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Old 09-01-2017, 09:05 AM   #1
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Default Merc 40 hp advice

New member here, looking for confirmation of my diagnosis of a stalling-upon-gear-engagement issue with my older 40 Merc.
Issue: engine consistently stalls when put into gear, need to shift from neutral to half throttle or more really fast (ie abusively) to prevent stall. Engine runs great at idle, under load, at partial throttle and at full throttle. Idle speed is OK
My diagnosis (have not had time to try adjustment): throttle cable does not move carb linkage fast enough to transition from idle/neutral to partial throttle/gear engagement, causing insufficient throttle for load leading to stall.


Questions: Can anyone confirm my diagnosis? Is there a means of adjustment at the engine-end of the throttle/gear controls? ... or is this symptomatic of worn linkages?


Tks for your input!


BTW,
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Old 09-02-2017, 08:55 AM   #2
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If your Merc 40 is a 2-stroke or a carbureted 4-stroke, I suspect the idle mixture screws are set too lean or partly plugged.
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Old 09-05-2017, 07:29 AM   #3
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Thanks for your reply...


Will check Idle mix screws, but since the motor idles fine, this does not seem to be the issue.


Any other thoughts from guys having experienced similar issues?
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Old 09-14-2017, 02:56 AM   #4
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Hello, mixture controls could still be wrong even though motor idles fine in neutral, there is no load in neutral, when you give it power, the idle jets have little or no effect as the other jets take over and the open venturi sucks air. Check the movement of the throttle linkage with the engine off and see how far the cable is pulling. Hope this helps.
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