The title says it, It starts and runs and warms up good. Going through the gears 1,2&3 is fine even into the boost, in 4th and 5th gear she start running crappy around 5G. Took off the filter cover, all four slides move free in and out. they are clean. I started it with the cover off and noticed slide 4 was not responding at all. check for dirt and pin holes in the diaphram, nothing. I sure appreciate any input. Thanks Wayne 05/08/24
slide not moving
- Thread starter wayne billings
- Start date
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Sounds like that cylinder is not firing.
I assume you had the slide out for #4? I've had more-than one CV carburetor that when I disassembled a rack, I found the CV diaphragm edge not in the recess as it's supposed to be. It's folded-over somewhere around the perimeter. Another thing to look for in the slide, is that the needle is fastened in place as it's supposed to be, with the little tit indexing into its hole.
On the other end, inside the float bowl, the brass cap isn't holding the emulsion tube in-place. SOmetimes it's loose, sometimes the cap is just lying in the bottom of the float bowl.
As to what Sean said, spray some water onto the exhaust header as close as you can to the cyl head, and see how quickly it evaporates. Once the engine is hot, a spritz should evaporate immediately, and not run in drops down the exhaust header. Of course, an infrared laser thermometer w/digital readout gives you an actual temperature to compare one cyl to another, and among all 4. Harbor Freight has 'em very inexpensively.
https://www.harborfreight.com/121-infrared-laser-thermometer-63985.html
On the other end, inside the float bowl, the brass cap isn't holding the emulsion tube in-place. SOmetimes it's loose, sometimes the cap is just lying in the bottom of the float bowl.
As to what Sean said, spray some water onto the exhaust header as close as you can to the cyl head, and see how quickly it evaporates. Once the engine is hot, a spritz should evaporate immediately, and not run in drops down the exhaust header. Of course, an infrared laser thermometer w/digital readout gives you an actual temperature to compare one cyl to another, and among all 4. Harbor Freight has 'em very inexpensively.
https://www.harborfreight.com/121-infrared-laser-thermometer-63985.html
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Thanks Sean and Mr. Medic. I will check the diaphrams and ex. temp. cheers
MaxMidnight
Well-Known Member
Wouldn't the slide still move even if the cylinder wasn't firing?
midnight-- I would think so, in fact it does.
Hey! It's working. I pulled all 4 slides cleaned and checked the slides and needles as well, blew out jets and passage ways. I found that by pushing the diaphragms down toward the needle they smoothed out and fit better for the install. Then smeared a small amount of Vaseline in the grooves to help hold the diaphragms while installing them. that worked very well for me. don't use too much or it will squeeze out and may get on the slide. After a test ride it runs well. Thanks again for the inspiration.
Very good! Glad you reported back on your success. I find water soluble gel is good in the role that you gave Vaseline. It also works well in the role of holding gaskets during reassembly.
