harbor freight engine 420cc

[rogerf]

I agree it's often the choke, and it's worth checking that the choke fully closes, but I'd be warming the carby up with some warm air just to be sure it was carby related before messing with the choke butterfly.

I've had more than one ignition module that wouldn't work much below freezing and replacing the models solved the problem.

Really depends how much time you want to invest in problem.

Cheers & good luck.

[ParkinLube]

Seeing as you have had 2 of these that do the same thing would lead me to think it is in the engineering of the unit itself. More specifically, the carburetor probably isn't designed to atomize the fuel mixture at such a cold temperature.

[rogerf]

Maybe a question to Harbor Freight asking what the temperature specification of the engine would be a worthwhile execise

I've no idea what they will tell you! However China does have a wide range of winter temperatures. In their north east it can get as low as -40 (strangely the same in Fahrenheit and Centigrade). Around Beijing winter temperatures are usually warmer at not much below freezing. This makes me think that there must be Chinese carburetors available which will work under your winter temperatures if only to meet their own domestic needs.

Since you've had two engines which won't start in your winter temperatures even though fresh fuel and a new plug has been used, I reckon it's fair to ask if they are designed to be used in winter or not. If not the seller should make it clear the engine is only for summer use.

Looking forward to finding out what the temperature specifications say

Cheers, Roger

[bgsengine]

This makes me think that there must be Chinese carburetors available which will work under your winter temperatures if only to meet their own domestic needs.

Probably is, and might work fine for Canucks and Aussies, but here in the states, we have Big Brother breathing down our necks with the EPA , CARB and the like - even if we could buy one of those china built carburetors, installing it exposes us to a potential fine of up to $37,500 USD ... if we could afford to pay that fine, we could afford a couple dozen OE Honda Engines.

But yeah - it probably IS carburetor related - EPA compliant carbs , especially the Clones from China are notoriously lean.. so it is a *very* fine line between performance and emissions output - the cheap way to solve emissions output is to solve what is being *input* , thus a lean carburetor. perhaps choke may be modified, perhaps a jet may be oversized .001 or .002 or so - but the end result is, it needs to be made a little richer, but yet still somehow remain within EPA compliance - which, without certified testing facilities to sign off on the engine's actual performance and emissions, would be impossible.

On the bright side, I challenge anyone to actually find me an actual event where EPA enforced compliance on those laws against an individual (I can find plenty where they do so against businesses, up to and including the seizure of as much as a couple million dollars worth of engines or machines, in addition to the fines - most recent one was a company importing non-compliant Youth ATV's EPA got themselves a couple container loads full... )

[KE4AVB]

What we actually need is cleaner burning fuels that don't harm the engines. With it comes the fuel the Chinese gasoline is most likely very different blend then what we have here in the USA. Currently if I remember correctly we have at least two different temperature sensitive blends here not counting the different octane versions; a winter blend and a summer blend. Here in my neck of the woods they some time change between the blends too soon and cause headaches for a lot of us. Other areas probably have their own regional blends too.

Now I know small engines are not the same as the bigger versions but I still think that the engineers can do better job of finding a balance where things work better and still give us the improved emissions that government wants without giving us techs such headaches.

There are several other things that can modified that will affect the amount of fuel burned without going so extreme at carburetor end. Back in the late 1980's I took 1979 Malibu Classic with a small block V8 that was getting only 16 miles to gallon avg and ended up with it getting just over 22 mpg avg. The only things I changed was the addition of variable duration lifters, a mild racing cam, and installed a turbo muffler; no mods to the carburetor. I gain another 3.5 mpg later when I change to a 350C transmission. Kinda wished I had put in the 200R4 metric transmission; it had the same gear ratios as 350C in the first three speeds expect it had .7 to 1 overdrive too if I remember correctly on that ratio.

[bgsengine]

Problem: MPG is not the same thing as Emissions.

Fuel economy has nothing to do with Emissions controls, which the EPA compliance is all about. They could care less how much fuel economy the engine gets provided that the total emissions output falls within their standards.

They could probably certify a richer running engine by adding things like catalyst mufflers, bigger flywheel fan, bigger cooling fins, re-engineered combustion chamber, evaporative emissions controls, and the like - but then the cost of building the engine would be much more, so the selling price point would increase exponentially.

Making an engine leaner is the *cheaper* solution to EPA Emissions compliance, not necessarily the best one.

[KE4AVB]

Either way I still created less emissions overall by burning less fuel in the same time frame. I wondering how they justify the extra nitrous oxide that the lean burning small produces; although, I have heard of some using cats now.

When things are just based on the engine performance alone I can see where they get their ideas. When you add in the powertrain then the same engine can have overall different total amount emissions during a specified time period depending which is used. I got the same Kohler 17hp engine on two mowers one hydrostatic drive and the other is a manual drive; both 42" cut. The one with the hydrostatic burns 50% more fuel to cut my yard than the manual version. This makes that mower 50% more polluting I my opinion. I know grass height and weather changes but these were tested over a two year period here.

It is why I am selling hydrostatic one and keeping the other one, besides I can pull heavier loads uphill with the manual one.

And with this I will end my input.

[rogerf]

I have always wondered about the somewhat narrow interpretation of pollution apparently used by the EPA.

Is a short term enrichment to start an engine going to create more pollution than continued cranking and failure to start?

Admittedly it was years ago, but I remember being bemused by "modifications to improve pollution" which basically bolted an air compressor onto an otherwise unchanged vehicle engine. The compressor blew air into the exhaust stream and the result was that the percentage of 'noxious gases' present in the exhaust gas was reduced by about a third. Of course the total noxious gases was increased because the engine had to burn more fuel to drive that air compressor. But the combined engine compressor package was deemed to meet the regulations, and the engine on its own failed

Good luck getting some realism into that organization


Cheers, Roger

[finetune]

called hf, talked to a tec he said he had not had any trouble with cold starting engines. it must be me.

[chewy78]

you could maybe go up a jet size or two if it runs on the lean side. They should use some of the same honda carb parts like the main jet