06 2 st Yamaha 70hp loud ticking/clicking noise

[mitch_wahoo]

Hey guys and girls,

I've just brought a seconhand hydrofield with twin 70hp yamaha's on it. The motors only have 150hrs on them. Went fishing today and both motors ran fine until we got back in the harbour and noticed one of the motors has a loud ticking noise coming fron around the flywheel area. No alarms went off on the gauges.

Seems to be running fine apart from the noise. starts fine idles fine and revs fine. Its no different if its in neautral or in gear. Noise is still present. Got home and took the cowling off and started motor and definately coming from around flywheel somewhere.

Took the flywheel off and there was nothing stuck under there or no loose bits.

Has anyone else had a similar problem? Any help is much appriciated.

Thanks, Mitch

[cormorant]

I'll go for a cupie doll

Depends what sort of click noise

Spark plug lead breakdown and a arc to block? Stuff a rag up the exhaust ( for the neighbours) and start with cowl off and see if you see a spark arc.

If they are injected - injector?

2 strokes - a reed?

Starter not disengaging properly
loose magnet in flywheel.
Butterlfly loose on air inlet

I'm not going to suggest the other ones as they get progressively more expensive , gudgeon , piston slap bearings. Pretty unlikely

Grab a stethascope with a metal needle end on it and you will narrow it down quickly. Stick the needle tip right through a old ear plug defender so you can't touch the tip on the block and deafen yourself.
If not when running pull plugs and see if the noise exists on the starter motor / pull start

Hope it is something dumb , simple and cheap

[mitch_wahoo]

Thanks forr the info comorant.

I dont think it could be spark plug breakdown as it seems to run fine. The engine is a 2 stroke. i dont know much about reeds and how to ckeck them. Have had the flywheel off and nothing was loose under there.

Starter is disengaging fine. Butterfly could be loose as i didnt check that.

Im hoping that is not one of the bad problem you have suggested.

I contacted the guy i brough it off and he said the same thing happened when the motor was still under warranty and it was the stator.

Im goin to get a yamaha mechanic to look at it this week i think.

[Spaniard_King]

Top piston big end bearing. I hope it isnt as it wont be cheap. If it is get the crank repaired dont let them talk you into a new one.

[mitch_wahoo]

Spaniard_king I hope it isn't the big end bearing. I'd be shattered if it was. Is there any way to check to see if it is?

Surely it couldn't be anything that serious. The engines only have 150hrs on them.

[Owen]

I know you think it's coming from the top end but don't rule out a gearbox that's lunching itself
Been on two different boats where that kind of noise started and both were gearboxes that had copped a smack months before
Worth checking before you strip the motor




Cheers
Owen

Sent from my iPhone using Tapatalk

[oldie]

My father has a 70Hpo Yamaha and although its older really does sound like what happened to his motor, and my brother was still using it and running fine, i went out and heard it and said that does not sound right it sounded like slapping or knocking, they ended up taking it in and needed rebuild, scored cylinder i think, or issues with the piston. This was a very noticeable sound!

[mitch_wahoo]

It's not really a slapping or nocking noise. Just a ticking or clicking noise like something it touching on the flywheel.

[mitch_wahoo]

Well the yamaha mechanic looked at it yesterday arvo. Not good :( Something has in the crank has let go. He thinks a bearing.

The piston or bore isnt scored at all but there is 3 tiny dints in the top of the piston where a peice a metal has been in there and gone strait back out the exhaust.

The mechanic has taken the motor and is goin to strip it down and see exactly what has failed.

He said its strange that it happened as the motors are like brand new and it could have been caused by something like a dodgy bearing from the factory yamaha brought them off.

Just unlucky i guess...

[Crocodile]

Hello mitch_wahoo,
$$$$$$$
B.O.A.T. Bring Out Another Thousand.
Sorry to hear the news.
Please keep us informed as I have a 60 and am very curious.

[mitch_wahoo]

Got some good news back today.

The mechanic pulled the motor down. Theres a ring that holds the crankcase together wich has a locating pin. The pin came loose and went throught the engine and strait out the exhaust without damaging anything :)

The ticking noise was the ring spinnig. He said he has never seen this happen in the 10+ years he has been working on yamahas.

The best bit is it's only gonna cost me around $600. He also said the engines are like brand new inside wich is a plus.

On the downside... i wont be able to use the boat for abother week and a half

[OPTI]

let me guess ,no parts in australia???

[mitch_wahoo]

No theres parts in aus. I live in yeppoon and the cranks gotta be sent away to have a new ring pressed onto it.