Cub engine queston?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
smokinj

smokinj

Minister of Fire
Aug 11, 2008
15,980
Anderson, Indiana
Cant quite figure this out. Had no issue with the cub until yesterday. It now runs rough at wot and oil leak seems to be coming from the top of the fly wheel housing(Oil leak started two weeks ago)But just now started to run rough? Runs fine at idle to half throttle.
 
Jags said:
Jay - did you do piston/rings/cylinder work on this engine?
Click to expand...

No but I got great compression and will smoke a little when first started. Spark plug is dry. Ran great when I put it away last Sunday.
 
Before suspecting the worst, I'd check the breather assembly. These get gummed up on those K301's, and can cause some of the issues you describe. In fact, are you sure the oil is not leaking from the breather, itself?
 
  • Like
Reactions: smokinj
Joful said:
Before suspecting the worst, I'd check the breather assembly. These get gummed up on those K301's, and can cause some of the issues you describe. In fact, are you sure the oil is not leaking from the breather, itself?
Click to expand...

No I didn't have much time to check. I ran through the simple stuff. Spark plug wires and coil. Then I jump on the deere and finish the lawn.
 
The reason I ask is that it sounds like you have blow by (coming out the breather). That is usually a sign of rings. Does the plug look nice and dark tan or is it sooty looking?
 
  • Like
Reactions: smokinj
Jags said:
The reason I ask is that it sounds like you have blow by (coming out the breather). That is usually a sign of rings. Does the plug look nice and dark tan or is it sooty looking?
Click to expand...

Sooty looking.
 
smokinj said:
Sooty looking.
Click to expand...

Yeah - you are burning oil. The higher the RPM the more oil it will pump. Check your breather to make sure it isn't just plugged solid (and it might be), but I hate to break the bad news, it sounds like it is time to pull the motor apart.
 
  • Like
Reactions: MasterMech and smokinj
Will painting it green and yellow help? ;)
 
  • Like
Reactions: mithesaint and Ashful
Jags said:
Yeah - you are burning oil. The higher the RPM the more oil it will pump. Check your breather to make sure it isn't just plugged solid (and it might be), but I hate to break the bad news, it sounds like it is time to pull the motor apart.
Click to expand...

The compression seems way to high and the lack of smoke seem that the rings are at least in ok shape wouldn't think?
 
smokinj said:
The compression seems way to high and the lack of smoke seem that the rings are at least in ok shape wouldn't think?
Click to expand...

Well...You would think so. It is possible for the oil ring to be shot, yet the compression rings are still doing their job. "Check the breather" is step number one.

Don't take me as the only voice of reason, hopefully we will hear from others, but K series Kohlers are about as simple as they get.
 
  • Like
Reactions: smokinj
Jags said:
Well...You would think so. It is possible for the oil ring to be shot, yet the compression rings are still doing their job. "Check the breather" is step number one.

Don't take me as the only voice of reason, hopefully we will hear from others, but K series Kohlers are about as simple as they get.
Click to expand...

I am not just throwing it out there. Rebuilding it not that out of the question. Wanting to repaint the whole thing anyways. I will check the breather and pull the head see whats up for sure first.
 
smokinj said:
I am not just throwing it out there. Rebuilding it not that out of the question. Wanting to repaint the whole thing anyways. I will check the breather and pull the head see whats up for sure first.
Click to expand...


Yep, see what kind of carbon is deposited on the head. A big build up of carbon can also cause pre-ignition at higher speeds.
 
  • Like
Reactions: smokinj
I don't think we've confirmed the breather is oiled up...could just be a failed seal.

If you were burning oil, it would smoke...a lot...and not just on startup. You might have a bad valve seal that make is smoke on startup. You might have a sooty plug because you are running rich. You might be leaking oil from the jug gasket and/or the crank seal. It might be running rough because you just now fouled the plug enough, or you might have a weak coil, or it might be starving for fuel, or....

That's a lot of mights. Figure out where that oil is coming from before you tear down the engine. Could be simple. Or it could be time for a rebuild.
 
