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Broad Reachin'
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Discussion Starter · #1 ·
Forgive my naive question, but can an Atomic 4 by started while a boat is on the hard? I'm assuming they are water cooled, which presents a problem while on the hard. But is there a method of attaching a water hose to run test it out?

I'm considering the purchase of a used boat with an A4 that hasn't been run in 3-4 years. Among many other potential issues, I'm concerned about the A4's condition. Before I spend the money on launching/sea trialing the boat, I'd love to know if the A4 runs.
 

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not Sully or Dandelion
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195 Posts
I have done it many times. Remove the hose that goes to the threw hull, put the hose into a 5 gal bucket of water. The bucket should be down at about the same level as the engine. And keep the bucket from going empty by constantly feeding fresh water into it.
 

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Sea Dweeb
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Here is a link to a PDF copy of the manual
http://www.cncphotoalbum.com/atomic4manual/a4manual.htm

Is you engine raw water cooled or Fresh water cooled? The procedure is slightly differnet.

If fresh water cooled:
1. Close raw water thru-hull valve
2. Check oil
3. Check coolant in heat exchanger (1" or so below filler neck)
4. Run a hose from the raw water "T" valve into a bucket of fresh water
5. Check that the raw water "T" valve to the bucket is closed
6. start engine
7. check oil pressure
8. When the 5 gallon bucket empties (in about a minute) shut down the engine.
 

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Very important! Do not crank the engine with the hose in the bucket of water or you risk getting water in places it shouldn't be (the cylinders, specifically). When the engine catches, THEN place the hose into the bucket.

I would also suggest checking the condition of the impeller first (among other things) -- it if hasn't been started in 3-4 years, it could be in pretty bad shape. If a vane or a piece breaks off and gets lodged in the cooling system, you'll have some work ahead of you.
 

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not Sully or Dandelion
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Very important! Do not crank the engine with the hose in the bucket of water or you risk getting water in places it shouldn't be (the cylinders, specifically). When the engine catches, THEN place the hose into the bucket.
That indeed is good advice.
And I would not put the engine in gear. Make sure it is in neutral.
 

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Very important! Do not crank the engine with the hose in the bucket of water or you risk getting water in places it shouldn't be (the cylinders, specifically). When the engine catches, THEN place the hose into the bucket.
Why would this cause any problem? When the boat is in the water, isn't that like having the hose in the bucket?

How does the water get into the cylinders from the cooling system?
 

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not Sully or Dandelion
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Why would this cause any problem? When the boat is in the water, isn't that like having the hose in the bucket?

How does the water get into the cylinders from the cooling system?
Here is a quote from Don Moyer. Found here:

Much much water in Atomic 4 [Archive] - Moyer Marine Atomic 4 Community

1) The most common way for water to get into the cylinders of an Atomic 4 is for cooling water to back up within the exhaust system by over-cranking the engine with the raw water through-hull open. Without the engine running and producing exhaust pressure to move the cooling water out through the exhaust system, water will continue to collect within the system until it reaches a level that enables it to flow back into the manifold. From there, the water has a direct pathway back into the combustion chambers.
 

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Why would this cause any problem? When the boat is in the water, isn't that like having the hose in the bucket?

How does the water get into the cylinders from the cooling system?
MorganPaul beat me to it. When the boat is in the water, the best practice, especially if some time has elapsed since the engine was last started or if it is likely to crank for more than a few seconds before catching, is to leave the thru-hull CLOSED while you crank the engine and OPEN it after it catches. That way you're sure not to overload the exhaust system with water and then the cylinders, etc.

It goes without saying that you should close the raw water thru hull (and any others) when you leave the boat. Some people put little reminders (a label or even hanging the key on the valve itself) to remind them to open it after it's started.

BTW, Pretzel, welcome to Sailnet.
 

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Why would this cause any problem? When the boat is in the water, isn't that like having the hose in the bucket?

How does the water get into the cylinders from the cooling system?
It, or rather the antifreeze/fresh water mixture, will siphon back into the valve chambers if you crank without the engine catching (see above). The A4 can run "dry" for a couple of minutes from cold if you are just attempting to start it. You can even plan for this.

When you replace the impeller (and after four years on the hard, you WILL want to do this...and get a circ-clip pliers to make life easier), you will want to check for leakage at the pump body-to-block gasket, and you will need to find "pump grease", a waxy sort of hard grease like beeswax, to put in the pump shaft lube port (the little screw-on cap you periodically tighten). If you don't have this, a thick blob of lithium grease will do, but won't last as long.

When you fit the new impeller, grease that entire area with lithium grease as it will keep the new impeller nice and slippy for the short period you intend to run it dry, as it is the water itself that keeps the vanes supple.

Start the engine (you should already have put in new spark plugs, check the spark wires, checked the coil and distributor connections and made sure the batteries are serviced and charged and that you've got a new alt. belt on that is properly tensioned. You also better hope that the fuel system was COMPLETELY drained and the carb was fogged or otherwise cleaned and that the gas is completely fresh and the tank vent isn't a spider condo. But I digress.

Once the engine's running, in neutral, watch the gauges to see if the alt is charging and the oil (which should be fresh and "pre-cranked" by hand into the cylinders) is at 25-40 PSI. Watch the temp gauge. It can go from 100-150F without harm, but that could take five minutes in neutral, so you have plenty of time to drop a hose into a bucket once you've got it running. It helps to have a second person to handle the bucket to catch the old antifreeze, to read the gauges, and to stop or start the engine while you run this checklist (and it's only partial).

My point is that there are several ways in which an Atomic 4 won't start or will look like junk when it isn't...someone just forgot to do the right thing.
 

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Broad Reachin'
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Discussion Starter · #11 ·
Wow, you've just made me more apprehensive then ever to even consider this boat with an A4 that's been sitting for a few years. Thanks Val!

Seriously, thanks for the info. Sounds like a lot of work for me as a potential buyer just to see if she'll fire up.
 

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1975 Newport 28
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Ah, but those old A4s will give you years of life if you take care of them.

What's been written so far might seem arcane and complex, but if you look the comments over you'll realize that the A4 is a very basic gasoline engine that even a weekend mechanic can maintain. If you've ever tuned up a '70s or earlier American car engine the A4 will look very familiar to you.

Would you attempt to start any engine that's been sitting for a few years without making sure it had good oil and gas, good wires and a good battery?

If all you really want to do is see if the engine will start, don't even worry about the impeller. If it starts you'll know right away and the first two minutes running dry won't hurt a thing. Replacing an impeller on an A4 is a 15 minute job anyway, depending on your access.

Don't be scared off by the A4. Do you know anything more about a diesel? :D
 

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Wow, you've just made me more apprehensive then ever to even consider this boat with an A4 that's been sitting for a few years. Thanks Val!

Seriously, thanks for the info. Sounds like a lot of work for me as a potential buyer just to see if she'll fire up.
If you consider a gas driven engine - the A4 is the way to go. If you are even apprehensive / mechanically challenged - go diesel. I have done both and the diesel is way more forgiving IMHO...and the maintenance is cookie cutter even for someone not mechanically inclined. My 2 cents (and glad I own a Yanmar diesel)
 

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The A4 is such an appropriate engine for sailboats under 35 that there's a guy making new ones. If you, like most sailors, motor until you get head to wind for 10 minutes and then switch off, and then motor 15 minutes to your mooring or dock, then the A4 is more appropriate than a diesel in many ways.
 
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