78 express won't run

I am having trouble with a 78 express the moped is in real good shape but I can't make it right. When I brought the bike home it would start by spraying fuel in the carb and I started there by cleaning the carb. It ran and I drove it up and down the street to set the mixture I was close and it died wouldn't restart. I cleaned the carb again and it started but smoked and blew oil I thought I had killed it but had a guy with more experience tell me I still had carb problems and it wouldn't lean out it was too rich. I cleaned some more, and got the same result. I switched carbs and the same smokinging mess. I then swapped engines, and the one that's in it now will start on the first try but dies shortly after. there is some mystery fluid that runs out of the exhaust and from my auto experience looks like oil and water mixed sludge. It leaves the same nasty sludge on the plug. It won't restart unless I let it sit for an extended period and then does the same thing. I haven't checked the compression on the one that's in it now but had 90 psi in the original smoker. If there is a remedy for either please let me know before I try to find a new piston and rings.

Re: 78 express won't run

Did you replace the old fuel in there? If that bike has sat very long it needs the gas and injection oil replaced. Also,use only a new spark plug after you flush new fuel thru by loosening the drain screw on the float bowl.

Probably the gas is just contaminated , but also check and clean the points and regap to .016".

Muffler and exhaust port may need decarbonizing too. that bike also has reed valves. don-ohio (:^)

Re: 78 express won't run

John Massie /

The tank has been cleaned and lined the oil pump has been removed and primed, the oil is new I keep switching plugs because it contaminates it shortly after starting and like I said the sludge drips out of the exhaust. Is there any fluid to lubricate the bottom end from the piston down into the crank case that may have been contaminated?

Re: 78 express won't run

Leon Swarmer /

A quick answer ..NO.

The lubricant for the bottom end is the gas/fuel mix that goes from there up into the cylinder for compression and firing.

There is no water on this ped at all.

Leon

Re: 78 express won't run

Leon Swarmer /

what color spark do you get if you pull the plug and ground it to the cylinder., and spin the engine?

L

Re: 78 express won't run

John Massie /

The spark is blue. It finally ran last night after several attempts at starting. it idled about two minutes and then the RPM's ran way high and it died and wouldn't re-fire. I'll try again tonight. I'm thinking there is some kind of fluid in it that shouldn't be maybe from sitting in the weather. Hopefully I can get it all to clear and my problem will be solved. Although I can imagine it turn over at all with water sitting in it for very long.

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