782 cub cadet ignition or carb problem

[MinnesotaFarmall]

I've got a 782 gas with the Kohler KT 17. I've used it to now lawn and blow snow and haven't had this issue before. My daughter used it to do the local garden tractor pull and it will blow black smoke and stumble terrible. I've installed new points, set correctly and have sent through this carb with a microscope. I'm not sure what's going on but she can putt around the yard all day without any problems. Soon as it gets a good load like the sled behind it, it spits and sputters and blows black like the choke is stuck on. I'm thinking I got to change the condenser out and see. It's been finiky with it before. Thoughts or opinions?

[snoshoe]

Been 30 years or more since I messed with a KT. I would think weak spark. If it has the plastic coil bolted to the intake manifold. That would be my first suspect. Would check plugs and wires first. Especially where they plug into coil.

[560Dennis]

Did you clean the new points ? There is an oxidation protection coating on them. My not be the problem ,but pulled against a guys that didn’t do that and they were pretty frustrated with the problem an engine .

I only use Kohler points at the start of every pulling season. I clean the points as the instructions state.

may repeated other comments 

few other things I thought of eating breakfast 

the carburetor float level with the black smoke. Check it with gasket or without ,not familiar with that kt17 carburetor 
the float is it leakin . full of fuel ,check it .

Test the needle and seat ,are they sealed ?

is the choke adjustment actually open the butterfly valve all the way? Is butterfly loose? 
check carb vents wholes are they open ?

Is the carb to intake gasket sealed , no leaks at gaskets ?

got bright spark plug heat range in there ?

 

 

 

[snoshoe]

I have a whole list also like valve clearance head gaskets crankcase pressure vent soaking air cleaner. Thought just start with most likely. I didn't think condenser was likely but admit it is possible. 

[HydroTek]

Ya do know that the point gap is set using a light and the mark on the flywheel ?? -- right 
-- that sets the timing for the spark 

With the engine revved up -- Hi speed screw turned in until the carb throttle just starts to open a little -- then back out 1/4 turn ??

Both plugs fire at the same time on that engine 
-- have seen a few with burned connection inside the plug wire boot 

[Sparky]

6 hours ago, HydroTek said:

Ya do know that the point gap is set using a light and the mark on the flywheel ?? -- right 
-- that sets the timing for the spark 

I have a KT17 series 2 in mine and I've heard that, too. Never been able to figure out how to do it yet. I just set the points and roll on. 

I fell for the Kirk Engines "points saver" several years back. Never could get the engine to run right, started hard, wouldn't stay running. Figured out the "points saver" was the problem. Contacted Kirk Engines and never heard a word from them.
 

I run a GM coil pack on mine, too. No way am I spending what they want for a Cub Cadet coil.

 

Travis

 

[MinnesotaFarmall]

59 minutes ago, Sparky said:

I have a KT17 series 2 in mine and I've heard that, too. Never been able to figure out how to do it yet. I just set the points and roll on. 

I fell for the Kirk Engines "points saver" several years back. Never could get the engine to run right, started hard, wouldn't stay running. Figured out the "points saver" was the problem. Contacted Kirk Engines and never heard a word from them.
 

I run a GM coil pack on mine, too. No way am I spending what they want for a Cub Cadet coil.

 

Travis

 

How do you run the gm coil pack? I don't think coil is my problem because it will run literally all day long with no hiccups until I hook it to the sled and it gets a real load behind it. Will mow lawn, cruise around, out and idle and the whole shabang without any issues until it gets hooked to the sled.

[MinnesotaFarmall]

7 hours ago, HydroTek said:

Ya do know that the point gap is set using a light and the mark on the flywheel ?? -- right 
-- that sets the timing for the spark 

With the engine revved up -- Hi speed screw turned in until the carb throttle just starts to open a little -- then back out 1/4 turn ??

Both plugs fire at the same time on that engine 
-- have seen a few with burned connection inside the plug wire boot 

No I haven't done it that way. I have used a feeler gauge for setting points. I have done it that way with an old rotax engine though.

[MinnesotaFarmall]

9 hours ago, snoshoe said:

I have a whole list also like valve clearance head gaskets crankcase pressure vent soaking air cleaner. Thought just start with most likely. I didn't think condenser was likely but admit it is possible. 

Wondering if the air filter could be my problem. Vent is puffing a bit so I don't think it's clogged. The engine is a very healthy engine with no head gasket issue at all. It also fires right off with barely a revolution of the key. It will run all day long until it gets hooked up to the sled and it needs every last h.p.

[MinnesotaFarmall]

11 hours ago, 560Dennis said:

Did you clean the new points ? There is an oxidation protection coating on them. My not be the problem ,but pulled against a guys that didn’t do that and they were pretty frustrated with the problem an engine .

I only use Kohler points at the start of every pulling season. I clean the points as the instructions state.

may repeated other comments 

few other things I thought of eating breakfast 

the carburetor float level with the black smoke. Check it with gasket or without ,not familiar with that kt17 carburetor 
the float is it leakin . full of fuel ,check it .

Test the needle and seat ,are they sealed ?

is the choke adjustment actually open the butterfly valve all the way? Is butterfly loose? 
check carb vents wholes are they open ?

Is the carb to intake gasket sealed , no leaks at gaskets ?

got bright spark plug heat range in there ?

 

 

 

Yes cleaned the points upon install. Sand paper, but of alcohol on a piece of paper to clean off the grit.

