# YS624 blue oil leak



## blackis (Jan 7, 2019)

My YS624 has leaked oil for couple of seasons. Now i have to refill oil between every use.

Im thinking of fixing the leak after snow melts, but i do not know where the leak is coming from. Is there a common place for leak? Here is result after one hour of blowing snow:









Upper side of engine seems to be clean:









Is there a gasket set for rebuilding the engine?


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## dbert (Aug 25, 2013)

Disclaimer- I dont have much experience with Yamaha.
Curious what caused the crack that was welded to the component on the top forward piece.did whatever caused that crack transfer to the engine case in that location?
To pinpoint the source of the leak requires a really good cleaning of the old leaked oil.
I don't have it anymore or remember who made it, but after a good cleaning and drying an aerosol powder was applied to the suspect area. The initial wetting of the powder after very short runs would help determine the actual source


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## dbert (Aug 25, 2013)

Still not sure exactly what the function of this cracked bracket is, but I found another thread with the same crack.
Still doesn't necessarily help with the oil leak, but helps me understand what I am looking at.
My "New" Yamaha YS624 - Cleanup & Broken...


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## groomerz (Feb 7, 2015)

Looks like it may be leaking from the cover gasket above the oil fill. Are any of the screws


Sent from my iPhone using Tapatalk


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## ST1100A (Feb 7, 2015)

It probably has a main seal leak. Remove the flywheel and check the crank seal, they have been known to leak there from the seal blowing out. It will then blow back to the back of the engine from the cooling air and drip down all over the place.
Check the crank seal behind the pulley on the PTO side also.
Check your crankcase cover bolts for tightness as they can come lose and it will leak from the cover gasket.


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## JnC (Feb 21, 2014)

That cracked bracket is a common issue with older Yamahas that have rubber engine mounts. The real early ones i.e. mid~late 80s models were solid mounted to the chassis like most snowblowers, later models (especially the 828s) switched to engines with rubber mounts. This helped a lot with reduced vibrations but the front bracket seems to crack due to fatigue. 

Looking at the pictures it seems like your issue is a loose bolt and bad crankcase gasket. This could happen due to the vibrations, I have ran into this issue with the GX motors found on the Honda machines. Usually re-torquing the crankcase cover bolts helps but if the leak is severe enough I just install a new gasket. 

I'd try to torque those crankcase bolts first, 17.2 or 18 ft/lb is the torque on most M8 bolts, confirm it with the service manual first, if this doesnt help then change the crankcase gasket.


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## blackis (Jan 7, 2019)

Today was wet snow. After working for two hours ,oil level dropped half centimeter. I toor the belt guard off and looked if I couls apot the leak. The belt guard inner side is covered in splashed oil. Heres images


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## JnC (Feb 21, 2014)

Looks to be bad main seal for the crank/output shaft. 

If done properly you wont even have to remove the engine off of the motor to replace it. 

Take the pulleys off. 
Screw in a drywall screw at 12 and 6 o'clock, screw them in only enough so you can use leverage to pull the seal out. Or you can use a seal puller. 
Put on the new seal, push it in as much you can and then tap it in using a pipe with the same OD as the OD of the seal. A bit of tape on the contact area of the pipe would ensure you dont damage the new seal. 
Put the pulleys back on and you should be good.


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## orangputeh (Nov 24, 2016)

my Honda leaks red oil.....


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## blackis (Jan 7, 2019)

JnC said:


> Looks to be bad main seal for the crank/output shaft.
> 
> If done properly you wont even have to remove the engine off of the motor to replace it.
> 
> ...


Thank you  do you know the correct oil seal part number?


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## JnC (Feb 21, 2014)

Item # 23 in this diagram, part number
*93102-25090-00*












looks like this











if you cant find Yamaha part then dimensions are following, a standard high temp seal with these dimensions will suffice. 


* 25x40x5 (IDXODXWidth)
*


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## blackis (Jan 7, 2019)

Ok, ordered the part from france for 13 euro including posting.


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## blackis (Jan 7, 2019)

So i changed the main pto seal. It was a pita to take out, had to drill two small holes in the old seal, the put screws in and with those screws, it came out. I put the new one in, so i thought everything is now ok.

Today it snowed so i took the beast out. After blowing i notived the oil level was lower again. Not as much before but still lower. So i took the pto plastic cover off. It was clean inside, so main seal is not leaking.

I then cleaned the whole front of the engine with brake cleaner and started the beast again. Here is result:






I tried to tighten the brass colored 10 mm wrench bolts, but that did not help. So I think the cover gasket is faulty. What is the part number, anyone know? And if you could give detailed instructions on how to change that.


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