KT series 2 problem
 

Yesterday, I got the 782 that I mow with, out to mow. Everything was good for about 5 minutes. Then the thing started to act like it was running out of gas but still had half a tank. It stopped but I was able to get it going again by pulling out the choke I milked it back to the shed by pulling the choke in & out. In the shed it seemed to run OK with the choke in at full throttle & then at half throttle but at idle it would shut off. If I would move the throttle down to the point were it would still run & not shut down the rpm's would go up & down Up & down but still run. I did take it back out & finish mowing but kept it a full throttle it seemed fine. But to try idle it would still shut down or just above idle the rpm's would be up down up down. This engine has always run great for me until now. I never had a new one but I couldn't imagine new running any better than this did. It has about 5 hours on a new set of plugs, oil change,& air filter. I did pull the plugs & the left side plug looked to burning perfect the right side plug looked to be sort of black not the same as the other. I pulled a spark plug wire from my other 782 & tried it on the right side but no change on how it runs.

Since pulling the choke helped it stay running I'm going to say its a fuel problem and has nothing to do with spark, if you had a spark problem choking it wouldn't help. Sounds to me like it has some trash in the carb that's plugging it up, probably time to rebuild the carb and flush the fuel system.

One thing I did not mention when I did the Spring service I pulled the gas tank An installed a new fuel shutoff with the screen. Good I did the old screen was very dirty An there was a cap off the end of a gas can that was rolling around in the tank. But that was my first thought a carb problem just didn't think that could happen so fast with no warning

All it takes is one small chunk of crap to get in the carb and its all over, generally you don't get much of a warning. Did you replace the fuel lines? Its possible that the line is coming apart inside and the carb is sucking up chunks of rubber.

Easy to get a crud in there from the fuel line when disturbing it.
Might take the carb off and remove the bowl, and have a look see.
while in there blow out any/all passages/jets.
If you are lucky you will not damage any gaskets.
But if so, they are easily obtained.

I did replace the one line from the tank with new also added a in line filter but did not replace the other line. Since I am far from a small engine wiz is there some type of carb cleaning additive that would help?

Carb cleaner additives don't work very well if at all, best bet is to take it apart and clean it. Make sure your fuel filter is flowing good, some filters have to much restriction to work properly on a tractor engine.

How is your oil level and how does it smell? My thought is fuel pump took a dump, those engines are famous for that. My 782 I used to have did that and had the exact same symptoms.

Just went out & checked oil level is just a little below full mark & it smells the same as my other 782 meaning I didn't smell gas in the oil if that's what you mean. Think I am going to try to pull the carb. This will be a new one:bigthink:

Hey, it was worth a try! :biggrin2:

I'm just trying to think of things that would make it run ok at full throttle but not at idle. Good carb cleaning, new fuel line, and cleaning the tank would be where I'd start. If it runs at full throttle it's not a fuel restriction in that sense but I'd think something may be in the "idle jet" (can't think of what it's technically called :bash2:). If not fuel pump, I'd wager dirty carb :beerchug:

If the two plugs didn't look the same you may have an issue with the cylinder that the plug was more black. If it has a intake valve issue, that would cause the fuel mixture to be off and jacking with the choke would help. It is possible that is an issue with the carb, but being that it runs fine at WOT but not at idle and that it happened suddenly, I'm betting it's a cylinder issue. You can look into it (the carb) if you want, but I don't think your going to find anything. More than likely your going to pull the head on the side with the black spark plug. On another note, it is possible that it is a spark plug issue. What plugs did you use (Brand and number)?

I used champion rv17yc & the right plug definitely is different color than the left

Check and make sure you have good spark on both sides. If so, do a compression check. There is no compression release on these motors.

Ok so I did go out earlier & attempt to remove the carb but I ran into trouble trying to get the throttle linkage removed from the carb. So I just stayed calm & put it all back together. I did notice a very small gas leak at the fuel line & the fuel pump. I installed new fuel line there. I started the thing up & ran it at half throttle for about 15 minutes. It now runs good at full & half & even does idle but just a bump up from idle the rpms still jump up & down. I can check spark but at this point I have no way to check compression

O'Rileys or Autozone will rent you a compression checker at no charge.

Just checked spark it is the same at both sides. I will need to purchase a compression checker but not time for that today. Thanks for every ones help

Fuel pump going south? Mine would start to run erratic and when I pulled the choke out it would smooth out.

It's possible.
In this case the plug color not being the same has me wondering...
It is also possible that there are two problems.

Hope to get my compression tester tomorrow but I have paper work from po an I did find this. Work was performed 7/11/13 hope the pic shows well

common problem with a common repair, why do you need a compression tester for a probable fuel issue ?

Just trying to have all the bases covered. Plus its something I should have in the future if I wont to keep these things running. Plus after looking at the invoice I would think there should be no problems with the carb. I HOPE

One bank is running richer than the other. I suspect low compression on one side. I suggested testing compression.

