Battery Expectations - 32V bank

Rolling the motors over with the shutdown pressed down for 60 seconds is a very long time, too long, and most battery banks won't do that and also it's very hard on your starter. The reason people do this is to get oil circulating through the motor before it fires. However, most people do it for 10 seconds. And, if you're running the engines every 2 weeks, it's probably a waste of time.

First of all, the 8v195 is not a heavy duty battery. Fine for quick starting purposes. 60 seconds is ridiculous, I have to believe he said six seconds. That's all you need at best. The Hatteras manual will say "several revolutons". Me I use the count of three and everyone is happy (Hatteras 56MY with 8v92TTi's). If you are going to use these engines in cooler weather, invest in block heaters, cheap and wonderful for many reasons.

On my boat, the starboard bank just starts that engine and powers the system monitor. I do have 8v195s over there which I put in a pinch, and they turn the engine well. But I know I am cheating with those. Over on the port is the port bank which starts that engine and serves as the house bank. There, I am doing the right thing and have the Rolls 8HHG25's, which weigh over 30 pounds more than the 195's. The Deka 819 is the basic spec. If you use 195's for your house bank you will be ripping through them on a regular basis.. high cost of ownership. When mine burn up on the starboard side, and I am in a place where I have time and a choice, I will go with 819's or the Roll's equivalent, which is one step down from the 8HHG25's.

Disclaimer: I am an electrician and not a diesel mechanic and I have a passing acquaintance with Detroit engines.

That said; not only is a 60 second starting procedure damaging to the starter motor, the batteries and the interconnecting conductors, it is also very possible to severely damage the engine.

When a diesel is operating, the raw water pump is bringing seawater into the engine's raw water cooling system. When the warmed raw water has completed its circuit, it is expelled from the engine at the diesel exhaust elbow where it is mixed with the hot exhaust gas, cools and quiets the exhaust gas and is then encouraged overboard by the exhaust gas.

When cranking the diesel with the kill switch depressed, the raw water pump is operating and the raw water is circulating but there is no exhaust gas to encourage it to leave the vessel. When the cranking is stopped and the engine is not running, the raw water may pool in the exhaust manifold and then enter the engine via any open or partially open cylinder exhaust valves, damaging the engine.

Again, I have a passing acquaintance with Detroit's but every generator manufacture has a warning in his operator's manual against extended cranking of the engine. In the case of the genset, the remedy if extended (> 10 seconds) is required is to close the raw water seacock until the engine starts.

Another reason some people hold the stop in to start these and other DDA's is due to low compression. By holding the stop, the engine will spin just a little faster building more heat and thus the fuel will ignite. Naturals should start very easy, even in cold climates. Have a technician run a compression test or pull down some hand hole covers and inspect the top rings for wear.

How's that work?

I believe, he means by decompressing the cylinders, the starter would have an easier job. Then letting the button go and the engine would start immediately. Thats the way, the very old diesel engines (like the hand cranked old agricultural tractors and early single cylinder long stroke diesel) were started.

Then it does not make sense at all, other than a dry crank. It was the only reason, I could imagine.

The addage is that you're turning the motor over at 200rpms or so with the starter without the engine firing, that circulates some oil through the passages and block (prelubes) it before you have the motor turning at 600rpms and creating heat before lubrication has gotten there. Some Bertram SF I've run even had a 3 way toggle for the start button, middle being off, up labeled start, and down labeled "prelube" where it would turn the motor over without allowing it to fire.

I never said "Holding the stop button down to build up pressure sounds flaky also."
It basically makes it easier on the batteries, and they do in fact spin a little faster. Try it with a photo tach. If your not injecting fuel the cylinder is not being impeded. If your engine is weak or low on compression by not allowing the rack to be at full fuel while starting is helpful. Does anyone remember detroits using starting aids, and I don't mean either. Why do you think DDEC engines are capable of 1/2 engine start, or why does MAN v-8 start on 4 cylinders.

The original owner's manual that came with my Hatteras specifically instructs to hold the stop button down "for several revolutions" before releasing, engines are 8v92ti's; but what would they know? I do it for about a two count. The engines will start immediately if I don't do this and sometimes I don't if they are warm. Otherwise, why not just follow directions?