Here's a red & white Honda engine (4 hp) problem that if somebody can solve for me I'd be very grateful. It runs a 12 volt alternator to charge a battery bank in the winter time. It is outside but well-protected from the elements.
Normally it runs great.
BUT: When the temperature drops below freezing, it often will ROAR when it starts up as if the throttle were wide open. However, the throttle is at its normal medium run position and nowhere near that roaring max and a setting where in milder temps it starts up perfectly.
The funny part is that I don't touch the throttle at all. The only controls I touch are the choke and ignition switch and it wasn't roaring when I shut it off.
The only variable is the ambient temperature.
When it roars like that I stand there and choke it some to slow it down for a couple minutes then shut it off and wait. Then after a while something must thaw out from the heat and it starts up normally. I have tried applying an external heat source to the engine but that didn't work.
I've tried running it out of gas and idling it way down before shutting it off by turning up the alternator load, but the thing still ROARS on take off. Like I said, this only happens during below freezing weather. And if my memory is correct (it often isn't), the colder it gets the more predictable this problem becomes.
Hmmm. Sitting here typing, I'm not sure if I ever tried closing the throttle before shutting it off. Don't recall. That would be something to try too. I don't normally shut down the throttle because I don't want to lose my medium throttle setting and because of it possibly being frozen by low temps. Yes, I think that is why I don't move it. Too cold and it will stick.
I'm hope somebody here can explain this problem so even I understand it....
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