Cub 1450 - Pressure Sound on Shutdown

thefickler · #1 06-02-2015, 10:20 PM

Hey guys,

I'm wondering if anyone has ran into the issue that I experienced tonight. I have tried to search for some possible answers, but I'm not even really sure what to search for, and I didn't find any results This is what I noticed....

I used my 1450 today for a bit, and when I parked it and shut it down, when the engine was finally done spinning, I could hear some pressure being released. Or something that sounded like it. I couldn't pinpoint where the sound was coming from, so I started it back up, let it run for like 15 seconds and shut it back down. I noticed the same sound of pressure escaping from somewhere for like 5 seconds.

Does anyone have any idea as to of what this could be? I'll have to pull the panels tomorrow and see if I can hear it any better, but I just wondered if someone has experienced this before. Thanks for any help,

zippy1 · #2 06-02-2015, 11:55 PM

It would likely be the carburetor.

Berwil · #3 06-02-2015, 11:56 PM

Do you have a deck/tiller with a belt on the pto? If no, could it have been a spinning sound? If I don't have the deck/thrower belt on the pto, my pto pulley spins down when I shut the engine off. The pto brake that keeps the pulley from spinning when no pto belt is installed is out of adjustment. It needs to be adjusted with the spring loaded nuts that hold it on per the manual. It doesn't affect performance (safety perhaps) so it's been low on my list to fix.

If it's not that.....I got nuthin

Bill

cub cadet 72 guy · #4 06-03-2015, 01:28 AM

I think that's from the heat and the carb. Maybe gas evaporating from the heat?

J-Mech · #5 06-03-2015, 04:33 AM

More than likely, you have a good engine and you are just hearing the compression push past the rings and into the crankcase and out the vent. The engine stops turning when it hits the last compression stroke that it can't "push" through, so it always stops with pressure in the cylinder. What you are hearing is actually good news.

Only other thing that crosses my mind is a leaking head gasket, but you would most likely hear that when it was running.

It's not the carb.

R Bedell · #6 06-03-2015, 05:18 AM

Could be the ACR disengaging and hearing the compression pressure release through the exhaust.

ol'George · #7 06-03-2015, 08:05 AM

I second the spin down of the pto, if no belt on it. BTDT, but just my guess

thefickler · #8 06-03-2015, 08:26 AM

That's what I thought too, that it could be the compression, however I have never noticed it before until last night. It currently has no mower deck or anything on it, so that couldn't be any of the noise.

I also thought it could be the ACR, but I still don't know why else it would be making the sounds that its making now. It's just odd that I haven't ever heard this noise before. I'll take a closer look tonight and see what I can find. Thanks for some of the feedback guys.

zippy1 · #9 06-03-2015, 11:43 PM

Quote:

Originally Posted by J-Mech

More than likely, you have a good engine and you are just hearing the compression push past the rings and into the crankcase and out the vent. The engine stops turning when it hits the last compression stroke that it can't "push" through, so it always stops with pressure in the cylinder. What you are hearing is actually good news.

Only other thing that crosses my mind is a leaking head gasket, but you would most likely hear that when it was running.

It's not the carb.

I be darned. All this time when I hear that "hoosh" sound on my 1650, I thought it was coming out of the carburetor. Well Jon, I'm in the general area anyway....
And I've got "a good engine"

J-Mech · #10 06-04-2015, 05:36 AM

Quote:

Originally Posted by DoubleO7

if you are hearing the front pto spin to a stop from the seat, you need to replace the bearing in it.

I disagree. Could just be the friction disk.

I don't think it's the PTO anyway....

Quote:

Originally Posted by zippy1

I be darned. All this time when I hear that "hoosh" sound on my 1650, I thought it was coming out of the carburetor. Well Jon, I'm in the general area anyway....
And I've got "a good engine"

Well, you could hear the noise from the carb..... but it wouldn't be the carb. Maybe an intake valve that isn't closed all the way, or not sealed good bleeding compression pressure out the carb.... but that's not the carbs fault.

OP:
If you aren't using the PTO (PTO driven equipment attached) you should leave it on. It's hard on the button/clutch thro out mechanism to run the engine with it disengaged and no load (belt) on it to keep it from spinning. Even the owners manual says that IIRC.

I'm still sure your hearing compression air releasing and it's nothing to get concerned about, but it's good to check things out if the noise is new.