PDA

View Full Version : what all could cause x-rich black..Kohler 25.


mowisme
04-12-2008, 12:07 AM
I ran the Kohler today to move it..It now has a steady miss and steady dry black 'soot' out the exhaust? covers my tie with a dry black powder..like you'd get out of a fire place. Would this be: 1)carb 2)lifter's bad 3) bent push rod 4) loose rocker..these seem to be the trouble spots for this engine- Thanks -Geno P.S. The new coils have .012 air gap.

Mic_bug
04-12-2008, 10:35 AM
I ran the Kohler today to move it..It now has a steady miss and steady dry black 'soot' out the exhaust? covers my tie with a dry black powder..like you'd get out of a fire place. Would this be: 1)carb 2)lifter's bad 3) bent push rod 4) loose rocker..these seem to be the trouble spots for this engine- Thanks -Geno P.S. The new coils have .012 air gap.

choke stuck


raw fuel from missing cyl

VegetiveSteam
04-12-2008, 11:16 AM
What is the engine model number?

mowisme
04-12-2008, 03:27 PM
The engine is a CV25S. The black 'soot' is not wet at all- black powder like. I meant to say in original post..covers my 'Tire', not 'Tie- I don't wear my Sunday best when working on mowers. Anyway- use to miss after warmed up..now misses almost from start. I don't think any 'unburned' gas is coming thru exhaust as it is dry black powder, not wet. Same on plugs. Seems VERY rich. I have tried cleaning carb - seemed like new inside. The choke is 'wide' open. I'm wondering if it could be 'Spark advance'?? I also don't think it is head gasket as that would create 'Lean' not rich..am I right on that? Any/All help appreciated. oh..would bad oil ring cause 'DRY' jet-black powder? Geno

VegetiveSteam
04-12-2008, 03:38 PM
It could be the spark advance module but probably not. Don't see too many problems with that analog spark advance module anymore. One thing to check is the flywheel key. They don't shear very often on these types of engines but I have seen it. Especially if it ever afterbangs or runs on when you shut it off. That can partially shear the flywheel key and it doesn't take much of a dent in that key for the engine not to run well. To check the key you have to take the flywheel completely off. It is a woodruff key and without taking the flywheel off you can't see if it's sheared or dented. If you are going to check the key make sure you use a proper flywheel puller and do not hammer on the top of the crankshaft. If you do you just might find that you now have excessive crankshaft end play as hammering on the flywheel end of the crankshaft and cause the gear on the crankshaft to move.

mowisme
04-12-2008, 04:36 PM
good thought Veg...and thanks on advice on removing flywheel. I won't do it without a proper puller..don't need more problems. Thanks- Geno

MowerMedic77
04-12-2008, 06:48 PM
Any chance you could post the spec# of the engine? I was thinking you may have a bad accelerator pump but would need the spec# to know if your engine is equipped with one.

VegetiveSteam
04-12-2008, 07:32 PM
Good point Medic. Shame on me for not thinking of that.

Mow...look on the side of your carburetor and see if there is a metal cover with 3 screws in it and a vacuum hose connected to it. There could be two vacuum hoses on it. If you have that on your carb pinch off or disconnect the one of the vacuum hoses and see if that changes your rich condition. If it does you have a bad pump diaphragm like Medic said. If that turns out to be the case you have two options. If you don't notice any transition issues from low to high speed and no hesitation when you get into deep grass you can simply leave the vacuum hose pinched off. If you disconnect it make sure you plug the hose securely. You don't want to pull any dirt into the carb. If you do notice a problem with hesitation then you'll need to change the diaphragm. Be forewarned though. That kit could be in the 70+ dollar range.

mowisme
04-12-2008, 08:45 PM
the only hose is the one by air cleaner base going to canister above valve cover (PVC?..or..it just has filter foam in it)- I got it covered up out in rain right now so can't get spec# at this time..but am sure no vac hose going to carb. Had it off couple times. This motor appears to be a 'early' one as bit of crud on it at base..guess that don't tell thou.

mowisme
04-14-2008, 03:47 PM
Well I took the flywheel off- The woodruff key looks fine. I may have a Accelerator pump after all- I knew there was only one hose going from carb to engine (PCV) BUT..today noticed there is a plate on left of carb as you are looking at it from the front (air cleaner end). this plate has three screws and is semi-cone shape and has a small hose going to top of carb near intake flange..is this a accelerator pump? (I know what acc pump is on older car carbs)- thanks - Please let me know ASAP as I am leaving shroud off until I eliminate that possibility. Gene (I will see if OM shows that on carb)

mowisme
04-14-2008, 03:57 PM
I checked manuel..definately have the Acc-pump. I noticed there was/is a adjustment screw right in center of pump diaphram that is accesiable from outside of carb..that I believe is screwed way in..if not completely? I'll see if I can figue out way to adjust..or do as said and try pinching off. Geno

caseymax
04-14-2008, 06:29 PM
Why do you wear a tie? To start a 25hp Koler. you could not wear it the next time and your problem is solved. HA HA:laugh:

mowisme
04-14-2008, 10:34 PM
Ya..I know..I missed a 'key' when writing the post- kind of like you did when you spelled 'Kohler'..'Koler'- but little fun helps the frustration so I'll try it tomorrow without the tie on..Now do you got any Logical Ideas of the problem? Geno

mowisme
04-14-2008, 10:37 PM
I pinched the vac hose off to accelerator pump..did no different. I tried to adjust low speed mix screw on top of carb..That also changed nothing. Still covers the tire with DRY black carbon from muffler. Thinking a 'new' carb is in order. Geno

FIXDISS
04-15-2008, 01:35 AM
When you start it again try pulling plug wire on one side then the other to see which one is "missing". Once you determine that then you might want to remove rocker cover on that cylinder and look for a bent pushrod,loose rocker assy mount bolts ,a valve spring or keeper problem or even a valve sticking open.My guess would be exhaust valve side not seating properly for one of the above reasons. Just my half-fast opinion.

MowerMedic77
04-15-2008, 12:42 PM
I pinched the vac hose off to accelerator pump..did no different. I tried to adjust low speed mix screw on top of carb..That also changed nothing. Still covers the tire with DRY black carbon from muffler. Thinking a 'new' carb is in order. Geno

Pull the three screws on accelerator pump and inspect the diaph. inside, if it is all distorted then you will need a kit for the pump, your carb is fine. Post your model and spec# and I can get the part # for your kit. I think there is only one kit(24 757 56-S) but still post your #'s to be sure.

mowisme
04-15-2008, 05:30 PM
thanks MM77- here's the numbers: CV25S
spec. 551310
ssn. 2626212817