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Discussion Starter · #1 ·
Hi, I have a Craftsman garden tractor with a Kohler twin cyl. engine- # CV20S, 20 H.P.

I had some gas that had trash in it and now the engine won't idle well. However, when mowing the lawn under full throttle it runs fine. I blew out the fuel filter, but no constant idle.

I'm thinking of a carb kit from Sears, but is there a way to clear up this problem without taking the carb off? I'm not sure what else to check.

All feedback is appreciated. :confused:
 

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What is the spec number off your engine??

It probably does not need a kit, but may have some debris in the low speed circuit of the carburetor, or a plugged pilot jet (depending on which carburetor your engine has).
 

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Discussion Starter · #3 ·
What is the spec number off your engine??

It probably does not need a kit, but may have some debris in the low speed circuit of the carburetor, or a plugged pilot jet (depending on which carburetor your engine has).
I have Kohler-#1205001, mod.- #CV20S, & Type- #65561.
 

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You may want to drop the float bowl and have a look to see if there is any debris collected in there. If there is, then a good cleaning may be in order. You can likely clean out the carburetor without using any parts. You should be able to drop the float bowl with the carburetor mounted, but you will have to remove the air filter assembly.
 

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Discussion Starter · #6 ·
You may want to drop the float bowl and have a look to see if there is any debris collected in there. If there is, then a good cleaning may be in order. You can likely clean out the carburetor without using any parts. You should be able to drop the float bowl with the carburetor mounted, but you will have to remove the air filter assembly.
I d-loaded the Kohler service manual and am reading the schematics and tech stuff tonight. Correct me if I'm wrong, but doesn't cleaning the inside of a carb require taking the top section off 1st? I'm going by my Holly carb. days @ the race track.

Unlike my chain saw this twin Kohler is a bulldozer. The only thing that ever slowed down the engine was deep puddles of water in the swale while mowing the grass. This is a primo engine!:)
 

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The top part of this carburetor is the body. There is a plate on the very top, but I rarely ever remove those. The fuel flows into the float bowl first and is picked up by the main jet. This feeds the idle circuit, so if anything got in the carburetor from your fuel, it came from the float bowl area. This is also the easiest part to remove without taking the entire carburetor off, which is a little tricky.
 

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Discussion Starter · #8 · (Edited)
The top part of this carburetor is the body. There is a plate on the very top, but I rarely ever remove those. The fuel flows into the float bowl first and is picked up by the main jet. This feeds the idle circuit, so if anything got in the carburetor from your fuel, it came from the float bowl area. This is also the easiest part to remove without taking the entire carburetor off, which is a little tricky.
Hello, I worked on the tractor today. This carb has a solenoid attached to another part of the carb which goes into the bottom of the fuel bowl. I took those parts off and removed the bowl. There wasn't much inside the fuel bowl, but I cleaned all areas including the main jet with carburetor cleaner.

I did remove the top piece and noticed there was a small jet in there so I proceeded to spray the jet and the area. I then put everything back together and the engine cranked, but would not start. The battery started going down so I attached a battery charger to it. It finally started but stalled a couple of times. When I could keep it running I adjusted the low idle speed and the air mixture screw and the engine was smooth.

All seemed good so I drove around the yard with the cutting deck on. A few seconds later it stalled and would not start. I got it back in the garage and jump started the engine again. The tractor has an electric PTO and it did this to me a few months ago. It turned out the battery was no good.

I got the tractor running again and drove towards the shed. It died before I got there. I pushed it into the shed and hooked up the battery tender. The light was bright red which is bad, so tomorrow I'm bringing the battery to Pep Boys to have it checked. This happened exactly like this back in May and at that time the tractor needed a new battery.

The good news is after cleaning the carb and making adjustments it idled fine. I'll let you know how I make out with the battery tomorrow. I can't think of any other reason why the tractor would die like that. Like I said, it did this to me once before. I'll get back to you. Thanks for your help.:thumbsup:
 

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You may need to check the alternator output. The alternator should provide enough power to keep the engine running. It could also be a bad connection at the fuel solenoid or the ground wire to the carburetor. Did you make sure and reattach the ground wire, it should be attached to one of the screws on the top plate of the carburetor.
 

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Discussion Starter · #10 · (Edited)
You may need to check the alternator output. The alternator should provide enough power to keep the engine running. It could also be a bad connection at the fuel solenoid or the ground wire to the carburetor. Did you make sure and reattach the ground wire, it should be attached to one of the screws on the top plate of the carburetor.
To begin with I got a new battery yesterday and installed it. The engine started and ran until I attempted to adjust the idle mixture screw. Then it died. I was not able to start the tractor immediately. This morning it started and idled for about 10 minutes. I drove it out of the shed and it started surging badly after I put it in gear. I was able to drive it into the shed, but the engine died before I could attempt to readjust the idle mixture. What is even stranger is the engine does not start after it surges and stalls. The manual says to turn that screw clockwise until it seats slightly and then back off 2 1/4 turns to start the adjustment process.

