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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)
Shipping: All orders are shipped UPS Ground, UPS Surepost or USPS Priority when ordering online. Shipping charges are calculated based on weight, size, and quantity of boxes in addition to processing and handling including insurance. All shipping charges are the customer's responsibility (even if charges online are not the same as emailed or phone orders).
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.
Express/2nd Day/Next Day Shipments: Express orders must be made by phone orders only! Orders placed after 12:00 p.m. CST. will be processed the Next Business Day. UPS will only guarantee next day shipment. If you choose 2nd-day shipments expecting it before the weekend, UPS does not guarantee its arrival
Additional Fees: Double Check that the address you gave is correct. You may be charged additional fees to redirect your package to the correct address.
PO Boxes: We can ship to PO Boxes using USPS. However, UPS will only accept shipments to a valid street address. They do not deliver to P.O. Boxes.
International Shipping: International buyers are responsible for paying duties, taxes, and applicable customs brokerage fees separate from the merchandise cost. Buyers will generally pay these fees upon receipt of your shipment. Buyers may be charged additional fees once they receive the package. Read our international policy here.
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UPS Estimated Shipping Lead Times
USPS Estimated Shipping Lead Times
