Terrilee.. That is the first time I have heard of a plug causing backfire but I believe you. I like NGK plugs too but I really suspect it was not the brand but perhaps a defective plug or not tight or something. Strange but engines are always doing somnething a little strange.
I would start by replacing all the fuel lines that show any signs of leaking with good old ameriacan fuel lines. Some of the chinese fuel lines are not ethanl resistant and will soften and disentegrate with our fuel. But I suspect you may have a line disconnected. You could have a float valve stcking open in the carburator. Check about a bit with other scoot riders and find yourself a mechanic or take a class or two at the local JC or hight school Learning to be a mechanic by yourself is sort of assuming being a mechanic is a no brainer. I t really is not. their are some pretty good books that expain how the fuel system of a scoot works. Even out library heare has a lot of stuff. Good luck lefty2
I am always expect any late (after 1968 or so) carburated engine made to be sold in the USA to have a stock set up to run too lean for my tastes. It is set up that way to meet the emissions requirements. The problem is that lean runs hot. High throttle, a little lean and the temperature of the engin rapidly goes up making it run leaner yet. Notice true high performance engines. They blow a lttle black smoke (rich) rich is cooler. Engines love it. I'd rather need to clean the plug now and then. Particularly on an Air cooled engine.
It has to be very very rich to reduce full throttle performance - as long as the plug does not fowl.
Listen to Terrilee. She is 100%. I am not saying there are not other great people in business, I am jsut saying Greg has earned my admiration too. In fact, I sort of use him as my business model as a dealer for Legacy Lifts. Cheers lefty2
Naybe we ned to help our friend out. I for one ride in Florida. I will never see his shop. but he does not know it. So perhaps I should go on face book and ask him some questions just toget the ball rolling. In the same way, perhaps super dave needs to get some help from locals whoare riding other scoots to start asking questions and perhaps even pretend to have heard from this guy riding something or other. Any thing to keep super dave out of the spotlight. I learned long ago that sometimes the best approach to a SOB is to be sneaky as hell. In the meantime, start asking around. Perhaps even learn to be your ouwn mechanic. We typically are pretty good at bringing a newbee up to speed. Some of these scoots should not be sold but most can be domesticated. Cheers
There are a lot of things that can cause excessive blow buy. I for one am not a big fan of hard break-ins. I like a little babying for a few miles.It is easy to scuff a piston skirt. The stock emission system pumps the blow by and some exhaust gasses back into an engine that is not as well cooled as I think it should be. top all that off with a carb system that tends to run on the lean side means it is really easy to overheat these engines often built with darn near pot metal.
I am a bit embarrassed how long it took me to realize that the 150cc version of this engine built to the cheapest standards is probable a bit bigger than can be cooled properly.
So what to do. 1. be careful to change oil at the first sign of color change. Any sign of tan or brown. 2. read the plug frequently. I want to see signs it is a little rich. 3. If it bogs down, let it. slow down and let it cool a little. 4. consider getting a high end Taiwanese head, cylinder,piston and rings instead of the cheapest EBay Chinese stuff.
Did I miss something? JR is right about the need to burp this scoot. Getting all the air out of the engine is critical. Any air is likely to remain and create a hot spot that Will generate steam and stop the circulation of water. Since this scoot has a bit of history of overheating (and fan not working) and since it idles and runs as low speed without overheating, I wonder if the problem is not a defective radiator or a water pump not really pumping well. I think I would remove the radiator and determine if some of the passages are not blocked. Also make sure air flow is not partly restricted. A compression check would not hurt just to try to ensure the engine does not have a problem. And read the plugs. a little lean fuel/air ratio increases the cooling load under part and full throttle a lot.
I suspect you really need a good cooling mechanic to work through the Long list of things that can cause overheating.
How does he know he flooded it? I doubt it? It is hard to flood these scoots. I would go with a plug wrench, and a compression gauge, a pair of jump cables and a decent battery ( your car will be fine, Just be sure not to have your motor running when you hook up) and do a compression test. If you got less than 100 psi it needs some work. A uses 150 running is worth 500 to 750. At best. Not running- guess? Not much.
You are a dreamer aren't you? A 150cc scoot with a chassis and suspension designed for 50 -55 at 70-75. hang on boy.
Put enough money in it and it might do it. For a minute or 2. That air- cooling system will not handle the heat for more than a few minutes. Seems that despite the mixture control all the way to WOT that EFI gives, all factory EFI's have water cooling. Even 50cc 2t's.