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« Last post by Scaryfastatx on October 26, 2026, 10:21:15 am »
Truck is back on the road, made it to work today no sweat and some extended cruising over the weekend
what I did was first try to remove the orifice from the return line on one of the pumps that I had, but it wouldnt budge
so I ended up getting an .060" orifice from a carb and machined/turned it down so it fit inside the return hose barb on one side, and the other fit snugly inside the hose
So far so good
its starting up much quicker, and doesnt need what I thought was a warm up with the older pumps.
I think these pumps are getting past QA/QC at the factory without any sort of flow testing or orifice
so with the 3/8 line feeding the pump, and a 1/4" full flow return, and a 3/8" line going up to the carb and through the filter and check valve, the return is seeing the majority of the fuel so the carbs bowl runs low
I think this can also cause some cavitation inside the pump which will run hotter and potentially cause some erosion/damage on the soft goods inside the pump, with the already lower quality materials we have now the pumps are dying quicker
so in theory with the orifice in-line it will only bleed off a tiny bit of flow since its the higher resistance line compared to the line going up to the carb
basically 3/8" in, 3/8" + .060" out should keep the bowl in the pump more full and reduce bubbles/vapor accumulation
Fingers crossed!
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