Boating in extreme temperatures

[Keepi time]

Getting ready for a small vacation on the NC coast. Temps are going to be in the 100's this weekend. Question is,..is there any precautions to take running my 90 hp Johnson in temps like this. I'm all ears fellow boaters! Thanks!!

 

[MWG2600]

Re: Boating in extreme temperatures

nothing different than normal!

 

[Philster]

Re: Boating in extreme temperatures

Hot, humid weather = less HP from an engine.

Personally, this is not the time to run an O/B at WOT. That's it. Seriously, in extreme heat w/ extreme humidity, 99% of everything you do will be the same, but given the power loss and chance for a lean condition at full throttle if you really stay on it (debate ensues), just go boating.

Worry about yourself overheating.

 

[Home Cookin']

Re: Boating in extreme temperatures

not as long as you have enough PBR iced down.

I think Phil's comments pertain more to the racing side of things. a 90 OMC is a work horse. They are used hard all over the tropics. your water temps are in the 80/s. Your boat won't know the difference; if there is a performance factor you won't know the difference. Have fun and don't sweat it.

 

[coastalrichard]

Re: Boating in extreme temperatures

Heck, that motor doesn't know where it is but those on board will want a good bimini top and a big cooler with lots of ice, water and "other" liquid refreshments

 

[H20Rat]

Re: Boating in extreme temperatures

Hot, humid weather = less HP from an engine.

Personally, this is not the time to run an O/B at WOT. That's it. Seriously, in extreme heat w/ extreme humidity, 99% of everything you do will be the same, but given the power loss and chance for a lean condition at full throttle if you really stay on it (debate ensues), just go boating.

nope...

most/all outboard carbs are not temperature compensating. They are set for ideal conditions around 60 degrees or so. If you get above that, the amount of fuel going in the carb stays the same, but the density of the air drops. You run richer than normal. And on the other end of the spectrum, if you boat in cold enough weather, WOT has the potential to grenade your engine for you. Again, same amount of fuel, but the nice cold air is dense. Dense air = more oxygen molecules, but the same fuel.

Talk to some die hard snowmobilers... Those engines are very picky about temperature and altitude, since they are tuned much closer to the ragged edge. A 20 degree drop in temperature has pushed more than one finely tuned engine into lean [grenade] territory.

 

[jkust]

Re: Boating in extreme temperatures

nope...


Talk to some die hard snowmobilers... Those engines are very picky about temperature and altitude, since they are tuned much closer to the ragged edge. A 20 degree drop in temperature has pushed more than one finely tuned engine into lean [grenade] territory.

This is why I like my EFI sleds over my carbed ones. EFI is heads and shoulders and whatever is above that better.

 

[QC]

Re: Boating in extreme temperatures

I moved the Johnny-Rude forum. Seems better here as it is a technical engine discussion.

 

[TurboM700]

Re: Boating in extreme temperatures

What other have said. Warm/ more humid air will make the motor run rich. From someone who runs 2-stroke turbo snowmobiles its those very cold days you need to be carefully on any sled. Weather is EFI or Carb same goes for outboards. I know my Merc 135 black max hates the warm humidy days but loves the cold fall mornings when I leave to go fishing. That becuase its runing super rich when its that warm out.

To answer the ops question the biggest thing you need to worry about is your family and your self drink lots of water but I'm guessing you already know this.

 

[archcycle]

Re: Boating in extreme temperatures

You can be confident that Johnson designed your motor to run all over the globe all year round.

 

[archcycle]

Re: Boating in extreme temperatures

You'd think humidity several inches above a large standing body of water would be relatively stable anyway..

 

[dingbat]

Re: Boating in extreme temperatures

http://www.engineeringtoolbox.com/ai...ity-d_771.html[/url]

Your link is bad. If what you say is true, the engineering toolbox has a bit of contradictory information.

Water Vapor
Water vapor is almost always presence in the air. The content may vary and the maximum amount possible of water vapor in dry air depends on the temperature of the air.
Water vapor - H2O - is composed of one Oxygen atom and two Hydrogen atoms. Hydrogen is the lightest element at 1 atomic unit while Oxygen is 16 atomic units. Thus the water vapor atom has an atomic mass of 18 atomic units. With 18 atomic units water vapor is lighter than diatomic Oxygen with 32 units and diatomic Nitrogen with 28 units.
? Note! Water vapor in air will replace other gases and reduce the total density of the mixture. Dry air is more dense than humid air!

http://www.engineeringtoolbox.com/molecular-mass-air-d_679.html

 

[Keepi time]

Re: Boating in extreme temperatures

Thanks for the technical debauchery. It's running great so far.