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!
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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.Quote:
Originally Posted by Barraman
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.
Mine doesn’t do that!
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 instructionsQuote:
Originally Posted by roverrescue
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.
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
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
Cure for insomnia
site: thehulltruthYamaha making oil
I gave up after counting 39 distinct threads on it
Very very very common
S
All three big boats make oil to some extentQuote:
Originally Posted by roverrescue
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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