[Dajawho]

Changed oil and filter today, along with spark plugs. Tractor had been running rough at initial start-up, so I thought plugs might be the first thing to try. I have a whole story to tell about the engine, running rough, etc... but this message is already gonna get too long!!!

1) I found the engine compartment much dirtier than its ever been... lots of oil/dirt residue near the top of the engine (rocker covers, etc.), moreso on the left side, which is the side with the dipstick and the fill tube. I had a suspicion that the oil level was too high before replacing it (based on dipstick indications), which was confirmed when I measured the drain oil... capacity is supposed to be 1-1/2 Qts, drain oil was at least 1-3/4 Qts. I think I got overly-ambitious awhile back when I checked and topped off the oil level. Could the dirty compartment be due to too much oil, thus it was being forced out somewhere? If so, where would it most likely be coming out???

2) After new plugs, engine seems to run better. However, when looking down into the throttle body (this is a fuel-injected engine), I swear I see fuel sorta "running" or "rippling" on the top of the butterfly. Is that how fuel is introduced... via the throttle body, on top of the butterfly? Its not necessarily "flowing" excessively, but it sure looks suspicious to me (a novice).

3) The butterfly, regardless of whether the engine is at low idle or high idle, is barely open. The only time the butterfly opens to any significant amount is temporarily, during throttle change... and even at that, the butterfly movement looks to be controlled by vacuum (?) or something OTHER than directly coupled to the throttle cable. Is this normal?

4) I can feel a lot (opinion) of crankcase air movement when I put my hand over the oil fill tube (with the cap off, of course!). Its not all positive... it seems to sorta balance out (almost like its reproducing the two cylinders pumping) with pressure and vacuum. With reference to my car engine experience (which isn't a great deal), I didn't expect to feel this air movement. Is this (any amount of detectable pressure and vacuum) normal?

I know, guys (and ladies), lots of questions... but I would appreciate your input on any or all of my four subjects!

 

[Mark / Ohio]

You appear to have a Kawasaki twin engine on that. Here's the information Deere shows for it:

Specifications

Unfortunately my experience with Kawasaki engines is zip. But I won't let that stop me from adding a few thoughts.

1)...Could the dirty compartment be due to too much oil, thus it was being forced out somewhere? If so, where would it most likely be coming out???

As engines get older like a car they do tend to weep some oil from around the gaskets. One common place would be around the crankcase vent hose which is usually located around the valve cover area and connects back into the intake manifold or air filter.

2) After new plugs, engine seems to run better. However, when looking down into the throttle body (this is a fuel-injected engine), I swear I see fuel sorta "running" or "rippling" on the top of the butterfly. Is that how fuel is introduced... via the throttle body, on top of the butterfly? Its not necessarily "flowing" excessively, but it sure looks suspicious to me (a novice).

I don't know that I would worry too much about that unless it is still running poorly. Do both cylinders seem to be firing or could it be running on one cylinder? Sometimes it is kind of hard to tell on the twins without pulling one plug wire at a time and seeing if the engine speed and sound changes.

3) The butterfly, regardless of whether the engine is at low idle or high idle, is barely open. The only time the butterfly opens to any significant amount is temporarily, during throttle change... and even at that, the butterfly movement looks to be controlled by vacuum (?) or something OTHER than directly coupled to the throttle cable. Is this normal?

Along with the throttle cable the governor also maintains the engine speed. The butterfly will only open just enough required to hold speed set by throttle cable. If you could look at the butterfly while burying it in 12" high grass you would see it open up a lot wider automatically. Otherwise the engine would stall. That probably has a spinning weight governor that is inside the crankcase. The other govenor style used on small engines is the air vane type. It uses the force of air movement from the cooling fan to detect engine speed.

4) I can feel a lot (opinion) of crankcase air movement when I put my hand over the oil fill tube (with the cap off, of course!). Its not all positive... it seems to sorta balance out (almost like its reproducing the two cylinders pumping) with pressure and vacuum. With reference to my car engine experience (which isn't a great deal), I didn't expect to feel this air movement. Is this (any amount of detectable pressure and vacuum) normal?

Some is normal. In fact they use those vacuum pulses on some engines to operate the fuel pump.

 

[Dajawho]

Wow, great reply and info. Thank you!