yanmar 6LP-DTE 250hp?

Badlatitude

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I remember the STE or STP or something like that being real bad. Anyone have any opinion on the Yanmar 6LP-DTE engines 250hp?
 

Eslang

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I remember the STE or STP or something like that being real bad. Anyone have any opinion on the Yanmar 6LP-DTE engines 250hp?
Awesome motor
Toyota base engine
Marinized by Yanmar
No issues with the 250/260 motor
Some of the early 315s had valve breaking problems
Timing belt motor. Have to change timing belt before it breaks or risk internal engine damage as it is an interference engine.
Engine runs like a swiss watch. Very smooth, very quiet, very fuel efficient
 

Nighthawk

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There was no real bad 6LP engine but I think what you are referencing is the two Service Bulletins issued for the 300 and 315 HP 6LP engines around the 2000-2001 time frame that eventually became a class action suit. Yanmar tried to tighten up valve seal blow by when cold and changed the guides. At high EGTs, mostly in fast planing hulls where boats were not propped to reach 4000 rpms an exhaust valve could hang up in the guide and take out a cylinder. When I bought my boat I made it a condition of sale that Yanmar accomplished both Service bulletins (new seals, new exhaust valves). They did that and 1200 hours later the engines are still flawless.

The DTE has some subtle differences between the STE model one of which is the useof shims to establish correct valve lash instead of adjustable screw and locking nut found on the STE engines. Both require timing belts at 1200 hours and that would be something I wouldn't ignore as these are contact engines. At the 250/260 hp variants they are outstanding engines.
 

captainlarry84

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I also agree a great power planet & yes the timing belt is a must & 1200 hours. The 315 is zero tolerance on valve contact. I am not sure on the 260. But either way if the belt goes you are dead in the water. Both motors are rated @ 38000 RPMs WOT and continuous @ 3600 RPMs. The 260 HP had a much different head then the 315 which is where most of the power increase came from. The 315 sports 4 valves per cylinder whiloe the 260 has two per cylinder. I know the 315 HP has shimmed valves, however I am not sure about the 260 HP model.
 

Crazy Ivan

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Bump, anyone have opinions on the 315 hp ones?

I have a 260 HP 6LPA in my boat but I have worked on dozens of 315 HP's. Never seen any problems with them. They must turn 4000 RPM wide open, this is crucial.
 

restless

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Bump, anyone have opinions on the 315 hp ones?

I like the one I have. It only has 1000 hours but so far so good. I'm not crazy about having to change the timing belt at 1,200 hrs but we'll see how that goes. It starts instantly , even in winter. Runs very smooth. Pretty damn economical.
 

mudhake

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I have installed 35 of the 315hp yanmars and propped them correctly to turn 3900-4000 rpm and no one has had a major problem as far as I know . Some of the six passenger boats have 6 to 7000 hrs on them and are still going strong. These guys have maintained them to a tee and it has payed off.
 

mudhake

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I know a guy that worked for mack boringfor years that knows these engines inside and out that is out on his own. If you need help with a yanmar let me know and I will hook you up with him.
 

8675309

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I had one in my Albin and the 315 was one great engine, fast quiet and great fuel burn. Nice engine if you take care of them.
 

davidgmcmahon

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Hello ,
I am looking for a mechanic to work on my 6 lp motors in Barrington RI ? I would like the valves adjusted . Do you have a suggestion ?
Thank you ,
Dave
 

32Foolim

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I realize this is an older thread, but i am currently looking into a set of 6LP's @ 260hp with 1700 hrs on them. Could I replace the timing belt with a chain type settup? this is toyota block from what ive read. if possible how would this affect the motor?
 

Nighthawk

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I just did belts on mine. One of the easiest timing belts to replace on any engine I have ever worked on. First one took 45 minutes, second one literally 20.....you don't have to by the Yanmar $80 belt, Gates and others all make the same belt for about $25.

Unless you have zero space in front of your engine don't be afraid of this job, it's quite simple.
 
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