Prepping engine for launch

[DaveC426913]

So, I put the foot in a garbage can of water and started it up. BOOM! Started up no trouble.

I didn't do any winterizing at all. No fogging, no nothing. And it was c-o-o-o-ld!

So I'm really happy.

I ran it for 15 minutes or so, at low throttle then idle, just to be sure it's ready for launch day.

One question: it was blowing white fog out the exhaust the whole time. Not smoke, more like one of those bedroom humidifiers (I took a video). Is that something I should be concerned about?

It was a cool day - about 7C (45F), and drizzling all day, so I thought maybe it's just blowing off moisture and wold stop eventually.

[Jimmyt]

I'll take a stab at it.

If ambient temp was 45, and the air was at, or near saturation, I'm guessing you were seeing the water vapor in the exhaust condensing out of the exhaust gas mixture. One of the by-products of combustion is water... The conditions you describe would be ideal for condensing water vapor in exhaust gases.

I'm assuming your water pump was working, tattletale showing flow, etc., and you weren't hearing strange noises.

[DaveC426913]

I'll take a stab at it.

If ambient temp was 45, and the air was at, or near saturation, I'm guessing you were seeing the water vapor in the exhaust condensing out of the exhaust gas mixture. One of the by-products of combustion is water... The conditions you describe would be ideal for condensing water vapor in exhaust gases.

Cool. That was my guess, but I'm not handy that way.

I'm assuming your water pump was working, tattletale showing flow, etc., and you weren't hearing strange noises.

Yes, yes, and not any that weren't coming from me.

[Jimmyt]

What engine do you have?

[DaveC426913]

Honda BF-50

[Starscream]

If it was stored tilted up then white fog from the exhaust is normal for the first little while.

It could also be the environmental conditions as previously suggested. If you look at idling cars on some days there are clouds of visible white smoke and other days you see nothing from the same cars.

Check oil levels after each of your first couple of outings just to be sure.

I wouldn't worry. Now black smoke, that's a problem.

[Tomfoolery]

I consider that normal for the conditions; cold day, cold engine, low- or no-load running. The rule of thumb I've always gone by is white smoke is water, which can be water vapor from combustion, or coolant in the exhaust, blue smoke is excessive oil, and black smoke is excessive fuel.

My BF50 does the same thing running on muffs, by the way, and it's almost always cool or cold when I run it that way. Like when I winterize it in November, or vernal startup in May, which as you know, ain't usually very warm around here. Never noticed anything on hot days, with the boat in the water. And it's still running strong, since 1999.

[seahouse]

Yep, the reasons mentioned above, condensation of combustion-produced water when it hits the cold air, just like your car in winter (it is worse until combustion becomes more complete as the engine warms.)

To cool the exhaust gasses and exhaust metal components, and to attenuate noise, water is mixed in a chamber that is part of the exhaust system. The walls of the chamber are hot, so before it exits the exhaust opening (through the the prop hub or other dedicated ports) some of the water turns to steam as it flows over them. This adds to the amount of steam that you would see from combustion alone.

You will also notice that the amount of steam produced changes with the various operating parameters of the engine, like rpm, engine load, ambient temperature, etc.

[Tomfoolery]

You will also notice that the amount of steam produced changes with the various operating parameters of the engine, like rpm, engine load, ambient temperature, etc.

This ^ plus when the engine is driving a prop in forward at any kind of speed, the cooling water and exhaust is pulled through the prop and not much (if anything) comes through that relief port. AFAIK, that port is just there to unload the exhaust backpressure when the boat is idling in neutral, with the prop under water.

[DaveC426913]

You will also notice that the amount of steam produced changes with the various operating parameters of the engine, like rpm, engine load, ambient temperature, etc.

This ^ plus when the engine is driving a prop in forward at any kind of speed, the cooling water and exhaust is pulled through the prop and not much (if anything) comes through that relief port. AFAIK, that port is just there to unload the exhaust backpressure when the boat is idling in neutral, with the prop under water.

Granted. Although I do not notice this when idling at my slip. Though perhaps it's more because I'm not in as prime a position for observation.

[Tomfoolery]

You will also notice that the amount of steam produced changes with the various operating parameters of the engine, like rpm, engine load, ambient temperature, etc.

This ^ plus when the engine is driving a prop in forward at any kind of speed, the cooling water and exhaust is pulled through the prop and not much (if anything) comes through that relief port. AFAIK, that port is just there to unload the exhaust backpressure when the boat is idling in neutral, with the prop under water.

Granted. Although I do not notice this when idling at my slip. Though perhaps it's more because I'm not in as prime a position for observation.

I was almost going to say something along those lines, but seahouse already mentioned ambient temperature. Between warm weather in the slip, and not really looking for it when actually on the boat prepping to depart and not being in a great position to even notice it, I suspect one or both is the reason.

[DaveC426913]

Thanks guys. you have allayed my concerns that a complete lack of winterizing (including not fogging) has done bad things to my engine.

(Although maybe I should check the oil.)

[seahouse]

Yeah, because of the angle and height it's far less visible in a Mac. In the olden days before the side-firing "P" stream was common on outboards it was part of the water pump check procedure on start up to swing the wheel hard over one way to more easily see sputtering water exiting the above-the-water-level exhaust port.