Honda GX390 in the winter, not good

[tjkubota93]

I have a gx390 on a small stump grinder. It has beenmost problematic small engine I have had. I hadrun the normal 10% ethanol with marine stabil in all my small engine stuff for years with no problem. After loaning my grinder to a buddy, it came back running better than ever. He put non ethanol gas in it. So now I buy non ethanol gas.

 

[leonz]

if you put larger fuel jets in it it will run even better and stink less.

 

[tjkubota93]

if you put larger fuel jets in it it will run even better and stink less.

Yeah I figured it was lean, the way it ran better with regular gas

 

[Ford850]

I looked up the parts diagrams for Honda Blowers and noticed the recoil shroud is fully enclosed compared to the wide open vented coved on most GX engines. That would allow the engine to get up to proper temperature in cold temps and maybe help warm and melt off the linkages and governor. Ottawa - maybe you can test that with a piece of cardboard covering the vents.

 

[CalG]

I looked up the parts diagrams for Honda Blowers and noticed the recoil shroud is fully enclosed compared to the wide open vented coved on most GX engines. That would allow the engine to get up to proper temperature in cold temps and maybe help warm and melt off the linkages and governor. Ottawa - maybe you can test that with a piece of cardboard covering the vents.

Don't miss the details!

Carburettor icing occurs INSIDE the carb bore. The Choke bore, the throttle plate. Call it what you want. When the fuel is atomized in preparation to be drawn into the cylinder through the valves, the vaporizing fuel COOLS the incoming charge significantly. If the air humidity is high, or if there is swirling snow crystals passing by the carb throat, that moisture WILL FREEZE on the inside surfaces of the carb. And that can happen quickly. One minute the engine will be running strong, and a short while in use and the thing will be blubbering and sputtering and die. Let it sit a few minutes, and the engine heat melts out the ice from the clogged carb throat, and you are all set to repeat the cycle.

Carb heat is a standard control in piston driven aircraft ;-)
The "heat riser" in older engines were put there to warm the carbs of older trucks and cars etc.

Those small engines often get put into positions where the environment is just not suited to the shrouding and air flow.

All I'm saying is the issue isn't with the external linkages. The issue is that the carb is not keeping it's self warm enough to ward off carb icing.

FIX THAT!

 

[Ford850]

I’m comparing the same model engine that’s used on BCS tractors and Honda blowers. Since they work well on the Honda blowers there are differences for ‘cold only’ use compared to the BCS engines. Other than the more closed shroud, the dedicated blowers use different main jets and no air filters. Iced air filters (as Ottawarob suspected) would cause most of these same symptoms. Rough running and then fouled plug.

 

[LittleBill21]

no snowblower should have air filter, none of the units i own ever had one including the new to me gx390 in my my HSS. it runs fine, although i did rejet it due to some comments on the snowblower forum. i run cheap 87 ethanol as usual with 0 issue

 

[Ford850]

I’m comparing the same model engine that’s used on BCS tractors and Honda blowers. Since they work well on the Honda blowers there are differences for ‘cold only’ use compared to the BCS engines. Other than the more closed shroud, the dedicated blowers use different main jets and no air filters. Iced air filters (as Ottawarob suspected) would cause most of these same symptoms. Rough running and then fouled plug.

I also found that along with using no air filters, they use a different air box design and some shielding to protect the carb and governor on the Honda blowers. Definitely several differences that makes the GX390 perform better on the Honda blowers compared to other equipment using the general GX390 engines in cold weather and snow.

 

[Trillium Farm]

Yeah, these are all summer activities. My gripe is primarily with it in the winter.

Are you using a Fuel conditioner or fuel antifreeze?

 

[BillyDBrown]

I'm working through my 2nd winter in MInnesota with a BCS 749 with Honda GX390 with this winter being harder than last. Sub zero temps have been common. Am also am having some problems. Control cables/lubricant?, Governor, Starting. I'll also look into that cold weather kit. Thanks for that info!