Yanmar L48 - Running on Slower Speeds

[pdeal]

I have an MEP 531A generator. It's pretty nice in many ways. But, what I don't like about it is that it's about as loud as anything I've ever heard.

I've been wondering if the Yanmar L48 engines can run at speeds that are slower than 3000-3600 rpm. I was thinking like 2k rpm or so.

The Yanmar data sheet I down loaded had a curves down to 1800 rpm or so but I've never seen it done.

It seems like it would be a fun project to try to get one and belt drive a 2500w head with it as a small generator.

[veggie]

I believe the L48 engine is the same as the Chinese L186 air cooled diesel.
(The L186 being a copy)
Even parts are interchangeable.
And yes, they can certainly be run at 1800 rpm.
Would probably last forever at that speed.
The generator I built using the L186 has the engine running at a quieter 2200 rpm.
I think screaming them at 3000 to 3600 is hard on them. But most generators only run during emergencies and only need to last 2000 hrs in their whole life. So 3000 rpm allows for "maximum marketing wattage" 

The problem is that when you slow it down, the close-coupled generator head will no longer be of any use because it needs to spin at 3600 in order to make 60Hz. power.

Good luck.

[pdeal]

I was thinking belt drive.

[Henry W]

pdeal, it's good seeing you on line. The L48 will run fine at lower speeds. The only modification that might need to be done is get some additional shims for the injector pump. If my memory is still good, I believe one 0.10mm shim will retard the timing 1 degree. I'll work on checking it out later today.

I would think 2200 - 2600 is a decent range to try.

Here is a good tip, if you have a tach. Start the engine and go through rpm range from 2200 up to 2600. Whatever rpm the engine runs the smoothest start from there. Most engine's will run smoother at a certain speed. Lots of times a same model of engine will exhibit vibrations at different speeds. This is partly caused by parts stack-up. The less vibration the engine has usually means less stress. If there is no difference then you should be good at any rpm within the range you select.

[keith71]

Don't forget the Yanmar L48ae is a 211cc engine. It puts out a maximum HP of 4.7 at 3600 rpm.  4.2 at 3000
At 3000 continuous rpm it is about 3.8 HP. I am not sure how much it will make at 2200-2400 rpm.

The yanmar LV100ae is the same engine as the 186FA chinese clone. The 186FA is 418cc and makes roughly 10hp at 3600 rpm.
There is also the 186F engine that is more widely available it is 406cc's

You can find the horsepower curves for Yanmar engines online.

[Henry W]

It might make 1500 watts.
I would think 1000 watts continuous.

I'm just guessing. I have not had much time with them.

[playdiesel]

Yes the L48 is the baby sized L series Yanmar and the China clone is the LA170F about 4HP at 3600.
The 186 is the L100 clone which is twice the displacement and HP.
I have a brand new in box electric start L48 Yanmar that is for sale, PM if interested.

[pdeal]

Thank for all the suggestions. As I said in the initial post I have an MEP 531A. It's a keeper. It's over designed as is typical with military stuff. It's pretty capable though. Funny thing about that engine, it's loud and it's more stinky than any diesel I've seen. Generally I like the smell of diesel exhaust but not this one. It had a stupid spark arrester exhaust that pointed to the side and pretty much guaranteed that if you start the generator you'd smell diesel smoke afterwards. I took this off and put an elbow pointed up that made sort of a vertical stack. This is better.

Anyway, just thinking at this stage. I was looking more at the specs last night and the L70 and L100 do get pretty heavy. My interest here with this post is for a small and quiet as possible diesel generator for tossing in the back of the truck. Part of what motivated this is that I was working on my deer stand a few weeks ago. As I headed out there I plugged my Makita battery charger into a 400w inverter and it didn't have the umpf to do the job.