Small Engines (Lawn Mowers, etc.): Simplicity Broadmoor runs weak under load, gas filter, hydraulic valve

Question
I have a Simplicity Broadmoor Hydro 14 lawn tractor with a Kohler CV14S engine Serial No. 2500421324. The engine power drops off significantly when the deck is engaged and some black smoke comes from the exhaust. When the deck is not engaged it runs fine, even at full speed up hills. The deck blades spin freely and are routinely greased. I have replace the air filter and gas filter. At first I had trouble starting it and it would backfire but then I removed and cleaned the spark plug as it was dirty with a thin dark film. It started right up. I have the correct 10W-30 oil in the engine. I have not done anything with the carb yet. Can you give me some ideas on what may be wrong and how I might correct it? It was running strong earlier in the spring.

Answer
John

Have you checked the deck belts to make sure nothing is binding.Also you may have to adjust the valves. Or you may hydraulic valve which adjust by themselves.Have you checked the fuel pump , to see if it is pumping full volume to the carburetor? It could be not keeping up with the fuel demand. It seems to be a problem with the fuel supply, meaning the fuel tank, the lines, pump, or the filter and last, the carburetor.

The diagram on the carburetor shows an electric fuel shutoff solenoid. Have you removed it and removed the working tip and tested with it out of the system?You can test by turning the key on not start it just turn it on you should hear a click from the solenoid

The Fuel solenoid is affected by voltage drops, that makes me think it could be problem, when you engage the blades, the voltage drops and when you disengage the voltage rises again.

More likely a bad solenoid. I would remove it and see if the working end, the plunger won't come out. Then replace the non working solenoid and test. They serve no useful purpose, they are put on so the engine won't backfire when it shuts off.