engine and yes if you can remember to turn on your bilge blower and smell test for gas.

Should you buy a boat with a diesel?
Yes if stories about the danger of gasoline scare you, yes if you're willing to pay more to purchase the boat, yes if you can afford to pay more for engine parts.
Yes is you truly need much better fuel milage.

In either case there will be lots to learn about your new boat and its' engine.

[Lake-Effect]

I would be a bit concerned about getting a reliable inboard, gas OR diesel, in a <$10k boat. it might be possible, but...when that inboard starts needing $2k+ of repairs, you'll find out why there are so many smaller boats with a dead inboard and a running outboard.

I wouldn't be that afraid of an outboard on a boat that's 27 ft or less, if your sailing skills are good, and you pick your weather window with care.

[MicHughV]

if you plan on going with a gas engine...be it an Atomic 4 or outboard....

be aware of this one VERY important thing !!

most modern gas contains ethanol.....ethanol is widely recognized as the # 1 problem on gasoline engines.....it will eat anything and everything plastic or rubber..the modern car mostly uses all metal gas lines now due to this issue...

most marina's which sell gasoline for outboards, will have a non-ethanol brand of gas, some gas stations also carry it...but very few...
non-ethanol gas is more expensive than regular gas, by almost double...our local marina charges about $4/gallon..despite the extra cost, don't use anything but this for your boat gas engine....ever !!

[LittleWing77]

Originally Posted by MicHughV

if you plan on going with a gas engine...be it an Atomic 4 or outboard....

be aware of this one VERY important thing !!

most modern gas contains ethanol.....ethanol is widely recognized as the # 1 problem on gasoline engines.....it will eat anything and everything plastic or rubber..the modern car mostly uses all metal gas lines now due to this issue...

most marina's which sell gasoline for outboards, will have a non-ethanol brand of gas, some gas stations also carry it...but very few...
non-ethanol gas is more expensive than regular gas, by almost double...our local marina charges about $4/gallon..despite the extra cost, don't use anything but this for your boat gas engine....ever !!

Didn't know this additional info about ethanol additive in gasoline.

Thanks, McHugh!

LittleWing77

[Jim Cate]

most modern gas contains ethanol.....ethanol is widely recognized as the # 1 problem on gasoline engines.....it will eat anything and everything plastic or rubber..

How odd, then, that here in Oz Methylated Spirit (ethanol with a small amount of methanol added to make it undrinkable) is sold and stored in... plastic bottles.

The larger issue with alcohol in petrol is water absorbtion leading to formation of stuff that clogs small passages. The "eating" problems have largely been solved by the folks who make gaskets and seals. Could be a problem with an older engine, true, but compared to the other problems mentioned in the many posts above, likely not a biggie!

Jim

Jim

[mvweebles]

I dunno. Not really a gas vs diesel discussion but an Atomic 4 vs Universal 5411 2 cylinder raw water cooled diesel, the alternative available in 1978 when this boat was splashed

I'm not sure which one is Queen of the Pigs. Neither are great engines.

Peter

[AndyEss]

My first boat, a 26ft wooden sloop I bought in 1976, had a Graymarine flathead 4 in it, complete with updraft carburator. I learned to be an engine mechanic on that simple spark controlled engine. I was out of Chicago on Lake Michigan too.
If this is your first boat, and you want to learn how to fix all your own systems, and you promise to religiously use the bilge blower and smell the exhaust of the blower for gasoline fumes, a heavily discounted gasoline burner might be OK for several years.
If you aren’t planning on getting your hands dirty, an inboard diesel, preferably based on a small tractor engine, is probably the way to go. For daysailing and a small boat, an outboard will be even simpler.
Gasoline is dangerous in boats if it is allowed to leak. Fumes will build up in the bilges, just waiting for an ignition source. Automobiles are open on the bottom, and so aren’t subject much to fume build-up
concerns.

[GusC]

I can’t thank you enough for your comments. I am relatively handy, engineer-oriented to an extent, but have no experience working on engines. I am willing and able to learn, but not really excited to having to do it

[dfelsent]

I’ll go back to my previous A4 post. That thing was a pain.
But so simple to work on.
Brainless for a moderate gear head.

But thinking back the two diesels I’ve run long term since then have been more about regular maintenance and less about fixing what just broke.

I am talking about 2000-3500 hours on all three engines.

The atomic 4 design goes back 75 years or so. Most of our diesels go back only 10-50 years. So not so different.

It’s pick your poison. But dang, I’m glad I am not running an A4 on today’s fuel.

Actually running would be fine. It’s storing for a period of time that is trouble.
And I used to make sure I shut off my fuel and ran the carburetor dry every fall as part of winterization.