Sorry just first saw this response. 1. - Kill wires pulled, first 2 coils went bad possibly bad SAM, upgraded to new CD ignition system. 2. Have to remove the engine to check, don't feel it's pertinent at this time 3. Carb is on the way 4. May apply after I install new OEM carb. 5. Head gasket was torqued but not lapped, possible after new carb installed. 6.Free flow at the carb was tested after the new fuel pump was installed but not as a long term test. Could setup after new carb installed. 7. didn't have the bolt so I removed the rubber end and cut the shaft off. 8. Not doing any more with these carbs. 9. New ignition does not need to be gapped, actually there is not provision in the mounting holes to allow adjustment.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Kohler cv16 Command only runs with partial choke
- Thread starter teseal
- Start date
More options
Export threadWell I guess it's not the carb, got the OEM unit today and it did not do any different, in fact it appear I had to hold the choke closed a bit more for it. I also noted sometimes a spit of gas out the carb.
When I removed the spark plug also noted that is was black and carbon coated, engine has only run for minutes since I cleaned it last. Not sure what that says if the plug looks like it's been burning rich, maybe just because it has never warmed up very much.
Of coarse I don't have a leakdown tester but I did jury rig something, pressurizing the cylinder (didn't have a gauge with small enough increments to measure the cylinder pressure) with my air compressor regulator set at 50, and 100' of hose it dropped to about 35. I did not hear air leaking back thro the carb as expected nor thro the exhaust. Seems all the air was back thro the crankcase.
Question: Could bad rings or worn cylinder account for the symptoms where it appears to run lean????
When I removed the spark plug also noted that is was black and carbon coated, engine has only run for minutes since I cleaned it last. Not sure what that says if the plug looks like it's been burning rich, maybe just because it has never warmed up very much.
Of coarse I don't have a leakdown tester but I did jury rig something, pressurizing the cylinder (didn't have a gauge with small enough increments to measure the cylinder pressure) with my air compressor regulator set at 50, and 100' of hose it dropped to about 35. I did not hear air leaking back thro the carb as expected nor thro the exhaust. Seems all the air was back thro the crankcase.
Question: Could bad rings or worn cylinder account for the symptoms where it appears to run lean????
Last edited:
Sounds lean again.got the OEM unit today and it did not do any different, in fact it appear I had to hold the choke closed a bit more for it.
Cam issue/timing or some issue in the valve train.I also noted sometimes a spit of gas out the carb.
Now we are running rich.When I removed the spark plug also noted that is was black and carbon coated
It does I agree but I think I been barking up the wrong tree, I feel like I'm back to square one with my original question; What does a rich mixture help overcome and allow it to run? Here's one more thing I kind of forgotten about, after the first go around replacing most of the fuel system including the carb the engine did run without a choke for about 30 minutes while I played with it. Next time I tried to start it the present problem became apparent. Shortly after that the ignition failed.Sounds lean again.
Possible valve issue is what brought on the leakdown jury rig test. The manual says these engines all have the auto compression release system, so the 60psi I got for compression would be invalid. The leakdown test I did didn't indicate a valve seating issue but I'm not taking that to the bank either.Cam issue/timing or some issue in the valve train.
How can the plug say rich and the symptoms say lean?Now we are running rich.
Guess I really don't know where to turn.
Last edited:
Engines can run rich and still run okay. To a point after that you start fouling plugs and losing power. Too lean makes more HP and runs hotter. 14.7:1 is what they call stoich or optimum/middle range for mpg and clean burning plugs. Most mowers run a tad rich. Most plugs have black on them when you look at them. So there is a range engines can run it and be happy. Call it like 12:1 to 16:1 for example. So many parts air and so many parts fuel.What does a rich mixture help overcome and allow it to run?
Leak down test should be done at TDC with the valves closed I think. Haven't done one in a while. Maybe one of the others can chime in here with the exact procedure.
Something is foul with yours. You've done all the basics. Probably time to pull a valve cover and watch the valves move up and down. Both should get pressed down into the block the same amount. Might even get to see the ACR working or not. Pull the plugs and watch the valves move.
