Leaving outboards outdoors

[Micro]

I have a 15' jon boat that I keep outside 24-7.  It's well covered with a cover that hangs almost to the ground on both sides and in the back.  

Up until this summer I've had a 9.9 hp Mercury that I used on it.  I kept that motor in the garage on an outboard cart.  It was light enough that putting it on and taking it off for each trip was no problem.   But now I've up'd to a 15 hp Merc and it is way heavier.  Putting it on and taking it off is a LOT more trouble.  

I'd like to leave it on my boat through the season, storing it in the garage only during winter.  It would stay well covered and would not be exposed to direct sunlight or elements - except summer heat, which I can't do anything about.  

Are there any special precautions or measures I need to take?  I know engines on big boats stay out all the time.  Just wondering if there is anything I need to do or haven't thought of.

Thanks.

[The Rooster]

My first boat I had a 15 HP Mercury, a 91 model motor.  I left it on the boat all year long except for winter and then I stored it inside.  I had it for 3 years with no problems at all.

[Micro]

Did you do anything special to it?

[The Rooster]

No, all I ever did was use it normally running it while at the lake. When I came home after fishing I just parked it until next time I took it out again. Might be 24 hours later or a couple of weeks. Sometimes during that time it wasn't even covered up unless I thought it might rain. During the winter I put some Stabil fuel stabilizer in the gas to winterize it and ran the motor for a few minutes, then drained the lower unit, and then removed it from the boat for storage indoors. I did not fog the engine as some suggest but I never had any problems at all with springtime startup. When I sold the boat the motor still ran like new. That was almost 10 years ago now and the guy I sold it to still has it and it runs fine now.

[TruckMechanic]

I'm the same as roostertails, I just take mine off in the winter and store inside. I put the bolts back in the holes to keep water from entering my transom.

[HPBB]

I take it your 15 is a 4 stroke, since a 9.9 and a 15 are the same motor and wieght. as for leaving it on the boat out side. there is nothing wrong with that at all. on the bigger boats you can't take the motor off and how many do you see outside all year. as long as you winterize it before the long nap each year it will be fine. I have two boats and 3 outboards and all sit out 24/7/365 never have any problems with them sitting outside.one has a 75Hp and 6hp kicker and the other is a 15hp merc.  make sure you keep the motor trimmed down so water doesn't lay in it and it can drain compleatly.

[CGH]

I have a 25hp Evinrude that weighs around 125, 135 and it is carried in and out of the house with every use. I would never leave a small Outboard out side. Leave it outside long enough and some varmit will come alone and he or she will take it and keep it in their home ;D

[Micro]

I take it your 15 is a 4 stroke, since a 9.9 and a 15 are the same motor and wieght.

That used to be the case, but not anymore.  Not only is the 15 bigger, the 9.9 was 85lbs and the 15 is 130lbs.  

[Wayne P.]

In looking at the Mercury website, it seems that they do not make any more small two stroke motors including the 9.9. So if you have a new manfactured (since Jan 2007) 15, it is a 4-stroke.

[HPBB]

that is what I was asking if it was a 4 stroke. and according to their web site the 15 is 111lbs not 130. but that is nit picking. but either way it will be fine left outside on your boat. yes use a lock so no one walks away with it. I would buy a motor cover for it if its new and you want it to look new.

do you see a notice able increase in speed.?I am asking because that 5hp difference and either 26lbs, or as you stated 45lbs more weight would seem to negate the extra 5hp.

I know when I run my 15 merc (2 stroke) next to a 9.9 merc ( 2 stroke) there is only a few mph difference and they weigh the same

[Ann-Marie]

Make sure to put some insect screening mesh in any air inlet ports on the engine.  Mud daubing wasps just about ruined my 40 HP Honda 4 stroke.  The honeycomb air filter in it made a perfect condominium and late comers filled up all the spaces between the cooling fins.  I had to dismantle half the engine to clean it up.