Carb is set correctly. It runs great, will mow lawn, no issues, pull a garden trailer, no issues. I set the float so it is a bit high when carb is inverted. So the float isn't quite parallel to the carb body but slightly pointed up per only cub cadets . Com sight.

First thing I checked was choke. It's opening all the way up.

Carb gasket is good because I checked it with ether to see if rpm changes. Did not change. 

Spark is great, it will jump almost a quarter inch with my spark tester. 

[snoshoe]

1 hour ago, MinnesotaFarmall said:

Wondering if the air filter could be my problem. Vent is puffing a bit so I don't think it's clogged. The engine is a very healthy engine with no head gasket issue at all. It also fires right off with barely a revolution of the key. It will run all day long until it gets hooked up to the sled and it needs every last h.p.

Wasn't thinking of clogged. Was thinking more of EGR and oiling of filter. Disconnect vent and hook to your heavy load to test. Remove filter and do it again to test that.

Need to know more about spark test. Was it to engine ground or spark plug terminal? While cranking or engine running? Still thinking weak spark or borderline lean. Strongly suggest you check valve clearances if you don't find anything else. A leak down test might be in order. Poor man's version is turning engine by hand while listening at open carb and muffler. Takes a contortionist sometimes or help

[HydroTek]

Muffler shield in good shape ??

not blowing hot exhaust back on the carb or intake ?

That mower blows the exhaust out the front grille 

I run that engine in my saw mill 
that one gets the snot pulled out of it sometimes 

I put a KT17 in my 169 Cub Cadet several years ago 

[560Dennis]

So when you pull it at the track is the engine warmed up to temperature or are you getting in line and  hooked and pull ?

 

added this ? 
Spark jumps a 1/4 inch , that should be 3/4 of an inch on my tester for small engines . 

[HydroTek]

Spark jumps both plugs at the same time in that engine

so spark is "grounded" thru the plug that is not making power 
-- the plugs are connected in series

would shorten the spark gap some 

[560Dennis]

What octane fuel you using to pull ,with ? 
two much and it won’t burn changes timing 

check exhaust temperature 

[MinnesotaFarmall]

13 hours ago, snoshoe said:

Wasn't thinking of clogged. Was thinking more of EGR and oiling of filter. Disconnect vent and hook to your heavy load to test. Remove filter and do it again to test that.

Need to know more about spark test. Was it to engine ground or spark plug terminal? While cranking or engine running? Still thinking weak spark or borderline lean. Strongly suggest you check valve clearances if you don't find anything else. A leak down test might be in order. Poor man's version is turning engine by hand while listening at open carb and muffler. Takes a contortionist sometimes or help

I have a spark tester that you screw in and out to adjust the gap test. I set it at 1/4" and clip it to an unpainted piece of metal on the engine. I think it was part of the intake on one side and the fin by the spark plug on the other. I don't think it can be lean because it's smoking black when it acts up. 

[MinnesotaFarmall]

12 hours ago, 560Dennis said:

So when you pull it at the track is the engine warmed up to temperature or are you getting in line and  hooked and pull ?

 

added this ? 
Spark jumps a 1/4 inch , that should be 3/4 of an inch on my tester for small engines . 

Yes engine is warm.

[MinnesotaFarmall]

12 hours ago, HydroTek said:

Muffler shield in good shape ??

not blowing hot exhaust back on the carb or intake ?

That mower blows the exhaust out the front grille 

I run that engine in my saw mill 
that one gets the snot pulled out of it sometimes 

I put a KT17 in my 169 Cub Cadet several years ago 

All shrouds are in good shape. 

[snoshoe]

6 minutes ago, MinnesotaFarmall said:

I have a spark tester that you screw in and out to adjust the gap test. I set it at 1/4" and clip it to an unpainted piece of metal on the engine. I think it was part of the intake on one side and the fin by the spark plug on the other. I don't think it can be lean because it's smoking black when it acts up. 

The black smoke is the fuel from your misfires partially burning in the exhaust system.

[snoshoe]

Single cylinder K's would stick the exhaust valve when hot. Not enough experience with the twins but I imagine it is possible here too. Again check valve clearance. Exhausts tend to wear tighter and make them run hotter. Aggravates the problem.

[HydroTek]

40 minutes ago, snoshoe said:

Single cylinder K's would stick the exhaust valve when hot. Not enough experience with the twins but I imagine it is possible here too. Again check valve clearance. Exhausts tend to wear tighter and make them run hotter. Aggravates the problem.

Same -- just two singles in one engine 

[MinnesotaFarmall]

8 hours ago, 560Dennis said:

What octane fuel you using to pull ,with ? 
two much and it won’t burn changes timing 

check exhaust temperature 

91 non ethanol. 

[MinnesotaFarmall]

The only thing that gets me is that it only does it when hooked to the sled. It will run literally all day long and never have a hiccup until it's hooked to the sled. It's when it achieves full load. I can mow grass as tall as the hood and it doesn't bother just when it's getting it's full work out constantly. 

[PJW360]

Lots of help above one thing not mentioned exhaust muffler is muffler starting to get blocked causing a restriction but not so much it’s allowing it to run fine under normal conditions

[560Dennis]

4 hours ago, MinnesotaFarmall said:

The only thing that gets me is that it only does it when hooked to the sled. It will run literally all day long and never have a hiccup until it's hooked to the sled. It's when it achieves full load. I can mow grass as tall as the hood and it doesn't bother just when it's getting it's full work out constantly. 

Do you have kill switch ?