F25 Bogged down and somewhat siezed up on the water.

[wikdslo]

Hey all.

I'm new to the boat repair world. I've been doing the car world for over 20. I've owned this motor for 4 years now and it's been rock solid.

It's an F25, 25 hp Yamaha outboard. 4 stroke.
Oil was fresh last year and it only ran a couple of times. Checked it this year and it looked brand new and was on the mid mark of the dipstick so I left it alone.
At the end of every season, I always run the boat out of water with a water feed to warm it up, then drain the lower unit gear out and replace it with fresh to start the season.

I took the kiddo out on the water yesterday morning, ran smooth as could be. We were going along and all of a sudden the motor bogged down a bit.
I backed off the throttle, and tried giving it a bit again but it bogged out some more.

I backed right off the throttle thinking maybe there was gas feed problem, but it was clearly something else. I saw some steam/smoke coming off the motor so I cut off the ignition.

Upon some inspection on the water, the tunnel (lack of a better word) that is the lower unit was piping hot and I think the smoke was just steam/grease/dirt burning up.

I didn't do anything else with the motor. Rowed that puppy back to shore and put it on the trailer. When I got a chance to look it over, there is what looks like gear oil coming out of the water intake vents on the lower unit.

Prop spins freely, and the motor fires right up no issues.

I didn't do anything else with it. The row took me over an hour and I was pretty pooched.

Looking for advice on where to start and what might need repair here.

I suspect that maybe the water pickup had failed and the lower unit wasn't getting cooled? Maybe that cooked a seal and now the lower unit gear oil is leaking from there.

Thanks for the help people. Much appreciate any advice I can get.

 

[racerone]

Drained the gear oil.------I picked up a 2010 model F25 last fall.-----Gears crunched.----These gears / lower units are not robust in my opinion.

 

[wikdslo]

Drained the gear oil.------I picked up a 2010 model F25 last fall.-----Gears crunched.----These gears / lower units are not robust in my opinion.

Care to elaborate a bit on that?

Do you mean that my gear oil got compromised and that's what caused my issues?

When I pulled it out of the water there was clearly still gear oil leaking out of it after over an hour of paddling through the water.

 

[racerone]

Up to you to check if gears / gearcase is in good condition.----I can not see or touch your motor.----Perhaps a plastic bag wrapped around the unit and cut off water supply.----Do you put a new impeller in every 5 years ?-----Time for you to drop the lower unit to inspect gears / water pump / metal bits in the oil.

 

[wikdslo]

Up to you to check if gears / gearcase is in good condition.----I can not see or touch your motor.----Perhaps a plastic bag wrapped around the unit and cut off water supply.----Do you put a new impeller in every 5 years ?-----Time for you to drop the lower unit to inspect gears / water pump / metal bits in the oil.

I have not done anything to this unit other than doing the regular oil changes as necessary and the gear oil every year, along with fogging the motor at the end of the season.

Boat has only sees about 5 - 10 hours of use per season, but I'm not too familiar with boats.

Looked over the impeller replacement a bit. Seems like it's a routine maintenance job that I didn't do!

So at this point, I'll drop it down and inspect everything. But any advice of what I'm looking for specifically with the gears. Are we talking signs of heat discoloration?

As for the water pump, I'm going to operate somewhat under the presumption that it was a failure point somehow and this thing overheated. That being said, would that only affect the lower unit or the motor as well?

And what would cause the gear oil to end up in the water intake area? Is that a seal related to water pump kit or something separate?

Thanks again. Much appreciate the info.

 

[racerone]

??----The lower unit is submerged in water.----Therefor it not likely to overheat !!----Likely overheated the powerhead.----Now on 4 strokes the oil is a heat sink.----Hopefully you dodged a bullet / expensive repairs.----Check the gear oil for metal bits.

