Hi. New here. I have a 2001 hitachi ex35u mini excavator with a Isuzu 3LD1. I’m doing a small restoration on the excavator and have the engine out to paint it. I noticed the crank pulley can be spun independently from the crank. There is resistance but it is not “loose” and doesn’t wobble. Also the battery light has been on since I’ve owned it the last year but never any charging problems. Is this pulley not supposed to be able to spin independently? Could it be the pulley slipping causing the alternator to not spin fast enough to keep the light off. This pulley also spins the belt that spins the fan and this engine has never come close to overheating at all. Thanks for any help.
Yes to all of the above. You need a new one, or send it off to a harmonic balancer rebuilder if you can't find a new one. There's rubber between the two pieces to absorb some vibration from the crank and keep it from cracking. If that rubber wears out and loses it's grip, you need to replace it. If it's not rubber between them, then it could be some viscous fluid that I've never seen, and I could be all wrong, but I doubt it.
Thanks for the help. There is rubber between the pulley and balancer. I’ve never seen one slip but also be such a tight fit. Made me wonder if it was maybe supposed to be like that.
Just watched this the other day. Looks like the same engine. skip to 19:30.
a lot of three cylinder engines don't have a harmonic balancer, I guess they let them shake? A six cylinder engine is inherently very well balanced, that makes a three cylinder have about the worst balance, unless you compare to two and one cylinder engines. Hard life for a harmonic balancer on a high speed unballanced engine.
Phil314, excellent find. My hitachi 35 is the same exact machine as Jessie’s Deere 35 in every way, except mine has a cab. What’s hilarious is I watch Jessie and Andrew ALL the time. I’ve even started this video but never finished it and had I then I would’ve seen this. I got a quote for $140 to have mine rebuilt with a lifetime transferable warranty. I think I’ll go that route.
Running at 1800 RPM, some of the 3 cylinder engines are the shakingest engines you ever seen. Try to take a picture of the serial number while running, all that comes out is a blur. Eyes can follow it but camera can't. The 3L are probably the least shaky, the worst is the Yanmar 3TN? shakes like a paint mixer. Also known as Isuzu 3C? Good engine overall though.
So I was gunna go with rebuilding my harmonic balancer, $140 for the rebuild,$15 to ship there, and another $15 to ship back would’ve totaled $170 and we weren’t sure where the timing mark was supposed to be on the slipped pulley. The local Deere shop said $200 for a brand new one and I wouldn’t need to worry about positioning the timing mark. Just went with a brand new one and had them send me a front main seal while I was at it. Then said well since the motor is out I’ll the a rear main too. It wasn’t leaking oil but with 4500 hours who knows how long they had left and I’ll be dipped if I put that motor back in and it started to leak from either. Balancer wasn’t even tapered so it came off almost by hand. When the balancer was off I looked in at the crankshaft and saw a dimple on the front crankshaft gear that was located 90* counterclockwise to the shafts key. I placed a bet that that was where the pulley mark was probably positioned too. And what do ya know that when I got the new balancer the pulleys timing Mark was 90* counterclockwise to the key haha