Crankshaft pulley

[richfirefighter]

Hello, I am in San Carlos Mexico and had a pulley break because my alternator seized up! I have been trying to get the pulley/harmonic balancer off and had no luck! Is there a way to do this? I have the boat with a mechanic shop now and he wants to lift the motor up to get to the bolt going thru pulley and to also have room to put his pulley extractor on once the bolt is removed?? I am very nervous about having this done bye a mechanic I am not familiar with? Any help would be much appreciated! My number is 309 840-5314 ...thank you very much ! Rich

 

[knotflying]

You don't mention which motor you have. That may be some help in order to provide advice.

 

[doke01]

If you have a Yanmar 125HP like I do and an earlier R-25, mine is 2007, I can perhaps provide some guidance. I had a leaky front camshaft oil seal. I needed to pull off the pulley/harmonic balancer to fix it. The only way that I could do this without lifting the motor was to cut out part of the floor around the front of the step going into the boat. There is a photo of how this came out in my album (2016 photos). However, if you are unable to do that you will need to lift the motor to get enough access (this was my plan B). It was really difficult to pull the pulley and I broke two pullers before I found one that was strong enough to do the job. It took a lot of time and effort and if you are not comfortable around engines, I don't recommend you do it yourself.

It sounds like the mechanic is telling you the right thing, assuming the pulley is actually broken (not sure what you mean by broken, is it just spinning? If so there is a key in a keyway in the shaft that may have broken, where you would need to remove the pulley to replace it). There really isn't enough room to do the work if you can't remove part of the floor to get more access, so what you are being told would be correct regarding lifting the motor.

 

[richfirefighter]

It's a 4YB2 150 Yanmar in a 25R 2010 Ranger .... The damper/harmonic balancer/pulley had the center rubber bored out from the crankshaft when my alternator seized up and caused the belt to stop which made the pulley stop but energy from the engine was still turning crankshaft which then bored out the center of the pulley! ....We did take engine out and put new alternator and damper/HB/pulley back on! FYI The bolt that holds the pulley on has an enormous amount of torque on it so you will need a four foot extension with about 200 lbs of pressure being delivered at your end of the extension in order to deliver enough energy to break the bolt loose! To tighten it down the manual says 74lbs of torque , then a torque angle of 60 degrees, another 60 degrees, and then a final 30 degrees! I was told this would figure out to be around 800 lbs of torque on the bolt?? NEVER USE AN IMPACT WRENCH ON THIS BOLT AS IT WILL DAMAGE INTERNAL BEARINGS!