CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)

winmod21

Active Member
Joined
Aug 12, 2021
Threads
3
Messages
75
  • / CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)
How I pressure test a float carburetor is invert the carburetor; usually with fuel bowl off. Attach a pressure line to fuel inlet and pressurize 5-10 psi using my pressure/vac tester. With the system pressurized wait 30 minutes to see if the standing pressure drops.

As Leak down tester and an oil pressure tester those are usually reserved for shops. I think in the last year I have used my oil pressure tester twice before the current repair job but I will need it again once I replace the oil pump to verify that I resolved the oil pressure lost issue on the Kawasaki motor. Of all things they B/O the pressure regulator spring.
Thank you, StarTech !;-) I guess that's something I'll have to skip then, as I don't have a 'pressure/vac tester', nor do I have a 'pressure line', but only a Makita 3 Gal compressor these days, although it does dial down very accurately to low pressures. And I only have the standard 3/8" air hoses w/the quick-connect fittings on their ends. I suppose I could jerry-rig something, but how do you attach 1/4' fuel line to a standard compressor air hose? Anyhoo, sounds like I had best pass on that test !
 
Last edited:

winmod21

Active Member
Joined
Aug 12, 2021
Threads
3
Messages
75
  • / CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)
Save yourself some time and inevitable injury and get it to a qualified service facility.
It's starting fine when cold; runs super great, never even sputters, in fact, it seems to run better now than when it was brand new!
All it's doing.... is not restarting after being shut-off and while still warm. So hardly a need to take it to a service facility, until after I've done several of the typ troubleshooting procedures myself.
 

winmod21

Active Member
Joined
Aug 12, 2021
Threads
3
Messages
75
  • / CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)
This is why we discourage people tacking a "me to' on the bottom of an old thread.
It just confuses every one
I was fairly sure I had fully answered your questions
but please have a little think
1) engine will not run with the bowl removed from the carb because the main jet will not be imersed in the fuel
So you do the on engine test while cranking the engine using the battery, spark plug removed so you do not overload the starter.
2) as Star has already outlined, you do the pressure test with the carb off the engine as it has to be upside down so the weight of the float is closing the valve
Most fuel pumps will pump between 5 to 10 psi so the valve has to be able to with stand that pressure
And I am in Australia so way different time zones
I view the forum on a computer & do so while having breakfast and occasionally when using the computer to research parts or write invoices
So some days I might drop in 20 times & other days only once
Add to that I do have a life so was off for 3 days motorcycling

Please download the Kohler service manual and do a basic service
This includes CLEANING the carb & setting the valve lash
Throwing parts at an engine in the hope that you will luck in a solution is a good way to compound your problem an empty your wallet .
I just about urinate in my trousers from laughter with all the posts that start with "I have changed to oil, oil filter , spark plug & air filter but......"
as if changing the oil makes any difference to a problem other than having no oil
In 300 odd services a year I replace about 5 spark plugs and find about 2 air filters so badly clogged that the mower will not start unless it has been tipped over & the filter is full of oil .
Copy that. I haven't done anything yet. It fired right up yesterday like it was brand new; ran beautifully, not even a sputter, seemingly, as I mentioned above, even better than when it was new. But then, as before, it wouldn't start after I shut it off to blow all the grass off before backing it into the garage. Same as last weekend. Although after it sits for awhile, cooling down, in yesterdays' case....all week, it fired right up - with a wee bit of choke.

I did d'load the Kohler Service Manual last summer, so will read-up on how to set the valve lash, as I have no idea how to do that.
Don't recall anything in the service manual about how to clean the carb, but I did take it off last year when I was replacing the air filter inlet (ABS black plastic inlet), but only sprayed the outside w/carb cleaner & shot some into it both ways as well, which did seem to help. I haven't taken a carb apart--to clean & rebuild--since the 80's. 😬 But I will, I guess, if you insist 🧐...as we did purchase one of those ultrasonic cleaners last week (haven't used it yet, so can return it - if recommended not to use), and picked-up some Simple Green concentrate yesterday. Notwithstanding I did read that you prefer the stovetop method, and have a slam-bang recipe for doing so?

Btw, I suppose it'd be a good idea to buy & download the JD 'Technical Service Manual' [TM1756] as well.
 
Last edited:

VegetiveSteam

Well-Known Member
Joined
Jun 1, 2022
Threads
0
Messages
446
  • / CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)
It's starting fine when cold; runs super great, never even sputters, in fact, it seems to run better now than when it was brand new!
All it's doing.... is not restarting after being shut-off and while still warm. So hardly a need to take it to a service facility, until after I've done several of the typ troubleshooting procedures myself.
Not trying to be mean here but you don't know how to do any of the troubleshooting procedures and from the sounds of it your mechanical abilities are next to nothing. You are going to hurt yourself. Working with carburetors and fuel is very dangerous if you don't know what you are doing. Don't wait until you're standing next to a burned down garage with your mower in the middle of it and most of your hair gone to take it to a professional.
 

