Engine Miss Over Bumps

[tractordude]

Originally Posted by darkminion_17

check the contacts on your ign. switch.They may be loose.

ditto, I just fixed a J.D. with this problem. Bad/burnt connections on the key switch

[donnelly.me]

Ok guys, i checked the wire from the points to the coil and I couldn't find any bare spots
. I changed the plug wire for kicks and that didn't help either. I checked the plug on the ignition switch and that was tight but I cleaned up the connections anyway. While I was driving over the spots itusually sputters I tried at half throttle full speed and it didn't miss a beat. I'm leaning towards the float spring mentioned earlier in the thread.

[teejk]

sounds like you've ruled out the easy stuff...I guess if CC has a spring part they must have had an issue...as far as I can figure, if everything else in the carb is ok (particularly the main jet), I guess the float bouncing could starve the fuel bowl at full load. but I'll shut-up and let the experts opine.

[Dave R]

Run it in the dark and watch for either a spark jump to ground, or a loose ground. It sounds like the ignition is grounding out when you hit a bump.

[zippy1]

Sounds very much like an electrical problem to me also.
Hope you get it tracked down.

[cadzag72]

I can see that there's been a lot of suggestions, but I'm going to throw in one that happened to me. make sure your condenser isn't mounted loosely; mine had loosened up a bit and bumps and vibrations made the engine skip and sputter. it drove me nuts trying to find the problem. once I snugged it up, problem vanished!

[teejk]

Part of that "grounding" thing I alluded to earlier. I had my 1250 in storage for a few years and couldn't get it to run. Did all the fuel cleaning etc. Then pulled the wiring diagram from here and started to trace all that stuff removing/cleaning/reconnecting all the grounds. Battery to frame was easy...on the 1250 there is another heavy ground wire from one of the starter bolts to the front of the frame. Rather than list all the components that need a good ground (there are a ton of them), pull the wiring diagram.

Where switches are involved, a squirt of WD40 followed by a little "time out" will suffice I think. But where the ground involves a mechanical connection (like the condenser), remove, clean, reconnect.

So the 1250 is running great (38 years old now). I think the problem was that the wire connected to the points was a bit loose (points on that machine are a major PITA) but I'll never really know since I cleaned all of the other major grounds at the same time.

[David a Calkins]

the spring keeps the float level ,so you won,t rin out of fuel

[donnelly.me]

I tried to install the spring I purchased from kohler under the float today. I installed it with the larger diameter side of the spring under the float and the smaller diameter of the spring sitting on the bowl. This made it run worse. The governor was hunting really bad. Do I also need to re adjust the carb now? Being an add on part, no directions were included. I went through every wire having to do with the ignition again and still cant find any loose connections or bare wires. Thanks, Mark

[red56turbo]

Reading through the whole topic, you've gotten a lot of great ideas to check. IMHO, it doesn't sound like a fuel problem. Hitting a bump shouldn't starve the motor of fuel. Not vapor locking cause it only happens on bumps. Has to be something electrical. And believe me, an electrical problem can be frustrating to find. Have you checked the condensor yet to make sure it's tight? Otherwise, take some time and look at all the wiring and check for loose or rusted connections. Also check the wiring in the wiring harness clips. Sometimes vibration over the years can wear through the wire and if it's still in the wire clip, you might not see it unless you pull it out of the clip. You can also pull off the point cover and check the wire in there to make sure nothings amiss. Good luck and stick with it. You'll find the problem eventually.