Cold weather running/Testing

ShoestringMariner

Lieutenant Commander
Joined
Apr 18, 2015
Messages
1,560
I’m like a kid who got a bike for Christmas...my new to me boat is in the driveway and I just want to test it with earmuffs. It’s been too cold, windy and snowy to do anything outside and all I can do is look at if from out the window.

the weather is clearing but will still have a few nights below freezing. Would it be a bad idea to test run this thing until the weather stays above freezing? It’s only supposed to be just a few degrees below freezing at nights but I’m concerned with undrained water in the system. (It’s an old merc 650)

or do outboards typically drain right out when dry stored?
 

jbuote

Lieutenant Junior Grade
Joined
Aug 17, 2016
Messages
1,001
Not a pro, but most outboards will drain on their own when tilted all the way down (like in a lake).
At least my Johnson engines do. (And Johnson engines are what I'm familiar with, but I believe the concept is the same.)
Don't leave it tilted up like when trailering or it won't drain completely.

Biggest worry I'd have with an outboard, is if there was water in the lower unit which could freeze, but that bridge has already been crossed here..

Running on muffs won't put water in the gearcase unless there is a major seal issue..

Long/short of it is, (unless a seasoned experienced person says otherwise) is I wouldn't worry about running it on muffs now..
I'd probably go ahead and change the lower unit gear oil (if not done when "Winterized"), put the muffs on and run it to check it out for the season.
Just leave it tilted down when done to drain.
With boating season around the corner, I don't think I'd worry about "Winterizing" again..

My newbie $0.02... :)
 

ShoestringMariner

Lieutenant Commander
Joined
Apr 18, 2015
Messages
1,560
And one more thing...
In general, with a new to you engine, it's always a good idea to replace the water pump impeller if you haven't done that already.

I totally agree. For right now I just want to see how it runs. But impeller replacement is due up shortly. The bottom and fluids look brand new. I also wanted it to run a little bit on muffs or at the dock. Then check the oil again so I know whether the lower end needs seals/rebuild also

thanks again for the help
 

jbuote

Lieutenant Junior Grade
Joined
Aug 17, 2016
Messages
1,001
Sounds like a plan! :D
At dock would be better.. Muffs won't tell if prop shaft seals are leaking..
Could pressure test the lower too, but you'd need one of the experienced folks to tell you the max psi it should hold if you don't already know.. .lol
 

ShoestringMariner

Lieutenant Commander
Joined
Apr 18, 2015
Messages
1,560
Sounds like a plan! :D
At dock would be better.. Muffs won't tell if prop shaft seals are leaking..
Could pressure test the lower too, but you'd need one of the experienced folks to tell you the max psi it should hold if you don't already know.. .lol

Make sense about the seals. I did not know I could do a pressure test. I think maybe I should Google some stuff here.
I am going to do a dock test anyway. I need to know if this hull takes on water
 

jbuote

Lieutenant Junior Grade
Joined
Aug 17, 2016
Messages
1,001
Pressure test is pretty simple...
Edit: Drain lower unit oil so it's empty, then do the following...

Use an air pump (like bicycle pump) with a fitting that can screw into your LU drain or fill plug hole. Put plug back in other drain/fill..

Pressurize it to the PSI recommended.. (I want to say 10-12 psi is enough, but please don't take my word on that. Let a pro tell you! lol)
It should hold that psi.. If not, there's a leak.

If you submerge the lower in a bucket of water you can look for air bubbles which would indicate where any leak would be coming from..

That's the basics of it anyway...

Hope; it helps! :D
 
Last edited:

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
If it's a 2 strokes engine and won't be seeing real water any time soon, disconnect engine fuel hose anfter muffs test and run carbs dry till engine drops dead, that way there won't be 2 strokes oil deposits clogging the carbs specially when fuel has evaporated from carbs.

Happy Boating
 
Top