winmod21

Active Member
Joined
Aug 12, 2021
Threads
3
Messages
75
  • / CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)
Not trying to be mean here but you don't know how to do any of the troubleshooting procedures and from the sounds of it your mechanical abilities are next to nothing. You are going to hurt yourself. Working with carburetors and fuel is very dangerous if you don't know what you are doing. Don't wait until you're standing next to a burned down garage with your mower in the middle of it and most of your hair gone to take it to a professional.
Not trying to be disrespectful here but you sure don't know whatever the hell you think you're talking about. I've already done several of the "troubleshooting procedures", as well as replaced entire engines. So "from the sound of it"....your reading skills and assumption abilities are "next to nothing"!
I've also never hurt myself, whether working on tractors or trucks. While I've never claimed to be any kind of expert or pro with engine mechanical services or repairs, contrary to your asinine assumptions, my mechanical abilities are actually quite good, in fact, easily above average, thank you very much.
Nonetheless, I'm quite aware of all the dangers associated with working with fuel. I was simply inquiring about a test procedure that I haven't done and didn't know about; that doesn't mean I was definite going to try to do it; just meant I was curious about it, and trying to assertain if it was a test that I may want to try, or not. As I don't take things to 'professionals' unless I absolutely have to; never have, never will.
Back in the 1980's, when I lived & worked on a 47,000+ acre cattle ranch, when we weren't pushing cattle, or building log bunkhouses & ranch houses, or hay barns, or mending miles & miles of fence lines, or working on tractors or combines or balers or haytools or spreaders or forage equipment &c, or shooting predator cougars or coyotes during calving seasons, or Grouse gunning over our Llewellin Setters, or deer or elk or bighorn sheep hunting, or building fly-rods & fly-fishing, we sometimes worked on our trucks. We had a 47' Ford pickup completely restored, except for replacing the Flat 8 with a Ford 283 out of a 65' Galaxy 500, and replacing the double-clutch tranny with a (T100?) from a 67' 1/2 ton Ford pickup. Also had a 48' Ford F-1, 51' Mercury M, and 52' Ford F-2; of which I rebuilt the carbs on each, the tranny on one, and replaced a lot of other parts on all of them, such as intake & exhaust manifolds & drivelines & suspension & steering parts &c. During the early to mid 80's, I think (13) or (14) of the 45'~47' Fords (no production during WWII) were offered to me for free, for parts, by several Ranchers & Farmers, if I wanted to haul them off, as the 1/2 ton pickup body was the same as the 2-1/2 ton bodies on the big farm & ranch trucks with 18~20 ft flatbeds. Btw, I bought all three (the 48', 51' & 52') from the original owners!....while upland gunning for Sharptail & Sage Grouse.

Moreover, if I didn't know what I was doing....I would've just started messing around with the carb a few weeks ago, without knowing what I was doing, instead of taking the time to come to this great website —whilst patiently asking questions over several days— about our non-restarting issue when the engines' warm. Apparently you've forgotten that that's also one of the main reasons for the existence of this website.
So why don't you run along and try to find someone else to insult and get frosty with, Ol' Sport.
 
Last edited:

VegetiveSteam

Well-Known Member
Joined
Jun 1, 2022
Threads
0
Messages
446
  • / CV15S start=sputtering, backfire, surging. Fuel off=runs great then dies (obviousy)
Not trying to be disrespectful here but you sure don't know whatever the hell you think you're talking about. I've already done several of the "troubleshooting procedures", as well as replaced entire engines. So "from the sound of it"....your reading skills and assumption abilities are "next to nothing"!
I've also never hurt myself, whether working on tractors or trucks. While I've never claimed to be any kind of expert or pro with engine mechanical services or repairs, contrary to your asinine assumptions, my mechanical abilities are actually quite good, in fact, easily above average, thank you very much.
Nonetheless, I'm quite aware of all the dangers associated with working with fuel. I was simply inquiring about a test procedure that I haven't done and didn't know about; that doesn't mean I was definite going to try to do it; just meant I was curious about it, and trying to assertain if it was a test that I may want to try, or not. As I don't take things to 'professionals' unless I absolutely have to; never have, never will.
Back in the 1980's, when I lived & worked on a 47,000+ acre cattle ranch,
when we weren't pushing cattle, or building log bunkhouses & ranch houses, or hay barns, or mending miles & miles of fence lines, or shooting predator cougars or coyotes during calving seasons, or Grouse gunning over our Llewelin Setters, or deer or elk or bighorns sheep hunting, or building fly-rods & fly-fishing....we repaired tractors and trucks. We had a 47' Ford pickup completely restored, except for replacing the Flat 8 with a Ford 283 out of a 65' Galaxy 500, and replacing the double-clutch tranny with a (T100?) from a 67' 1/2 ton Ford pickup. Also had a 48' Ford F-1, 51' Mercury M, and 52' Ford F-2; of which I rebuilt the tranny on one and replaced a lot of other parts on all of them. Btw, I bought all three (the 48', 51' & 52') from the original owners!....while upland gunning for Sharptail & Sage Grouse.
Moreover, if I didn't know what I was doing....I would've just started messing around with the carb a few weeks ago, without knowing what I was doing, instead of taking the time to come to this great website —whilst patiently asking questions over several days— about our non-restarting issue when the engines' warm. Apparently you've forgotten that that's also one of the main reasons for the existence of this website.
So why don't you run along and find someone else to insult and get frosty with, Ol' Sport

My assumptions were created when you asked about running the engine with the float bowl off which pretty much took all the assuming off the table. I will make another assumption and assume your original question the way you asked it wasn't exactly what you meant to ask and wish you the best of luck. IMHO though you are barking up the wrong tree with the carb being the issue but then my reading skills could be lacking. I will say as for cleaning the carb, an ultrasonic cleaner and Simple Green is about as good as you can get.
 
Last edited:
Top