harbor freight engine 420cc

[creia]

Most of these HF engines will run fine, however, some are just a TURD out of the factory, and will not run correctly. That's the chances you take and part of the trade-off for that cheap price. Have you thought about taking it back for an exchange? (been there, done that!)
Michael

[bobodu]

He said this is the second engine.

[creia]

He said this is the second engine.

You are 100% correct- I missed that.
Michael

[HondaG100]

The old saying is true. You get what you pay for.

[creia]

The old saying is true. You get what you pay for.

I agree and generally true, HOWEVER...
"Most" of these engines run fine right out of the box and really and truly are a terrific VALUE FOR CERTAIN APPLICATIONS. (e.g., a HF 6.5 HP for only $ 99.00!?). Now, before you accuse me being a HF engine lover (only), we have had numerous Briggs, Tecumseh,Clinton (remember those?), and HONDA engines over the years (still do). Sure, the HF engines are not quality-built, but they have their place and are cost-effective alternative for limited/some applications.
Just my .02 cents
Michael

[bobodu]

Try to find a Tecumseh that doesn't hunt right out of the box.

[rogerf]

Hallo Folks,

I guess we'll just have to get use to these Chinese engines - whatever the brand name they are sold under. Selling price will have its way! Here in Oz there are many garden machines with Chinese made engines sold. Briggs and Stratton are fighting back with their range of OHV engines, but a lot of folk decide on price alone, simply buying a new one when it 'fails'. Having said that all petrol/gas engines have the same needs to operate:- compression, atomised/vapourised fuel, air, spark and timing.

This engine starts and runs fine at workshop temperatures, but not when very cold. So all requirements are met at workshop temperatures I believe this eliminates timing and compression as issues.

But it won't start when cold This was a common problem with some vehicles in the 60's. Often the problem was electrical in that the engine was just not spinning fast enough to start when cold or there wasn't enough voltage left to create a good spark AND turn the engine. A bigger battery and or heavier battery cables together with bright clean terminals solved that problem many times. Maybe try to start the engine with a larger and warm battery on jumper cables, cold batteries don't perform well. If it starts with a larger battery on jumper cables you have a possible solution.

I recall that one car I had just would not start in the European deep winter ( -20centigrade) with one brand of spark plug fitted. It's a long time ago now, but I think that NGK plugs worked well and Champion didn't - or maybe the other way round! I'd say it's worth changing the spark plug for another and checking to make sure that the gap is correct and that the edges of the central electrode are sharp and square. Rounded edges increase the voltage required for a spark to happen under compression, and the voltage available at cranking speed could be lower than at running speed due to the laws of magnetism.

You mention that the plug was quite wet with fuel after trying to start the engine. Clearly fuel is reaching the combustion chamber but it is not firing, and starting fluid causes backfiring if I understood correctly. If the plug is wet it won't fire, and continued cranking with the choke set will flood most engines. I would try warming the carburettor with a heat gun or hair dryer and trying to start with a known good dry sparking plug. If the engine starts with a warmed (not hot) carburettor it might be suggesting that the problem is fuel related and maybe the tank was filled with stale or bad fuel which won't vaporise when cold. In this case I would try a fresh supply of winter fuel.

If warming the carburettor doesn't help try checking for spark (with a known good plug) whilst cranking if you have an in-line spark tester. If no spark try warming the coil - could be a temperature related ignition module failure - they have been known to fail at both ends of the temperature range.

I hope that rather long-winded series of suggestions will help. These cold temperature starting issues can be very frustrating to get to the bottom of, but I've never come across one which couldn't be solved with persistence. My first reaction would be to put in a new sparking plug, if that didn't work then try changing the fuel. If both of those didn't work I'd start the systematic fault finding procedure.

Good luck!
Cheers, Roger.

[finetune]

I had new gas,removed plug spun over to clear cylinder, installed new plug, put jumper pack on battery, put in 5-w30 oil, would try to start but would not till it warmed up outside to about 25 deg. all the other engines I have will start at 0.

[KE4AVB]

One note here. These Chinese engines are being constantly changed. They may have simply changed the choke butterfly to a different design that allows more air to bypass it at start-up.

I recently had a similar problem with a Ruixing carburetor on a leaf blower. The new carburetor was flooding the engine at start-up. It won't even try to start to start unless it was fully choke but as soon as it hit it flooded. Since I still had the old carburetor I looked at the choke butterfly. I found that they had change it to one that nearly completely blocked off when compared to the old one. When I tried the old butterfly it won't start unless I hand choked it but the engine ran fine afterwards. With this in mind I started modifying the new butterfly and when I got to 2/3 of the opening of the butterfly opening of the old one everything started working like it should.

[bobodu]

KE may be onto something...take a look at that choke and see if it is closing or need a hole blocked off.