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Outboard motor guys
jimdeere
Member, Moderator Posts: 26,158 ******
My friend just bought a boat with a 25 hp Mercury outboard. He was able to try it on the river before he bought it. He said it died on the way back to the landing but he went ahead and bought it beit was a good deal.
Sitting at his house, he says it will start but die and there's not much water coming out of the weep hole. He thinks it's the water pump.
Neither of us knows anything about outboards but he got on YouTube and wants me to help him replace the pump.
Questions:
Do outboards have a safety that shuts them down if there's no water flow?
How big a job is it to change out?
Are there any things we can check before tearing into it?
Comments
Easy to do. Go on you tube. Get short video on changing water pump. It takes about 20 minutes and needs done every three years to avoid over heating. Also, check the pee hole to make sure there is no mud Dauber nest in it, they love to plug that hole! Make sure you get the vanes in the proper form on the new pump, put grease in the hole where the impeller goes so it has lube on first start. NEVER EVER START AN OUTBOARD WITH OUT WATER!! Use an adapter or garbage can filled with water to make sure the pump is not ran dry.
I seal the pee hole with a light dab of grease to keep the daubers out. It works great and blows right out when the engine is started.
Sounds more like a fuel issue to me. Check the fuel filter.
Have him pull the little plastic piece that the motor 'pees' out of and make sure it's clear. Re-install it and see if there's good flow. Most newer engines will warn you and then shut down in an overheat situation but not necessarily a low water flow situation. Changing out the impeller is pretty easy IF that's the problem.
Is he running the motor in a tub of water so that the impeller is actually drawing in and circulating the water or does he have it hooked up with rabbit ears and a hose?
Hose.
Highly unlikely that a 25hp would have such a safety. What year model is it? Fuel injected 4 stroke? Carbed 2 stroke?
If fuel injected, the fuel pump may be bad. Dad's Yamaha had a fuel pump go out with less than 1 hour in the brand new motor! Would not crank at all however.
If carbed, then carb needs cleaning. This is what it sounds like with no other info.
Bad water pump will just make the motor run hot and melt/destroy the motor.
Water pump is easy to change, recommend getting an OEM one! BUT that is not the main issue here. Water will not come out of the motor will not stay running more than 1 or 2 seconds(has to have time to prime)
COULD be as simple as a hole in the fuel line from the tank!
Oh yea, forgot to mention, make sure the vent is open on the gas tank. Don't ask me why I know this, now.🤗
Find a garbage can or something to dip the engine into and run it that way. That'll show you right quick if your impeller is operating. When it's hooked to a hose the water pressure from the hose will cause some flow out of the pee hole.
Like Bpost just mentioned, make sure the gas tank vent's open. That could definitely cause the symptoms you're describing.
If a carb engine could be: 1. Electrical - coil or condeser or spark plug. 2. Fuel jets or float. 3. A bad impeller will only make the engine overheat. Steam comes out of the discharge. I don't know if a overheated enginw will shut down. They will run hot if they get a little water. Good luck.
It could be operator error.
And fiery auto crashes
Some will die in hot pursuit
While sifting through my ashes
Some will fall in love with life
And drink it from a fountain
That is pouring like an avalanche
Coming down the mountain
It very well could be.
If you run it in a tub, don't put it in gear! The prop will wash the water out of the tub. Pull the prop if he wants to test run it in gear. "Don't ask me why I know this, now."
I would bet on a dirty carb, probably from sitting. If he can get it to run, I would:
Do check that stream, though. If the motor is running hard, then water shouldn’t be just trickling out; should be a strong stream.
I would start with the fuel line, and primer bulb. You should definitely replace the impeller.
Before leaving the boat ramp boat dock area
Get two big paddles and always go up stream and keep the wind in your face. (go up wind)
Paddling downstream and with the wind at your back is a big help.
Do not ever get downstream with a paddle.
How do I know this sort of stuff.
I once owned a old Champion outboard motor. It would always start and run good around the boat ramp area or if in site of the boat ramp. Get downstream and or out of site of the launch ramp and it would not start. I loaned the motor to a guy and told him such. He said he did not believe me until now.
I keep a 3 ft piece of string trimmer string in my boat for those occasions when I get into a shallow/muddy area, run it up the "pee" hole a couple of times. Has always worked for me (for mud). Even plugged, the motor should still run (until it burns up of course).
Probably a fuel issue as mentioned , more than likely the carb needs a good cleaning .
Do you know this because someone you know did this?
And fiery auto crashes
Some will die in hot pursuit
While sifting through my ashes
Some will fall in love with life
And drink it from a fountain
That is pouring like an avalanche
Coming down the mountain
He said not to ask.
😄
You'd probably get the same answer from @bpost
Updates?
You need a bigger tub! I left the prop on my DF140 and kicked it into forward and reverse in about a 200 gallon stock tank. I think it would make one hell of a margarita mixer!