  • Like
Reactions: smokinj
Another mention of the breather broke loose an old memory. I have actually had the internals on one of the breathers rattle loose. They do act as a one way valve, if this ain't working correctly, it can allow for leaks and actually cause weird stuff to happen.
 
  • Like
Reactions: smokinj
lukem said:
I don't think we've confirmed the breather is oiled up...could just be a failed seal.

If you were burning oil, it would smoke...a lot...and not just on startup. You might have a bad valve seal that make is smoke on startup. You might have a sooty plug because you are running rich. You might be leaking oil from the jug gasket and/or the crank seal. It might be running rough because you just now fouled the plug enough, or you might have a weak coil, or it might be starving for fuel, or....

That's a lot of mights. Figure out where that oil is coming from before you tear down the engine. Could be simple. Or it could be time for a rebuild.
Click to expand...

Oh yea....Best thing though about the 301 is the whole rebuild kit is under 75.00. Plus machine work probably another 50.00. But ti could just be a blown head gasket or clogged breather.
 
Jags said:
Another mention of the breather broke loose an old memory. I have actually had the internals on one of the breathers rattle loose. They do act as a one way valve, if this ain't working correctly, it can allow for leaks and actually cause weird stuff to happen.
Click to expand...

Gives me a good game plan.
 
  • Like
Reactions: Jags
Ok got the head off. Iamb seeing wet oil spots on the gasket. Could this be do to over filling oil?
 
Well, you already got the head off, but I would've changed the plug and if no change, check the points. (gap and condition)

Pull the air filter

Check to see if it responds to carb adjustments

Plugged breather would likely produce smoke while running and oil leakage at the gov shaft.

But since the head is off, check the piston for any noticeable lateral play @ TDC.
 
Yep your right if I wasn't through this thing already. Its very strong so that's what made me pull the head right away. Going to have it milled and new gasket. Just make it stronger either way. I GOT A GUY FOR THAT. Not sure that it but pretty cheap.
 
MM's suggestion of points is another area I would look at. I have also had a couple of condensers go bad, too.
 
Jags said:
MM's suggestion of points is another area I would look at. I have also had a couple of condensers go bad, too.
Click to expand...

There is fresh oil on the head gasket.
 
Just re-read the OP, and realized I was focused on the oil leak, not the running rough. Yeah, those points are severely heavy duty, for such a small engine, but they don't last forever!

I wonder, have you checked your RPM at WOT? Sure you're not severely over-reving? That's easy to do, given the hokey governor / throttle stop setup they have on those old Kohlers.

Oil on the headgasket... don't assume it's rings. These Kohlers seem to suffer bad valve guides before rings. That said, I'd still be changing that breather and running with that, before digging any further.
 
  • Like
Reactions: smokinj
Joful said:
Just re-read the OP, and realized I was focused on the oil leak, not the running rough. Yeah, those points are severely heavy duty, for such a small engine, but they don't last forever!

I wonder, have you checked your RPM at WOT? Sure you're not severely over-reving? That's easy to do, given the hokey governor / throttle stop setup they have on those old Kohlers.
Click to expand...

That would make since. Everything was fine when I put it up. Change the oil and problems started. The governor is just pop over and over.
 
Status
Not open for further replies.

Similar threads

Z
Just my luck
Replies
5
Views
146
DIY and General non-hearth advice
zrock
Z
P
Dodging a bullet with my heating system
Replies
0
Views
941
The Boiler Room - Wood Boilers and Furnaces
peakbagger
P
T
Smoke Starts Leaking Into Room All of a Sudden?
Replies
24
Views
2K
The Hearth Room - Wood Stoves and Fireplaces
Tiffany and Bartholomew
T
B
Chainsaw fouling plugs
Replies
17
Views
3K
The Gear
Isaac Carlson
Isaac Carlson
M
Help! Kozy Z42 burn times
Replies
4
Views
579
Kozy
Mustang
M
Top Bottom
Back