honda 40 idle

[yamp]

Just wondered if any members might have some ideas my honda 40 nagging problem.Its idle is nice and smooth out of gear, but dead slow trolling in gear it coughs abit and sounds rough I have checked the mix screw and they are all set the same 3 1/2 out .I'm not to keen on pulling of the carbys and cleaning, the idle rpm is set to 800 to 900. I was thinking the syncing of the carbies could be out abit? should the mix screws be slightly different ? any advice or tips, trouble shooting ideas greatly appreciated thanks Yamp

[John Buoy]

The carbs clog up fairly easily in the Hondas
Need a clean and re synced by the sounds of it!!!
3 1/2 turns sounds a lot usually somewhere from 1 1/2-2..

Regards Frank

[dean grieve]

do yourself a favour find a dealer who has a vacuummate synchroniser most do, you will not believe the diff, they are essential for synchronising throttle values it will also check cylinder seals and valves which also affect correet synchronisation. if you have no luck send me a pm i may be able to help.

[Spaniard_King]

Which Dealer do you work for Dean??

[foxx510]

Try changing plugs too, our Honda 25 had a dodgy plug that caused rough low speed running before the plug fully gave up. The idle was a bit rough at times though, too, so a bit different to the symptoms you are seeing.

[yamp]

Thanks for replies fellas ,I will try and get the carbies synced somewhere the motor just had its 100hr service but they must not look at the syncronization to much,probably just oils and plugs etc so I not all that keen to take it back to the same mechanic if they didn t pick it up ,I mentioned it was running at bit rough at idle but he just said honda are not that smooth? and think they may have just upped the idle speed abit. I will let you know how things turn out or what I find out, thought about test running in a drum and tweaking the carby mix screws but might do more harm then good. cheers Yamp

[rooboy98]

G'day Yamp,

I have a 2000 model Honda 40HP and had a similiar sounding problem (rough idle) several years ago.

It was totally cured by doing what has been previously suggested above by other AF members.

I got the 3 carbies cleaned, tuned & synchronised with a vacuum gauge for $150......has run sweet ever since, even when I back the idle down slower than normal for a bit of a trolling session.

Hope ya get it sorted,

Cheers,
Roo.