Isuzu 4LE2 RPM

[92U 3406]

Working on a little MMG25 Magnum with a 4LE2 Isuzu (fully mechanical). Engine will not maintain 1800 RPM under load to generate 60Hz. So far fuel supply seems ok, intake is ok. Checked valve lash. #1 exhaust valve was tight so set it at spec. Loaded it up and burnt all the carbon out of the exhaust. If I grab the lever on the side of the governor it easily picks up RPM to spec under 100% load so lack of engine power doesn't seem to be an issue. Right now it drops about 70-75 RPM between zero load and 100% load. None of our other units with this engine drop off RPM like this. Is there an adjustment on the governor to tighten up the speed droop?

Any help would be appreciated

 

[Birken Vogt]

I have been told that a groove can form in the governor somewhere from running at a 1800 RPM for years and years and lead to this symptom. But so far no customer has wanted to pay the cost and fix it.

However, 75 RPM droop is well within what I would consider normal. That is 62.5 Hz no load to 60 Hz loaded, I would expect that from a brand new unit.

If you do dig into it, make note so I can see what is in there better.

 

[92U 3406]

I figured there was something up with the governor. Its got over 10,000 hours on it so its quite possible the governor is worn. I just wanted to make sure there wasn't something simple I was overlooking. I cranked it up to about 1860 RPM no load and at 102% load it sits around 1780. I don't get any more "Gen Under Frequency" shutdowns now with the RPM turned up.

I will get some photos for you if I do end up taking it apart.

 

[tool_king]

I figured there was something up with the governor. Its got over 10,000 hours on it so its quite possible the governor is worn. I just wanted to make sure there wasn't something simple I was overlooking. I cranked it up to about 1860 RPM no load and at 102% load it sits around 1780. I don't get any more "Gen Under Frequency" shutdowns now with the RPM turned up.

I will get some photos for you if I do end up taking it apart.

Sound like your governor might be worn a bit .Did you get it set so you have 60hz electrical output? It is permissible to turn it up a bit to get set right .I had to do it on a few gensets with many hours on them .

 

[DB2]

Not sure if it’s relatable but I had a C240 that would lose power and in the end it turned out the shut off solenoid was improperly adjusted and not allowing full travel to the run position. Burned up a few follicles on that one.

 

[92U 3406]

I haven't had a chance to look at it since I posted. Might get around to it next week unless someone else jumps on it.

 

[Simon C]

I haven't had a chance to look at it since I posted. Might get around to it next week unless someone else jumps on it.

We had some 4LE-2 Isuzu Gen sets with worn governors in Fort McMurray. But 59.8 Frequency is still good at full load. If old fuel I've seen some drop to the point of stalling with less than 100 % load. Can't say I've worked in one of these govenors. Simon

 

[Jay72]

Hello,
Any one know about Isuzu 4LE2 genset speed adjustment.Please share any exprience about it.Genset is almost new only 1000hrs.Want to reduce the Hz from 60 to 50 Hz

 

[Birken Vogt]

Just change the throttle setpoint. Should be a couple screws holding it in place. It is possible the governor parts will not be happy running at 1500 vs 1800. But you will just have to try and see how it works.

 

[Jay72]

Thanks Birken,but its electronic injector and controller

 

[Birken Vogt]

It is going to need a dealer laptop most likely. If they will even do it for you. In case you are not familiar, 60 Hz runs at 1800 RPM and 50 Hz runs at 1500 RPM. The engine was likely built for 1800.