 

[wikdslo]

??----The lower unit is submerged in water.----Therefor it not likely to overheat !!----Likely overheated the powerhead.----Now on 4 strokes the oil is a heat sink.----Hopefully you dodged a bullet / expensive repairs.----Check the gear oil for metal bits.

Gotcha. Will do.

So this was the area that was hot to the touch. I made the general assumption that everything above it would also be rather hot and did not do any detective work on that one

Is there a seal that has let go allowing the gear oil to go into the water pickup? Or would that be one of the parts included in the water pump kit that would otherwise be getting replaced when I do that job?

Thanks again for the help.

 

[wikdslo]

Got word back from the repair shop today.

They said the impeller had torn itself to bits and the casing had melted.

They replaced all of that, did new spark plugs and cleaned the carb. They tested the motor for compression and compression was good.

They found a slight water leak from the head gasket, but told me to run it until it dies but don't bother fixing it.

They said they suspect the head has severe warpage from overheating which is what's caused the water leak, but they aren't sure. When I asked about have the head milled to flat and do a new headgasket, they said there is almost no tolerance on the motors so that wasn't an option.

I'm hoping someone here might be able to chime in a bit and offer up some info on the situation.

Is it not possible to have the head decked and do a new head gasket?

Is there any long term issue from running it the way it is?

They told me because it's an older carbed version of the motor and the new ones are fuel injected the costs would be too high and wouldn't make it worth it.

Thanks all.

 

[racerone]

Was the motor ever started with no cooling water to the impeller?-----I agree----These fancy 4 strokes are fast becoming a " throw away item "----Labor repair costs here can not compete with factory labor and robot manufacturing.----Think about it.----If you machine the head flat, then how do you keep the camshaft bearings " inline " on these !

 

[wikdslo]

Was the motor ever started with no cooling water to the impeller?-----I agree----These fancy 4 strokes are fast becoming a " throw away item "----Labor repair costs here can not compete with factory labor and robot manufacturing.----Think about it.----If you machine the head flat, then how do you keep the camshaft bearings " inline " on these !

The boat was only ever started in the water. Last year to winterize I used a hose with the little clamps to run it and winterize it.

This happened the first time I took it out this year, and I didn't think to look if there was water coming out when I first started driving it, but either way, on route the impeller failed and I had this issue.

Just trying to find out if rebuilding the motor is a viable option or not?

 

[racerone]

Change oil in the power head.-----Start the motor up and see how it runs.

 

[wikdslo]

Change oil in the power head.-----Start the motor up and see how it runs.

The shop did that all. They said it runs fine. But it's leaking a drop out of the headgasket.
As mentioned, when I asked them about me just pulling the head and milling it at a machine shop and installing a new headgasket to fix it, they said it can't really be done due to a lack of tolerance on these motors.

Just wondering if that's the case and if there is another method I can repair this thing with, or, as long as the compression is fine and it's runnign fine, do I just run it as is and not worry about that leak?

Thanks again

 

[wikdslo]

An update on this.

The shop didn't do the most thorough job in the world.
They said they checked compression, but they did not.

I took it out on the water and ran it. it ran great and smooth for about 15 minutes then it started to lose power. Didn't like to idle either.

I got back in and found the oil full of water.

I've since torn off the head, found that the left bank of bolts was sitting at a mild level of hand tight if even. The right bank was on super tight as one would expect for head bolts.

I think it's safe to say that the headgasket was no longer doing it's job.

The head looks fine, no cracks. Going to get a straight edge to test it and see if and how much it's warped. But I'm inclined to attempt to machine a bit off and put on a new headgasket and go for it.

Is there any spec on how much can be machined? Is it an interference issue or is it because of the lack of a tensioner on the timing belt.

That belt was on there super tight, that I can't see how taking off a bit from the head would cause any issues for it down the road.

Thanks

 

[flattop1]

Jmho.
A piece of glass and some 400 grit wet and dry . Reassemble . New gaskets . Torque everything .
Otherwise the consensus that it's
Time for a different one is pretty correct.