Wondering if your cam is suspect??
Engines can run rich and still run okay. To a point after that you start fouling plugs and losing power. Too lean makes more HP and runs hotter. 14.7:1 is what they call stoich or optimum/middle range for mpg and clean burning plugs. Most mowers run a tad rich. Most plugs have black on them when you look at them. So there is a range engines can run it and be happy. Call it like 12:1 to 16:1 for example. So many parts air and so many parts fuel.
Leak down test should be done at TDC with the valves closed I think. Haven't done one in a while. Maybe one of the others can chime in here with the exact procedure.
Something is foul with yours. You've done all the basics. Probably time to pull a valve cover and watch the valves move up and down. Both should get pressed down into the block the same amount. Might even get to see the ACR working or not. Pull the plugs and watch the valves move.
Wondering if your cam is suspect??
Yeah leakdown at TDC so both valves are closed, didn't have the monitor but at least could listen for air to escape.
I'll could check the valve movement but don't know what to expect with the ACR, I thought it opened the exhaust valve early. (?)
With all that's been done with the carb I think it can be eliminated as the culprit.
I would guess the gas "spitting" is for some reason expected on this engine and that's why the air filter assembly includes a "spit cup" as it's called to catch the gas.
I didn't check the flywheel pin suggested earlier because there's alot to disconnect with the horizontal shaft but I will when I remove the engine.
Head is torqued as specified just wasn't honed, not sure of the effect by not doing so, did have a new gasket.
Cam is gear driven so I don't know how the valve timing could be off. I do know both valves were closed at TDC and both lifters are working. Any way to check without major disassembly? ( remember this thing did run for about 30 minutes OK, or let's say at least without choke, I wouldn't say good because it did fluctuate slightly but that may have been related to the goofey generator spring.)
The blacken plug after only firing for a couple of minutes sure is confusing.
Open to any and all suggestions, I'm out of ideas here.
I would guess the gas "spitting" is for some reason expected on this engine and that's why the air filter assembly includes a "spit cup" as it's called to catch the gas.
I didn't check the flywheel pin suggested earlier because there's alot to disconnect with the horizontal shaft but I will when I remove the engine.
Head is torqued as specified just wasn't honed, not sure of the effect by not doing so, did have a new gasket.
Cam is gear driven so I don't know how the valve timing could be off. I do know both valves were closed at TDC and both lifters are working. Any way to check without major disassembly? ( remember this thing did run for about 30 minutes OK, or let's say at least without choke, I wouldn't say good because it did fluctuate slightly but that may have been related to the goofey generator spring.)
The blacken plug after only firing for a couple of minutes sure is confusing.
Open to any and all suggestions, I'm out of ideas here.
Again I catch myself calling my problem child a CV when in fact it is a CH.
Anyway just wanted to update everyone and many thanks for all the suggestions. Sorry I can’t tell you what it is that does not allow my Kohler CH16 to run without the choke partially on but I can tell you what it wasn’t, also something surprising I had learn. It was not related to anything in the fuel system from the gas tank to the intake manifold.
I didn’t know where to turn with the CH16 so I ended up acquiring a CH13 that hadn’t been used in 3-4 years to replace it. The carb on the 13 was corroded beyond repair and need to be replaced so I took the OEM carb from the 16 and installed it on the 13. The fuel pump when tested free flow at the carb at first didn’t pump because I think the steel gas line portion that passes thro the blower housing was partially plug. Cleaned the steel line and tested, pumped ok free flow at the carb. Seem to run ok once I got it started so I closed it up and tested the tractor. The governor may be a bit slow but otherwise seemed ok, at least it was running without the choke. Next day when I wanted to use it, it started hard and would not run. It would pop off and run for 5 seconds then slowly die. Gas flow? There was particles in the float bowl so I attacked the steel line again. This time installed a filter between the carb and line just in case. Tested but got the same result, would start and run a few seconds then slowly die. The choke did nothing to help it run. Noticed there was no gas in the filter I added by the carb. When the engine was cranking over with the starter some gas trickle thro but once the 13 started the flow stopped, shortly after so did the engine. I replaced the fuel pump with the pump from the CH16, left the filter install just in case, used the tractor all afternoon without a problem.
