Kohler Courage 21hp starts, dies, won't start, runs fine

[packardv8]

Kohler Courage 22hp on Toro Timecutter 4235.

Choke on, it starts immediately, dies immediately. From then on, it won't restart without priming. A few drops of gas or a shot of ether and it will start immediately and run and idle fine. When hot, restarts immediately.

Why start then die? Why primed it starts and then runs fine? If the fuel system were empty, seems if the pump would take a few seconds to fill the system, but it doesn't. When primed, it's as if nothing is wrong.

What am I missing here?

jack vines

 

[mechanic mark]

Parts | Toro

www.toro.com

Locate your serial number & see Service Manual Troubleshooting Section, use OEM Toro Parts.

 

[Bertrrr]

Sounds like a fuel issue , start by looking at the filter first then supply lines that may be cracked or dry rotted then move on to the carb.
It is not an ignition problem so concentrate on fuel

 

[Tiger Small Engine]

Sounds like a fuel issue , start by looking at the filter first then supply lines that may be cracked or dry rotted then move on to the carb.
It is not an ignition problem so concentrate on fuel

I agree with Bertrrr. If it has fuel pump, pull line off of pump to carburetor, and make sure good spurts of fuel are coming out. If gravity fed tank, remove fuel line from tank and see if you have good steady flow. Take gas cap and blow it out with air compressor. Change fuel filter. If all that checks out and no change, onto cleaning the carburetor. If you don’t want to do all that, keep a can of carb spray handy to start.

 

[Yardman999]

My CH22 suffers from this too. One thing I did was to keep the fuel tank very full which decreases the pressure loss from the tank to the vacuum-driven fuel pump. I also learned that it did not like nonOEM fuel filters (too high a pressure loss?). The clear OEM filters, even before this problem, were always about one-third full, just full enough to have fuel entering its outlet (slopes down).

Not too many years ago I replaced all the fuel and vacuum lines, filter, pump, and OEM carb, and cleaned out the tank as well as pressure-tested the tank's dip tube. Still didn't solve it.

Yesterday, it was cold out, but the CH22 started fine. Then, while in high-idle, it died about 30 seconds later. And never would restart, but would fire briefly with starting fluid sprayed into the carb.

P.S. Just remembered: I once found that the short/thin rubber tube to the air filter housing (down to the engine?) was disconnected. IDK if reconnecting it helped.

 

[Yardman999]

Fixed mine! Turned out to be the (previously replaced, but years ago) vacuum-powered fuel pump. And fortunately I had a new (cheap) pump on the shelf.

But figuring out it was the pump took a while this morning. * Working on fuel is very dangerous, so leave it to professionals is my advice to most folk. *

Lots of head scratching so not done rapidly: 1) Disconnected pump's fuel output line, and it was dry. Attached a length the new hose and put it in a cup. Cranked the engine, and no flow.

2) Disconnected the pump's vacuum source hose, held my thumb over the hose end, and cranked the engine. No suction perceived. So followed the hose to the back of the engine and found no breaks (I had replaced all the lines not too many years ago). Thinking maybe either a big vacuum leak somewhere or a plugged port, line, etc. So then removed the air filter and its base plate, and checked the thin black plastic hose that has its exit just over the carb's inlet -- I'm guessing this is the ultimate source of vacuum (and the air filter must be installed to get it). No problem felt in that hose. More head scratching. Cleaned the free end of that hose, then blew hard into it. Pressure built well, though slight leaks from the oil dipstick and somewhere else, but I deduced not bad enough to be the problem. So installed a vacuum gauge in that previously disconnected line, cranked the engine, and observed a 0-to-high/rapidly fluctuating reading (so is good). Reconnected the vac line to the fuel pump thinking maybe I had cleared a blockage. But still no fuel flow.

3) So decided the fuel pump was likely bad. Disconnecting its fuel supply line (coming from the tank and the filter) revealed that the pump was full of fuel, to I'd guess its outlet (reed?) valve was shot. Installed the new pump, primed it via about 5 seconds of cranking, then the engine fired up smartly. The nearly 30 year old CH22 is running like a champ again!

 

[packardv8]

Thanks for the constructive suggestions.

I'd have already replaced the fuel pump if I thought it was the source of the start-die-no-start problem, but once started on the spray, the engine runs fine.

jack vines

 

[Tiger Small Engine]

Thanks for the constructive suggestions.

I'd have already replaced the fuel pump if I thought it was the source of the start-die-no-start problem, but once started on the spray, the engine runs fine.

jack vines

Pull hose from fuel pump to carburetor and crank engine. Needs to be a strong and steady pulse of fuel. If it dribbles, then remove and replace fuel pump. Usually is the fix, although, clogged fuel lines, blockages in tank, etc. do happen.