9.9 4-stroke dies at idle

Does anyone have a troubleshooting checklist for a 9.9 HP 4-stroke Honda outboard engine from the early 80's that dies at idle?

Thanks a million!

It's almost always due to dirty carb.

I agree with chawk_man,

Here's how it goes:
If it will start and idle...even just a bit...that pretty much tells you the base engine is sound. Meaning; it has compression and correct timing.

Running at all indicates that the ignition system is firing and is "likely" ok.

So, that leaves us with the carburetor idle circuit being somewhat clogged...a VERY common issue with most HONDA.
Even more likely if you are NOT in the habit of RELIGIOUSLY completely draining (not just running out) the fuel from the carb using the drain screw.

If it were mine, I would pull the carb and give it a good cleaning. Many posts here on doing that although you should be at least a "tad" mechanically inclined since it is not simply a matter of "spraying some stuff" at it. But it ain't rocket science either or I couldn't do it!



Good luck and ask all the questions you want/need. Someone here will probably be available to help. I know hondadude has a trick or two he might share with you about the older carb getting "fixed" while still bolted up so give it a few days and see if he doesn't chime in.

Many folks end up doing the carburetor 2 or 3 times as it is hard to see / notice the tiny holes and passage ways.---They are usually missed the first time.--Do not give up.----Always drain the carburetor of fuel when done boating for a week or more.