My 1st Cubs - 682 & 782
 

Hey guys, I got these in a trade recently and they're my first cub cadets. I've been a mechanic for years and have tinkered with garden tractors in the past, but never any cubs.

The 782 runs (pretty well actually), but has a TON of blow-by......

I haven't gotten around to getting the 682 running yet.

Welcome to OCC!
What engine is in the 782?

Thanks, It's a 17 HP KT Series II

Welcome to OCC!

The 7 is nice. The 6 is rough. Looks like a frog..... :biggrin2:

Maybe the engine in it is good...


How do you know it has blow-by? Vent should go into the air filter. Maybe the reed valve is broken..... :bigthink:

According to the guy I got them from... the engine in the 6 is good, time will tell I suppose.

On the 7, I took the oil cap off while it was running..... it nearly got blown out of my hand as the last thread came off.... it's bad lol.... It has nearly as much air puffing out of the oil fill as it does coming out of the exhaust pipe. I'm actually surprised at how smooth and "normal" it runs considering.......

Otherwise the 7 is in good shape for it's age.... straight sheet metal, everything works well (hydro lift, pto, trans, etc), and it's all complete.

Ok.... well.. that's normal. You can't pull the oil cap off a non PCV engine and not expect that to happen. Completely normal. I'm sure it's fine.

Oh ok..... I mean, I knew it would have some.... but this seems excessive. Hopefully it's not, hopefully it is a normal amount. I'm heading out of town tomorrow, but I will try to remember to post a video of it when I get back.

Thanks!

I assure you it's normal. Blow by is checked at the vent hose that is fed into the air filter housing. If it's excessive it will blow a lot of oil into the air filter. Some oil is normal. But a soaking amount is not. No need to take the oil cap off anymore to check it. It's a horizontal opposed engine, man. Both pistons move to the center at the same time, and move apart at the same time, so crankcase pressure spikes, them drops. It's normal.

https://www.youtube.com/watch?v=Pn89AXnNzaE

It's not that I don't believe you, or that I want to argue with you..... I just have never seen an engine, in my 20+ years of working on all shapes and sizes of them as a profession, have this amount of blow by considered "normal". Normal for an old tired engine with worn rings maybe.....

Anyway, if it is in fact "normal" for a good condition engine......great, score for me I suppose. I absolutely don't know and haven't seen everything.... so I very well can be wrong.....and, again, hopefully I am.... Hopefully this video confirms that this amount is perfectly normal and nothing to look twice at.

Thanks,
Lee

Ok. Yeah, that does seem excessive. Your right. In my defense, most questions on this board come from people with no idea what is or is not normal.

They do blow alot out running though..... I may go fire one up and see. Been a while since I ran one with the cap off....:bigthink:

I'm pretty sure that thing has a knock in it. Obviously it's a video and I'm not there, but pretty sure I hear it. That much blow by, a knock.... I'm betting on broken or burnt piston. Do a compression test. If your one of those guys who believe in a leak down test, do that too. I bet you find the cause pretty quick. Smoking quite a bit too unless it's just super cold in your garage...