Hello I am just wondering if you can replace the soloniod on the carb with a manual needle valve like in the older briggs engines.

Hi,
No you cannot use an adjustable needle because of the EPA. There is a simple plug that it can be replaced with. Warning: this is an overhead valve engine and that solenoid has a purpose! If you do replace it, you MUST throttle the engine down for a few seconds before shutoff.
691657 is probably the part number, but you did not provide the engine numbers.
Peace,
Clarke