Yamaha 250’s Outboards

[W&KO]

Anybody happen to be running Yamaha 250 outboard motors??

I’m now responsible for 6 of them….have a question or two…

[p38arover]

Motorbikes or outboards?

[W&KO]

Motorbikes or outboards?

My bad, i thought posting in the boats and fishing section would have been clear….

Yamaha 250 Outboard motors…

Cheers

Edit, I cannot change the title [emoji20]

[trout1105]

When I was up in King Ash Bay by far most the professional crabbers were running big Yamaha engines on their boats and despite the constant abuse they kept on running perfectly.
Great outboards, Just keep up the servicing of them and they will give many years of reliable service[thumbsupbig]

Thank the Gods that Landrover don't make outboards[bigwhistle]

[BradC]

Edit, I cannot change the title [emoji20]

I can.

[Saitch]

I know several blokes with larger Yammie outboards and in general, they seem a very good motor.

Another thing to look at is that the likes of Grady White use them and 'If they're good enough for GW then they're probably pretty good!'....................business deals aside.[smilebigeye]


P.S. I do remember that there were supposed to be a couple of issues with the earlier 350 hp, one being flywheel problems, but I would think/hope that these have been sorted by the manufacturer.

[scarry]

I had one for years,as Trout said,keep the servicing up and it will look after you.

Never had any issues at all with it,but it’s been gone quite a few years now.

[NavyDiver]

Mines 1/2 that size and about 10 years old now. Runs like new still happily. I did have a minor water blockage needing the water pump impeller blade replace. It was not that hard to get the boot off to fix it.

[trout1105]

Mines 1/2 that size and about 10 years old now. Runs like new still happily. I did have a minor water blockage needing the water pump impeller blade replace. It was not that hard to get the boot off to fix it.

I usually replace the water pump impeller on an annual basis regardless of size/brand of outboard, Not that expensive and not that difficult to do either [thumbsupbig]

[W&KO]

Our six 250’s, even the brand new 2 that have 23hrs on them, well 23hrs last week when I did the initial 20hr service all make oil………a lot off oil.

Google seems to indicate it is a bit of a problem.

I don’t know the full background of the 250’s we are are running but Yamaha have instructed us to run the hotter.

OEM thermostat is 52 degrees, we now run 60 degree thermostats as directed by Yamaha. I just replaced the thermostats in the brand new engines. I was gobsmacked how much oil they had made.

The older engines that have been running the 60 degree thermostats for years make significantly less oil.

I know, I know, while we calm it making oil the correct name is probably oil dilution??

The 150’s and 100’s we have don’t have the same issue.

[Barraman]

I’m running a Yammie 250 Vmax SHO.

What does “making oil” mean? Whatever, I don’t think my motor is doing it. Coming up to 300 hrs and never missed a beat!

[W&KO]

I’m running a Yammie 250 Vmax SHO.

What does “making oil” mean? Whatever, I don’t think my motor is doing it. Coming up to 300 hrs and never missed a beat!

The oil level increases between services.

It’s apparently more common where there is an issues with the octane in the fuel…..

The V8’s are having more issues than us with V6’s as they cannot get 98 at all, I believe the V8’s require 98. One company runs quad V8’s on their boats and have all sorts of troubles due to quality of fuel.

We service @ 100hr, we add new oil to about 3/4 between the low and high mark, the the time 100hrs comes around we are well above the high mark sometimes as much as 1/2 the distance between low and night marks.

We run the engines with a slightly higher thermostat which seems to reduce the oil make.

One theory is every time the fuel is transferred you loose octane.

I’ve suggest adding an octane booster but haven’t received much excitement apart from it would be difficult to manage.

We have have 8 V6’s Seven 250’s and One 150, all make oil to some extent.

[Barraman]

Mine doesn’t do that!

[roverrescue]

Hey mate

Essentially some of the big block yammies are good at leaking fuel down past the rings. Yam says it is their super hardened piston bores - I reckon it is just a company like Toyota that is very happy to live on reputation!

