Yanmar 6LY2-STE 440HP Opinions

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Battledeck

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Hi Crew.
I am a new forum user from Australia.
I am considering importing a boat from the US and has Twin Yanmar 6LY2-STA 440 Hp motors with 600 hours.
I would like any opinions on the motors, things I should look out for and any rebuild problems that might exist when that time comes.
Thanks Stephen
 
Last edited:
Steve,

Is there any chance you can sea trial before completing purchase.

6LYA2 is a good motor, however it has been coming in for stick in US boating press of late, for example relations between Hinkley and Yanmar distributor are at a real low ebb.

Going back to basics, some US builders prop engines 'on the edge'. The is a real high performance motor and MUST be propped with care, WOT is 3,300 rpm and engine MUST reach at least 3,360 clean with half full tanks. Now here is the rub, Yanmar tachs always seem to be around 200 rpm optimistic which is where trouble starts.

Golden rule is to always strobe the tachs and get them as accurate as you can. Too many boats are out there with optimistic tachs. Many of the prop shops in the US do not always have calibrated brains, cos the motor says it is 440 they dig no deeper, do not even realise that motor is nowhere near 440 due to cool test fuel density and the Hp is quoted in Metric horsepower (CV) not real horsepower. Net result is overpropped boats.

If motor can reach a genuine 3,360 at WOT you will have no worries at all. If motor has been run for 900 hours overloaded it will have no future. Usual failure mode is caused by high EGT weakening valves at friction weld, head pops off valve and it is tears before bed time.

Very robust motor, however 106 mm bore LY's are NOT repairable, if bome becomes damaged block is scrap.

If engine reaches calibrated 3,300 rpm on trials life is a and will continue to be good.
 
A mate of mine had one in an offshore 2000, went really good, only had one problem with it, the crankcase breather feeds back into the air intake it had been breathing it's own ****, and consequently bunged up the intercooler, causing a lack of power and loads of black smoke, and restricting the revs to 1600. I must add however that the engine had never been serviced prior to him aquiring the boat, and following the clean out and service never gave any problems.
 
Some Great advice there .
Much appreciated. Sea trial will not be a problem so I will be sure to have those things checked when surveyed.
Thanks Stephen
 
Just one other wrinkle, when you do an oil change, have plenty of wipes handy, those overhead filters are a nightmare. You'll see what I mean when you get under the bonnet.
 
Battledeck said:
Hi Crew.
I am a new forum user from Australia.
I am considering importing a boat from the US and has Twin Yanmar 6LY2-STA 440 Hp motors with 600 hours.
I would like any opinions on the motors, things I should look out for and any rebuild problems that might exist when that time comes.
Thanks Stephen
Click to expand...

G'day Stephen and welcome...

Am I allowed to ask what these engines are powering?

Good luck with the deal.
 
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