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43lx run on problems

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blaine_barnett

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"I've got a '94 4.3lx

"I've got a '94 4.3lx mercruiser that like to run on after I kill the ignition. It usually does this only after it's warmed up and then it really gets bad at the end of a day on the water. I've tuned it up...plugs, timing, idle, and carb mixture adjustment and I still have the problem. Any suggestions would be great.

thanks
Blaine"
 
Decarbon the valves and piston

Decarbon the valves and pistons w/Mercs. product is one possible answer. Another is to be sure the throttle closes when shut off. Let the engine cool at idle for 5 mins. before shutdown. Run several tanks of Chevron higher octane fuel w/Techron in the boat to keep the carbon down. You can buy Techron combustion chamber cleaner to put in the fuel; about $8.
 
what temp is it running at now

what temp is it running at now?
cooler thermostat might help
too hot a plug
too lean fuel mix
too much carbon on the pistons
 
Thanks for the advice. I'l

Thanks for the advice. I'll run some good gas and products thur it to see if this helps. The temp usually runs about 175 F ...

thanks
 
"Follow the recommendations in

"Follow the recommendations in the attached MerCruiser Service Bulletin #97-17 Engine Engine ‘Dieseling’ or ‘Running-On’. It helped me.

<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_pdf.gif""" align=left alt=""application/pdf"">MerCruiser Service Bulletin #97-17 Engine Engine Dieseling or Running-On
[url=""][b]MCSB 97_17 Engine Dieseling.pdf[/b][/url] (17.1 k)</td></tr></table></center>"
 
"Are you kidding me??? Merc ha

"Are you kidding me??? Merc has a service bulitin for dieseling??

I would have thought that these types of issues would have been eliminated back in the seventies???

OH MY GOODNESS!! how things come around again and again. I guess with the EFI generation getting into the repair field much has been forgotten about CARBS, timing, etc."
 
another thing to consider is e

another thing to consider is engine compartment
temp. Are you getting good ventalation with blower or vents? Is your idle speed correct?
A fast idle will certainly help run on.

Kurt
 
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