Anyways / the solution (even as per yam) is make sure you are propped right to the top of the rev range. Ie light load you should be hitting limiter - normal loads you have to hit 6000rpm.
So get your engine height right
Then the prop right
Then run them like **** at WOT for a few hours minimum. This will / should seat the rings and bores.
And then every time they are used make sure you hit WOT even for only
A few minutes


It is the only way


Oh obviously during the bedding in phase regular oil changes to ensure minimal dilation.

Those new engines at 23hrs need it most but the technique also works on engines with more hours

What boat is it
What numbers are you getting at the moment

RPM / speed at WOT

[W&KO]

Hey mate

Essentially some of the big block yammies are good at leaking fuel down past the rings. Yam says it is their super hardened piston bores - I reckon it is just a company like Toyota that is very happy to live on reputation!

Anyways / the solution (even as per yam) is make sure you are propped right to the top of the rev range. Ie light load you should be hitting limiter - normal loads you have to hit 6000rpm.
So get your engine height right
Then the prop right
Then run them like **** at WOT for a few hours minimum. This will / should seat the rings and bores.
And then every time they are used make sure you hit WOT even for only
A few minutes


It is the only way


Oh obviously during the bedding in phase regular oil changes to ensure minimal dilation.

Those new engines at 23hrs need it most but the technique also works on engines with more hours

What boat is it
What numbers are you getting at the moment

RPM / speed at WOT

All engines were run in as per Yamaha instructions

I’m not in the boats to see how they operate, I just service/fix em but rarely drive em.

We also prop our for more low down grunt and sacrifice top end.

The skippers are instructed to cruise at 30knots for the bulk of the tour if the tides/current allows, keep in mind we are operating in the 2nd biggest tides in the world. Largish boat with 12 punter on boat.

The other day I went on a 2hr tour to listen to an engine that’s making an unusual noise.

On the home run, spring tide, skip was at 24knots @ 4300 rpm, my the time we turned into the bay we we on 32knots at 3700 rpm, give you an idea on the current we were pushing into.

On one off out tours the skippers have the engines at WOT plenty, and that just to get them moving……with the engines in neutral we we floating at 8knots, this can be as high at 14knots.

[roverrescue]

Yup
Maybe the owner needs to call a certified yam tech
Yamaha have on many occasions detailed what I wrote as the solution to fuel leak down

Irrespective of run in

The problem is ring sealing
The solution is engine load / heat whatever

Unless your engines are turning 6000rpm at WOT
A/ you are killing them slowly
B/ they will make oil forever

“Propping for low down grunt” is a bit bush mechaniccy but essentially propping them with a lower pitch prop so they reach the limiter easily is actually what you want….

If you wanna fix the problem

Irrespective of currents
They need to be pinging the limiter with no PAX and hitting 6000RPM with a normal fuel and PAX load

Run them however you want for efficiency

But the “test” is as above






Just the way it is mate

[roverrescue]

Am I guessing you’re company is running to the horizontal falls?

Crazy country there for sure!!!

The other day I ran over to Horn Island
About 35nm
Weather was average on way over into the current used about 50L at 25kn

Coming home weather was atrocious 25-30kn solid greenies everywhere - was still able to make 20kn headway with the current - ended up using about 30L

Amazing what a few less rpm and 4kn of current makes to efficiency….

S

[roverrescue]

Cure for insomnia
Google

site: thehulltruthYamaha making oil


I gave up after counting 39 distinct threads on it

Very very very common

S

[W&KO]

What boat is it

All three big boats make oil to some extent

I’ve been chasing a noise that’s developed in one engine on our ASIS 9.5 amphibious……

Just swapped gearboxes across the two donks…Port to starboard and starboard onto Port.

The noise followed the Port gearbox………..at least we know it not an engine issue. Given the Port is a left spin box it has a few more turning bits inside. Maybe this is still an original box and has 1800hrs on it as most of our boxes get crunched and need rebuilds or replaced.

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