Thank you! I will give it a try.
Larry

1976 JD 400 Walbro question I have partially restored JD 400, cleaned fuel tank, new lines, new fuel line filter, new antibackflow fuel pickup in tank, rebuilt at least replaced gaskets, pump diaphram in carb. It starts, it runs, then dies out after 10 seconds or so. Here is the first question: On t...

I used the same ones that were in the axle plus a little blue threadlock.

Problem solved. I ordered a used part from a fellow JDsledder...

I have a 1976 JD 400. Finally I got it started and engine revved up when suddenly one of the drive cogs snapped. I may need more than one but one for sure. I haven't looked too closely. The part number is AM 52563. It looked like you had some in one of your pictures. I may be needing the entire axle...

The Good and the Bad..... I jacked the track off the ground and set the carb. Slow speed out 1/2 turn, high speed 1 1/4. Set the choke...pulled it a couple times and it jumped to life....revved it a bit...opened the choke and BAM the left drive sprocket broke...anyone have a line on a AM 52563 or kn...

I already replaced the crank seals and now its starting after switching the wires from the CDI to the coils. Original electrical schematic had the white wire going to coil for cylinder 1 and red to 2. That's how I had it connected. We switched them putting red to #1 cylinder and white to #2 cylinder...

I apologize on the front end here, you've been advised by the best here and I didn't read the entire thread BUT double check the cdi wires are hooked to the correct coil or the spark plug wires aren't crossed many aftermarket cdis have the red and white wires crossed also it is easy to mix up spark...

Update. I took it to an 'expert" small engine mechanic who assured me he could find out the problem. It's been there since the weekend. Today I get a text message from him. "Did you have good fuel pressure? I'm thinking Carb or timing is a problem. Compression is at minimum175 to 120 I che...

Thanks lwb140. I'll check into that!
I took the Walbro apart and cleaned it yesterday. I didn't put it on though. I decided to try to see if it would kick on just ether. No luck. Then I thought that perhaps the impulse tube being open might have affected it.
I will follow up on your advice. Thanks!

Update: This weekend I took the engine out, cleaned it removed the pull starter assembly, fan pulley and flywheel. Replaced that shaft seal and reassembled. Then removed the clutch, shaft seal cover and then replaced that shaft seal and reassembled. I removed the intake manifold and checked the reed...

Thanks Troy and Harley. The airbox is off. I have had that problem with critters using the airbox or the exhaust for nests. The blowing out of the seals makes a lot of sense. It was loud and toward the lower area. I any event, taking the engine out is not a big task and I still have my 440 Cyclone w...

Do you know when the last time the crank seals were replaced? Worn seals cause the same symptoms. No I don't know when they were replaced. Sounds like I will have to pull the engine. I was hoping there were other things to rule out. So you don't think the backfire could have affected the timing or ...

Here is some general info of your '76 400. Check your serial number to see if it falls within Serial # Range: 55,001 - 70,000. The KEC 340/22 is reed valve engine. I would say you have carberator problems now since you have spark. Model Year: 1976 TYPE CODE- J400E Serial # Range: 55,001 - 70,000 Ma...

1976 JD 400 340 CCW Have spark, good compression won't start with starting fluid. Details: I obtained this sled last year. It was in great shape physically and seemed to have good compression, great track and everything appeared intact. When I got it home I checked the compression 120 both cylinders...