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Old 02-09-2017, 12:24 PM   #4 (permalink)
Stubby79
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Quote:
Originally Posted by oil pan 4 View Post
The muffler is big, made of thin metal and not well attached.
I also tried to power my 2.5hp air compressor that runs close to 5hp at shutoff with this generator and it couldn't get the compressor going up to speed.
It just couldn't handle the start up surge.
Engine slow down? If it was maintaining speed, then the weak link isn't the engine.

Hold on a sec...7kw? That's presumably surge rating. For a second or two while something is starting up.

That motor is rated at 8hp gross...which are about 15% overrated...so now it's 6.8hp. You're trying to get 5hp out of it. Is that measured at the plug? I'll assume so. So, if your engine is putting out what it's supposed to, then you need your generator head to be at least 73.5% efficient. I think that's a bit on the high side (though maybe at peak they're noticeably more efficient).

Anyway, I think your machine is grossly overrated. And that you won't be able to get that much juice out of it. The generator heads I see online recommend ~13hp for that kind of power. That's not a small difference that you might be able to squeeze out of it with a tuned exhaust.

If you don't need as much airflow as it puts out, you could consider changing the pulley size so that the motor isn't loaded nearly so much. Assuming it's belt driven.

Last edited by Stubby79; 02-09-2017 at 12:45 PM..
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