Cub Cadet 1650 - governor or carb issue

[dhermesc]

I bought a Cub Cadet 1650 that had been sitting for a LONG time. I bought it a year ago and I am guessing it sat (in a shed) for 5 to even 10 years before I bought it. I don't think this engine has a lot of hours on it as it had always been an in-town yard unit just mowing the homeowner's yard. Has fresh engine and transmission oil. All 4 tires were flat, the deck was heavily rusted and the spindles on the deck barely moved. The blades on the deck were lightly worn and getting them off was a chore. This summer I finally started working on it. New battery cables, new coil, new spark plug and wire, flushed the fuel tank, new fuel line, new starter solenoid, starter switch, new seat - etc... I pulled the valve cover and gapped the valves - the intake was almost right but exhaust valve was in need of adjustment. I cleaned the carb a couple times. But even spraying starter fluid through it I couldn't get the old Kohler to even fire. Finally pulled it - and dropped on a cheap Chinese carb for $15. I also only filed the points (not replaced) - they appear to be in good condition.

Engine now starts fairly easily - a second or two on the starter with the choke pulled and it fires up.

The issue is when I mow - yesterday was the first time I tried mowing with it.

If the engine pulls down (governor kicks in) it immediately starts to stumble and cut out. Even after shutting down the deck, it continues to miss, sputter and occasionally backfire. With the PTO shut off if you pull the throttle to idle it will smooth out and start running correctly again. If you don't pull the throttle back to idle it will continue to sputter and miss and will die. The cub will immediately restart as if everything was fine. Rev it up, kick in the PTO and it runs fine until it pulls down again and goes back through the process of missing and sputtering.

I am wondering if I have it running to lean and when the governor kicks in it there isn't enough fuel getting to the engine. Or could this be the governor not working properly? I do know when I first installed the new carb it was running extremely lean and the engine wouldn't idle.

Now the engine seems to run strong and runs from idle to wide open (no load) with no hesitation or other issues.

 

[Blackhole49]

All the governor does is open the throttle plate (sounds like what yours is doing). Sounds like still a carb issue to me. Try partial choke when it starts to draw down and see if it helps.

 

[dhermesc]

Put a working carb on from a 1450 - Cub does the exact same thing. When the engine is cold it runs fine and will respond to the governor without an issue. Once its warmed up - does the stall thing when the governor kicks in. The warmer the engine gets - the worse the stall issue becomes. With the engine "hot" it even starts stumbling without the governor kicking in hardly at all.

Could this be the condenser or possibly the coil? I know the coil is "new" - not necessarily a guarantee its good. I believe I may have left the old condenser on the engine.

 

[T.R.K.]

You did check the flow of fuel through the fuel line didn't you? To see if you are getting a good flow not just a dribble. What kind of fuel filter did you install? Is it a small engine fuel filter or automotive? Some automotive filters are made to work with fuel pumps and don't flow enough fuel unless under pressure. ( I am thinking your 1650 does not have a fuel pump.)
Try another condenser, it can't hurt. If you have access to another coil, try it as well.
Also, try a different wire between the points and the coil. I have seen two of those engines where the wire between the points and coil was grounding/arcing in the metal clip. You do have the condenser on the same terminal on the coil as the wire to the points, (-) don't you? And the condenser body needs a good ground, too.
You did make sure the points were clean and properly gapped, didn't you? You can start with .020 gap. There is a procedure in the manual to adjust them with a timing light in the manual.

 

[timcasbolt]

Put a working carb on from a 1450 - Cub does the exact same thing. When the engine is cold it runs fine and will respond to the governor without an issue. Once its warmed up - does the stall thing when the governor kicks in. The warmer the engine gets - the worse the stall issue becomes. With the engine "hot" it even starts stumbling without the governor kicking in hardly at all.

Could this be the condenser or possibly the coil? I know the coil is "new" - not necessarily a guarantee its good. I believe I may have left the old condenser on the engine.

I've run into something similar with a bad head gasket.

 

[dhermesc]

Figured it out.

I had made sure that I installed the new coil exactly the same way the old one was removed. The wires were reversed. The keyed wire was on the negative and the wire from the points and the condenser were on the positive. Reversed the wiring and it runs perfect now. With the Chinese carb it runs strong - but I notice the choke slowly starts to close after running a while. A couple times it seemed to start losing power but adjusting the choke to wide open solved the issue. Mowed for about 15 minutes the let it sit and idle for a while (another 20 minutes) and hopped on it and opened up the throttle - run good but did blow a little smoke. I may run it an hour or so mowing and change the oil again.

The other issue I have is the keyed switch and connector were horribly corroded. I replaced the switch and tried to clean the factory connector but it still looked pretty rough. I've had a couple issues with starting and I reach through the hydrostat slot on the dash with a screwdriver and push/wiggle the connection and it works. I think I might cut the factory connection off and replace it with three female slide terminals. I hate messing/splicing with factory wiring but I also don't want to deal with it not starting for anyone.

That may explain why it was parked for so long. The owner installed a coil and reversed the wiring, and it never ran right again. As I said it looked like it had set for as much as 10 years. They had another John Deere mower that looked to be from the 1990s (LX188) they had been using.

 

[T.R.K.]

Those insulated spade connectors should work fine. If you are keeping records on the machine, it may be helpful in the future if you make a sketch of which wire goes where on the switch.

 

[560Dennis]

So there’s nothing wrong with the originals carburetor,right ?

 

[dhermesc]

So there’s nothing wrong with the originals carburetor,right ?

The engine wouldn't fire with the original carburetor - even when using starting fluid. It would start easily with the cheap Chinese carburetor and run until the engine got warm. The original carb needs rebuilt at minimum - and rebuild kits cost more than complete carburetors.

 

[Don B.]

Id still put the old carb on. Even if I had to rebuild it first. Even if the passages inside are completely blocked it should have fired in gas or starting fluid sprayed in the inlet side. Putting the Chinese wannabe carb on didn't fix your machine.

 

[dhermesc]

Running fine now with the Chinese carb. Not interested in making issues that don't exist.

 

[Don B.]

"making issues that don't exist"?? Huh