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The low speed controls the fuel that enters the low side fuel well. This low side adjustment screw is sometimes called an idle mixture screw but it does more than control the idle. The low side screw also controls the low speed, and midrange and can be viewed as the main circuit of the carburetor.
On 2-cycle engines, the original engines for the Tillotson carburetors, these carburetors do idle. On 4-cycle engines, the carburetors are too rich at idle, especially on methanol. This condition causes a dead spot or hesitation and leaning the low side will cause the engine to run flat and not accelerate. Both conditions are fixed by not setting the low side mixture or idle speed screw to idle the carburetor.
43-991 OE Tillotson HR Idle Mixture Screw (Positive stop type). Fits HR-181B, HR-184A, HR190A, HR-191C, HR-191G, HR-196A
Returns- Returns must be communicated by customers within 7 days of delivery and sent back within 30 days to receive a refund. No returns without authorization will be accepted. All returns must be accompanied by a copy of the receipt and a note. All items must be returned complete and in new condition.
All returns are subjected to 20% processing and restocking charge after the product has been inspected. The shipping cost will not be refunded.
Refunds will be made back to the same method of payment when ordering those parts. We will not refund a different method of payment.
Non-returnable Items Include- Close Outs and Clearance Items, Special Orders, Custom Orders, Used Parts, and Cut to Length Items. (Other items may apply)
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All standard shipping orders will be shipped within a day or two on weekdays. Orders placed on the weekend (Fri-Sun) will be shipped Monday or Tuesday or the first weekday after a holiday. Custom or Handbuilt Products may require more time to be built before shipping. For any reason, an order may be delayed or prevented you will be contacted through phone and/or email.
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UPS Estimated Shipping Lead Times
USPS Estimated Shipping Lead Times