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What is the best way to run the engine on the hard? I want to be sure enough water is getting to the engine.
 

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Just put the water intake hose in a bucket of water, fire up the engine, and keep the bucket filled. Have someone check the exhaust outlet to be sure there is water being emitted, and keep an eye on the engine heat gauge. I did this today, everything worked fine, the engine fired right up after sitting for six months. Life is good!

Good luck,

Gary :cool:
 

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What engine: inboard fresh water cooled, raw water cooled or outboard?

Gary's plan is good for the first two. Never pressurize the water going into an inboard, allow it to draw out of a container and have a hose refilling the container. Often, you will need to attach a new intake hose, in order to reach the bucket. The bucket is best inside the boat, but it can get messy. The motor's water pump is designed to lift water from the thru hull. A hose all the way to the ground could be more than she can handle, so the container may either need to be lifted or inside the boat.

Outboards can use a hose attached to a device that looks like ear muffs squeezed around the intake on the lower unit. Some outboards have a dedicated attachment for a garden hose to flush/cool.
 

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What Gary and Minnewaska say. If the engine uses a closed-loop cooling system with a heat exchanger you can run a diesel for a short period without providing raw water to the heat exchanger. I've done this many times for less than a minute. In fact, when I took a diesel course from Mack Boring they would run the engines for many minutes unconnected to raw water.

If all you're doing is firing the engine after a layup just to make sure it's running, then this works OK. Of course if you run into issues and need to run it longer, then providing water Gary's way is essential.

NOTe: If you're going to do this you must remove the raw water impeller on the intake water pump, or otherwise stop it from running if it is belt-driven. The impeller will die a painful death if run dry.
 

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What Gary and Minnewaska say. If the engine uses a closed-loop cooling system with a heat exchanger you can run a diesel for a short period without providing raw water to the heat exchanger. I've done this many times for less than a minute. In fact, when I took a diesel course from Mack Boring they would run the engines for many minutes unconnected to raw water.

If all you're doing is firing the engine after a layup just to make sure it's running, then this works OK. Of course if you run into issues and need to run it longer, then providing water Gary's way is essential.

NOTe: If you're going to do this you must remove the raw water impeller on the intake water pump, or otherwise stop it from running if it is belt-driven. The impeller will die a painful death if run dry.
Hi Mike, replying to this now-old post but wanted to be clear on this before I start up the deisel on the hard for the first time. Are you saying it is ok to run It for less than a minute without removing the impeller, OR, no matter what, one needs to remove it or stop it from running?
 

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My procedure is to first start the engine in the spring with the hose out of the water bucket. This is in case it takes s bit of time to first get it going after changing filters, etc. Don't want to chance filling the exhaust with water. As soon as it fires, I stop the engine, put the water inlet hose in the bucket, and restart the engine.

A short run of 10 seconds or so without water is very unlikely to damage the pump impeller. But I want a test run of 5 minutes at least to make sure everything looks good before relying on the engine to take me from the launch ramp to my mooring.
 

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Running an impeller dry is simply a crap shoot. Is it new, has it developed some early cracks that haven't let go, etc? You just can't know. Odds are, an impeller in good shape would be fine. I've had enough of them let go unexpectedly over the years, that I just don't trust them.

In fact, just this commissioning season, I started my generator for the first time, while in the water. I typically leave last year's impeller in the engine, over the winter. I start it once, to purge the antifreeze and warm it up for an oil change, then I also replace the impeller with new. This year, for the first time ever, the one year old generator impeller threw a couple of blades and I had to go fish them out of the heat exchanger. Tripled the job.

Personally, I wouldn't trust the vibration, from running the engine, while on stands anyway. Why not just wait until in the water. If one was going to run it truly dry, perhaps dosing it with glycerin or dishsoap would keep it lubricated long enough. Even a closed thru-hull doesn't really mean it's fully dry, it's just not drawing more water.
 

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Hi Mike, replying to this now-old post but wanted to be clear on this before I start up the deisel on the hard for the first time. Are you saying it is ok to run It for less than a minute without removing the impeller, OR, no matter what, one needs to remove it or stop it from running?
If you want to be safe, removing the impeller is the best approach. But I don't, and I've never had the impeller be damaged (to my knowledge). I start the engine on the hard just to make sure it's going to run, and also to remove the antifreeze before going back in the water. It usually takes about 20-30 seconds I say.
 

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By the way, they sell run-dry impellers. I always thought it was probably a scam. Then once, on an unfamiliar engine, I accidentally ran it up to temp to change the oil, with the thru-hull closed. It's internal temp sensor shut it down about 10-15 minutes in. I immediately knew what I had done wrong! Felt like an idiot, but there are only two kinds of sailors "those who have" and "those who will". Just a matter of time.

Before starting it up again, I obviously let it cool down, but also opened up the impeller to change it. The run-dry looked pretty battered and worn, but none of the blades separated, after that much time on a closed thru-hull. I was impressed. I don't think they make them for all engines/pumps and they're pricey.
 
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