I don't know how to check the alternator or where it is. The fuel solenoid has a wire coming out of it and it plugs into another end securely. The ground wire is attached fine and tight.

The original problem of not idling is gone. Perhaps I should have left the idle mixture screw alone as now driveability is gone. At this point in time I'm not sure what to do. I was thinking of taking the idle mixture screw out and looking to see if there's any debris in there. I ordered a gasket kit, but it does not have any screws or other parts.

At this point I look to you to possibly help me figure this out as it appears the idle mixture screw is causing the engine to surge and stall out. Prior to me touching it there was no driveability problem. The Kohler service manual states that screws should be replaced if there's a problem. Before this incident the idle mixture screw was never touched since the tractor was new 8 years ago and it always ran great.

Let me know your thoughts. Thanks, Walker:confused:
 

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The problem could be fuel delivery to the carburetor. Can you tell if the fuel is flowing through the fuel filter alright?
 

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Discussion Starter · #12 ·
The problem could be fuel delivery to the carburetor. Can you tell if the fuel is flowing through the fuel filter alright?
I blew through the filter and didn't feel any obstructions in it. What else can cause an engine to surge? Solenoid? mixture screw? What else is there?
 

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Have you checked the fuel pump delivery? It may have not be pumping fuel to the carburetor consistently.
 

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Discussion Starter · #14 ·
Have you checked the fuel pump delivery? It may have not be pumping fuel to the carburetor consistently.
I got a new fuel filter @ Sears & installed it along with new plugs. I cranked the eng. & noticed the new filter- (See through) wasn't filling with gas so I shut it down and sucked on the tank hose. That filled the filter and fuel line to the fuel pump.

I then took out the idle/mix. screw and cleaned it off with a clean soft rag. There appeared to be a minimal amt. of blk. ring around where the screw had been seated since new and I wiped it clean. Turned screw in all the way, backed off 2 1/4 turns and the eng. started with no problem.

I let the eng. run for about 10 mins. @ about 1200 RPMs and turned the idle/mix. screw a little @ a time in both directions until I got the eng. pretty smooth. Unlike yesterday- the eng. didn't sputter & die when I turned the screw.

It was raining so I engaged the PTO in the shed @ full throttle. It seemed smooth. Tomorrow I will try it in gear and see if the eng. surges in gear with blades off. That's when it died yesterday outside.

Question: Should the fuel pump have sucked gas from the tank & filled the new fuel filter? I did it and it kept running. I thought the pump would pull the gas from the tank w/out my help.

What do you think now?
 

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Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.
 

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Discussion Starter · #17 ·
Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.
Tomorrow I'll get the tractor out if it doesn't rain again. I have the hood off as it was hard to get to the carb. If it runs fine in gear @ high throttle I think the problem will be resolved. In the shed it runs fine @ full throttle with the blades engaged.
 

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Discussion Starter · #19 · (Edited)
Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.
OK, I started the eng., no problem. Backed it out of the shed for 5' - it started sputtering/surging & I got it back in the shed just in time.

Took off the fuel line to carb- NO gas. Took off line from tank- NO gas. I sucked back & forth into the pump and heard/felt a diaphram moving. You say there are check valves in the pump?

I don't think my tractor has venting from the tank. I took off the gas cap and no change. I guess it has to be the fuel pump.

Do you both agree?
 

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Discussion Starter · #20 ·
Generally the fuel pump should draw the fuel through the pump without any help. It may be that one of the check valves in the pump was not working good and since it is now wet with fuel it's working alright. Go ahead and give it a test run and see if it works alright for you. If not, like Justin I would also suspect a fuel pump problem.
Where to start. Took gas tank off and air blew it out. Had fuel pump & solenoid checked and they are OK. There was debris in the tank that caused partial fuel blockage causing surge/stalling under heavy load.

I thought I had it fixed yesterday. Tractor ran fine for 2 hrs. mowing the lawn. Great.

Today I started tractor, backed it out & 10' later it surged & stalled out. Gas IS getting to carb, so Monday I'm bringing carb to local Kohler repair shop. He blew out the tank and says the debris is somewhere in the carb. He will take it apart & dump it in chemicals to clean whole carb. It will cost $35 or so.

At least nothing expensive broke. Price for solenoid is a whopping $88.00. Fuel pump is $32.00.

I guess by Tuesday all will be back to normal. Thanks for your input. :thumbsup:
 
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