Lesson learned; free flow test for the fuel pump is not conclusive, once there was a bit of back pressure from the carb the pump stopped. I did disassemble the fuel pump and the valves looked ok.
Anyway just wanted to update everyone and many thanks for all the suggestions. Sorry I can’t tell you what it is that does not allow my Kohler CH16 to run without the choke partially on but I can tell you what it wasn’t, also something surprising I had learn. It was not related to anything in the fuel system from the gas tank to the intake manifold.
I didn’t know where to turn with the CH16 so I ended up acquiring a CH13 that hadn’t been used in 3-4 years to replace it. The carb on the 13 was corroded beyond repair and need to be replaced so I took the OEM carb from the 16 and installed it on the 13. The fuel pump when tested free flow at the carb at first didn’t pump because I think the steel gas line portion that passes thro the blower housing was partially plug. Cleaned the steel line and tested, pumped ok free flow at the carb. Seem to run ok once I got it started so I closed it up and tested the tractor. The governor may be a bit slow but otherwise seemed ok, at least it was running without the choke. Next day when I wanted to use it, it started hard and would not run. It would pop off and run for 5 seconds then slowly die. Gas flow? There was particles in the float bowl so I attacked the steel line again. This time installed a filter between the carb and line just in case. Tested but got the same result, would start and run a few seconds then slowly die. The choke did nothing to help it run. Noticed there was no gas in the filter I added by the carb. When the engine was cranking over with the starter some gas trickle thro but once the 13 started the flow stopped, shortly after so did the engine. I replaced the fuel pump with the pump from the CH16, left the filter install just in case, used the tractor all afternoon without a problem.
Lesson learned; free flow test for the fuel pump is not conclusive, once there was a bit of back pressure from the carb the pump stopped. I did disassemble the fuel pump and the valves looked ok.
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 64
- Messages
- 24,705
The CH mechanical fuel pump can be a problem.
Over time the cam lobe that powers it wears round so after a while it can not supply enough fuel for prolonged full speed running
Very deceptive as at cranking speed you get good fuel flow.
From way back when I went mad chasing up an "overheating / electrical " problem that was doing the same to some 2000 series Cubs and found the actual problem was a plug of grass clippings in the fuel tank I learned to check everything.
So when I get a problem like yours I jerry rig an old 1 gallon tank frome a SV Tecumseh, fit inline spark testers then go mow .
Once we got all of the Cubs tanks cleanned they remained relatively trouble free till one would start to miss a bit after running .
One of the fuel pump diaphragms failed so we fitted a new one and I tested the volume pumped at cranking speed and was amazed just how much more the new pump shifted .
so now it is an annual test, time taken to fill a 200 ml cup and as it gets longer & longer I schedule a pupp job and if that does not cure the poor fuel flow then it is a new pump cam job
FWIW it takes the pump3 minutes to fill the 200ml jug ( spark plug removed of course )
From memory ther is a time listed in the Kohler manual .
Over time the cam lobe that powers it wears round so after a while it can not supply enough fuel for prolonged full speed running
Very deceptive as at cranking speed you get good fuel flow.
From way back when I went mad chasing up an "overheating / electrical " problem that was doing the same to some 2000 series Cubs and found the actual problem was a plug of grass clippings in the fuel tank I learned to check everything.
So when I get a problem like yours I jerry rig an old 1 gallon tank frome a SV Tecumseh, fit inline spark testers then go mow .
Once we got all of the Cubs tanks cleanned they remained relatively trouble free till one would start to miss a bit after running .
One of the fuel pump diaphragms failed so we fitted a new one and I tested the volume pumped at cranking speed and was amazed just how much more the new pump shifted .
so now it is an annual test, time taken to fill a 200 ml cup and as it gets longer & longer I schedule a pupp job and if that does not cure the poor fuel flow then it is a new pump cam job
FWIW it takes the pump3 minutes to fill the 200ml jug ( spark plug removed of course )
From memory ther is a time listed in the Kohler manual .