Yanmar 2qm15 transmission parts

[Tmacmi]

The engine of the boat I am considering is whistling (high pitched whine) at a specific rpm going forward.

I haven't spent time diagnosing to see if this happens at the same RPM range in idle or in reverse, so I'm not going to go off the deep end.

It could be a bad belt, tensioner, whatever.

If it is the worst case and its a bad transmission bearing do they make replacement parts and where do I get them?

[Compass790]

Where in the world are you?
I'd check the gearbox oil level for a start. They are pretty tough gearboxes but do need oil obviously. If the oil is dirty or very low I'd be a bit concerned.
You'd have to check the Yanmar agent but you can buy bearings from any bearing supply place for MUCH cheaper than Yanmar agents.
If you are in the USA toad marine is one source for Yanmar parts.
2QM15's are well made engines but quite old now. Good chance it would need a hone , new rings & a valve grind but it depends on hours & how well maintained

[Tmacmi]

Yes, in the US. Michigan specifically. I'll check fluid.

He mentioned that he changed belts. So I'll check that.

Interestingly he also mentioned that he changed to a 3 bladed prop. I have no idea if he crossed checked against transmission gear ratio.

[Island Time O25]

I installed that exact engine (used of course) on a 28 footer replacing Universal 5411. And also changed from 2 to 3 blade. The 2 blade must've been a temp fix as it was not spec'd to 5411, not even close.

Do you know the numbers on the 3 blade?

[Tmacmi]

Don't know the numbers on the propeller. I'll ask. Its possible he doesn't either.

[Compass790]

Originally Posted by Tmacmi

Yes, in the US. Michigan specifically. I'll check fluid.

He mentioned that he changed belts. So I'll check that.

Interestingly he also mentioned that he changed to a 3 bladed prop. I have no idea if he crossed checked against transmission gear ratio.

Well you are definitely in Toad marines dealer area in Michigan as I got some parts for our YSM8 delivered to a friend in Kalamazoo who bought them down to New Zealand for me a few years ago. Or just google Yanmar dealer closest to you.
They can get parts from Japan too, probably come via the master distributor who is located in Georgia I think.

Simple to check if prop is right, assuming boat has clean bottom just see if it reaches max rpm driving forward. Wouldn't sweat it if its 200 rpm under or so.
You can use a long handle screwdriver & press one end against the part of the engine or transmission that you suspect is the problem & the handle to your ear. Watch out for belts etc!
Could be alternator too.
If you've ever seen the movie Das Boot u'll know what I mean.
Good luck with isolating the problem.
Wish we had one of those engines

[Tmacmi]

I'm lucky, I've spent the past dozen years living and loving a 1960 MGA. Full of whines, spits, and hiccups.

I'll wriggle around under there. May well be an older alternator straining under a new belt.

[Compass790]

Oh man if you're experienced on Pommy ( Limey) engines, then Yanmar diagnosis should be a piece of cake!

[Wotname]

All good advice upthread and yes, the bearings will be a common industrial size and should be available at any good bering shop.

However it may be the "new" prop singing. Occasionally they do that - google it, it is a thing.

[charliehows]

erm, ive had one of these gearboxes apart, no nice little bitty synchromesh sleeves and graduated teeth, they are big ugly square tractor gears and if its only whining at one rev range, you are a lucky man. i fixed mine by buying earplugs.

[Wotname]

Originally Posted by charliehows

erm, ive had one of these gearboxes apart, no nice little bitty synchromesh sleeves and graduated teeth, they are big ugly beautiful robust constant mesh square tractor gears and bearings to match and if its only whining at one rev range, you are a lucky man. i fixed mine by buying earplugs.

There, I fixed it for you

[Compass790]

Originally Posted by Wotname

There, I fixed it for you

Sh**T I luv my Anzac buddies ( except where Bledisloe cups are concerned )
but I rebuilt Our YSM8 & still had to reach for the earplug solution
Happy to say it has nuthn to do with the gearbox though, it's just a single diesel racket.
Keep trucking with the 2Qm15 coz it's better than the modern motors IF U WANT TO FIX IT YOUR SELF.
Don't mean to say you don't have to diagnose where the noise is coming from, shud be any eay task for a MG owner.
I had a Triumph 2000 back in the day, it ran different every day!
Can't say it was a bad car but good luck with diagnostics.
It was a ruthless mechanics dream IMO
Hey keep with the 2QM15 idea because it's a good motor, basically it's 2 ysm8's side by side. Depends of course of the one you are buying but the design is sound AFAIK'.
FYI. i have been drinking beer though

[charliehows]

Originally Posted by Wotname

There, I fixed it for you

but I like big ugly stuff... (gotta look in the mirror every now and then)