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1971 MerCruiser won't stay running

daveb's Avatar

Join Date: Jun 2006
Posts: 1

06-05-06, 10:46 AM   #1  
1971 MerCruiser won't stay running

I have a 1971 MerCruiser 140 4cyl that won't stay running below about 2000 RPM. It mostly runs fine above that, but occasionally I'll have to manually limit the airflow into the carburator to keep it running. But as soon as I bring the throttle back to idle, the engine dies unless, again, I manually adjust the airflow. Not sure if it's a carburetor problem or not, or even what to do to troubleshoot the problem. Any ideas?

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harveje's Avatar

Join Date: Jan 2006
Posts: 122

06-05-06, 05:14 PM   #2  
Sounds fuel related, Spark usually causes popping. Check / replace all filters and or water seperator, if nothing throw a rebuild kit at it. Is it a Roch. or mercarb?

Pwrbait's Avatar
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06-08-06, 07:55 PM   #3  
Are you limiting the airflow or increasing it? Is there any black smoke when you do this, or an acrid odor, does it run rough or smooth during this operation? Does it idle after you start it? If it does, and this problem only occurs after you've been running, then come back to idle, your fly weights in the distrubter may be sticking. Lots of variable here, start with the simple things first, and eliminate the things you know are good...good spark, clean filters, correct timing, good points and conderser (unless you've upgraded to electronic), ect, and make sure you have a manual for this engine so you can insure correct specs and parameters. Let us know what you find.

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