If that carb has an idle mixture screw, I'd try to adjust the low speed and see if the engine would smooth out.

If it seems to be running well now, I'd shut the hood and not worry about it. You might look at the plugs again and see if the coloring is now the same side/side.

Forgetting about it or ignoring a problem will not fix it.

The carb runs both cylinders, so the only way one side can run differently from the other if there is a problem with it. It won't just "get better" by adjusting the carb.

He said it appears to be running well now and will idle. That's why I suggested checking the plugs to see what they look like.

I can see you wanting to recommend another big money repair here on a 30-35 year old engine.:bash2:

You do it your way and I'll do it mine. Thanks.

I haven't recommended a repair as of yet. Just a compression check, which is pretty cheap. Might save him $$ later.


Yep, you do it your way and I'll do it mine. Meanwhile I'll try to save this guys motor for him while you tell him to just ignore it. Who's really helping? :Unknown:

My bet is you will wind up wasting his money.

What are you going to tell him if he spends the $$$ for a compression gauge and and finds has low readings? Spend more $$$$ for a rebuild on a 30-35 year old engine?:biggrin2:

Or what if he pulls the plugs and now, since the engine appears to be running much better, the coloring is closer to correct and consistent, side/side? Apparently he fixed something when he put the new gas line on because the engine is running better. If it turns out this be the case, then it's time to ignore his former issue.

That is what I said, not what you said I said.

Could have a bad head gasket on one side. OP can probably borrow a comp tester from an auto supply store. I didn't read that J-mech is suggesting that the OP spend big bucks, maybe I missed something? I seem to recall that he usually recommends doing a re-power rather than spend a lot of $$$ on these old engines. Carry on. :biggrin2: :beerchug:

Hey I said that first! :biggrin2: :beerchug:

That's what I'm betting. Cheap fix.


Yep. Unless it's a K series. Then we fix it. :biggrin2: :beerchug:

Could have but a blown head gasket that causes problems like this won't fix itself.

He said his running problems had basically disappeared except for a little idle problem and that can indicate a blown head gasket.

That's why I suggested adjusting the idle mixture screw and then checking the plugs.

If it is a head gasket, it'll get bad enough the OP will know it without even checking the compression with a gauge.

Never said a thing about ignoring the problem.

So what's your problem with sticking a gauge on it now to see if there is an issue and getting it fixed? Seems to me like the smart move.... :Unknown:

I can't for the life of me figure out what your arguing about here. Do you really think that a 15 min compression check is a waste of time??? This argument is absurd.

I'm not arguing about anything. If you don't like my responses, just don't respond to them. I just don't like your condescending attitude and responses toward another members post that has been working on engines, decades before you were born and your arrogant responses to other posts I've made. I'm not the only one that feels that way.

I've got about 25 or more CC's. They all run, they all cut grass, push snow, blow snow, till, plow or whatever else they're supposed to do. I don't ever take them to a mechanic to have them worked on. Never have. Never needed to. And remember, they all do what they're supposed to do so I kinda' have an idea I know what I'm doing.

You refuse to accept anything that doesn't go by the book because that keeps you out of trouble as a business man. I refuse to go by the book if I think there is an alternate way, better way, cheaper way, of accomplishing the intended goal.

I know what the books say. I've read a lot of books and I've made a lot of repairs over the decades and I've made my share of mistakes. But that's how I learned.

Got it? If you haven't got it, get it!

This thread is getting out of control, I suggest that it get back on track.

I am not posting to it any longer. Just going to watch it.

Ok with all that being said. I did a compression check. I did this with the throttle fully open & the choke open. Left side clean burning side 79 psi. Right 80 psi. I also checked the Kohler service manual & they said you should not have any thing under 90 psi. So it looks like this thing is getting tired. I will say it does not smoke at all while running or at start up. I did mow with it Sunday for about 20 min. it ran good just rough at idle. I don't know if it did anything when I replaced the other fuel line or not. Maybe it had some kind of junk in the carb that passed through if that's possible I don't know. With the compression where it is wonder how much time is left.

Been in your situation with a M18 having low compression like that. I think others will agree: looks for a repower and use it until it quits. Unless you sink boku bucks into it there is no saving that engine. Use it until it dies then repower with another M18 or Command or similar :beerchug:

Well, now is when we try Bon-ami bar cleaner. :)

Review post #23.

But check out the carb while you're at it and recheck the color on the plugs.

Engine clearances an compression readings and other specs are spec'd for a fully serviceable engine that will run a lifetime or hours without service. How many hours do you need out of that engine? Sounds like it will run a long time yet.

keep in mind all gauges have a + or - of accuracy , I wouldn't be condemning it off of the readings you have. there's hi quality gauges and cheap ones. is it using oil? check crankcase pressure is another test that can be done , compare your gauge to a known good one? even a tired motor can run good