clone engine carburetor

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clone engine carburetor

Post by Admin on Tue Aug 19, 2014 7:10 pm

Put good carb off my mower on friends mower. Tried and tried to clean her old carb to make it run right with no luck, and I am usually pretty good at rebuilding carbs. So looking on ebay found new replacement carb that looks identical for $9 shipped on slow boat from China. Except its for a horizontal shaft engine. So has fuel shut off built in and a low speed idle circuit. EPA made mower manufacturers lock engines to full governed speed all the time. Guess less pollution at higher rpms. So manufacturers cut costs by eliminating whole low speed circuit, these engines just wont run if you modify things so throttle plate is closed enough that engine should run under 2400rpm, let alone idle.

The nearly identical crippled carb for vertical lawn mower engine is around $25+. Go figure.

Anyway I bought $9 one. Put it on and started engine. Oops running too fast, though I can manually hold throttle nearly closed and get it to idle. Looked at it, looked at old one. Damn it, they have the linkage from governor connected to opposite side of throttle shaft. So governor is actually trying to open throttle when it would be trying to close it on original carb. And vice versa.

Just got through welding up an adapter so it can hook either way. Broke dang drill bit making small bolt hole through adapter so have to hunt up another bit before i can finish. My adapter has to bolt to the OEM plastic end on the throttle shaft of the carb. Then I have to drill another little hole in adapter for the linkage to hook onto it.

Will post pic when I am finished. The end on the choke plate shaft is also different, so probably have to drill some holes in a small washer to change linkage hookup on it too.

Devil is always in the details. If one is super patient and doesnt mind fiddly kind of tinkering, then can make nearly anything work, eventually....

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Re: clone engine carburetor

Post by Admin on Sat Aug 30, 2014 10:24 pm

Finally cool enough after front moved through for me to finish up with mower carburetor. My adapter works fine, mowed some with it. Governor kept engine running constant rpm. To adapt choke linkage, used stove bolt and a penny with three holes drilled in it. Had to replace both rod from governor to carb and choke linkage rod with ones homemade from wire salvaged from old clothes hanger.

Try to take some pics, wasnt thinking to do that when I was assembling it. Nothing earthshatteringly innovative, but maybe somebody might want to do this and at least know its possible even if they come up with somewhat different looking adapter. I mean the horizontal shaft engine carb has the low speed carb circuit, so one can idle down if one wants to. Useful especially if one wants to use mower engine on something else like tiller that requires slower engine speeds. You can use a cast iron flywheel from a horizontal shaft clone engine on the vertical shaft mower engine too, so it will run smoothly without a blade attached to it. You just need few washers as cast iron flywheel sets up bit taller than the aluminum flywheel. So rope pull assembly has to set up bit higher too. Thats all adapting required for that.

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