MS460 Idle Problem Fix

Marcus Allan

New member
Joined
Sep 23, 2025
Messages
2
Hi all

Just need to write this up so it doesnt get lost.

I own an old but awesome MS460 that has been experiencing idling issues - constant rough idle plus stalling at idle when hot. Our local repairer have been treating it as a fuel delivery problem and did not perform a pressure test to investigate any other issues. After the third visit to fix this persistent problem, they did a pressure test and the problem turned out to be a failed "Valve Jet". Have added the assembly diagram for the HS14 carbie - the valve jet is part number 7.

Hopefully this is useful info for someone.
ms460-0011.webp
 
Hi all

Just need to write this up so it doesnt get lost.

I own an old but awesome MS460 that has been experiencing idling issues - constant rough idle plus stalling at idle when hot. Our local repairer have been treating it as a fuel delivery problem and did not perform a pressure test to investigate any other issues. After the third visit to fix this persistent problem, they did a pressure test and the problem turned out to be a failed "Valve Jet". Have added the assembly diagram for the HS14 carbie - the valve jet is part number 7.

Hopefully this is useful info for someone.View attachment 168
Marcus Allan, thanks for flagging the valve jet issue and sharing the diagram. The part is often overlooked during rebuilds and it’s good to see someone trace a hot idle stall back to it.
 
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