I just got a really nice looking excel 3 for a mere $40!
I put fresh gas in it and it started up and idled nice...then I drove it about 10' and stopped and then it started to smoke, and then it slowly died. I checked out stuff for a few minutes and then started it again...I had to give it some gas in order for it to start. I tried to drive it again but this time the smoke was worse and it didn't want to rev above 3k rpms.

Looked at the plugs and both are black. They have black fluid on them that you can wipe off.

The guy who sold it to me said he was driving it last winter and then it died and he saw that the plugs were fouled. He parked it and didn't touch it after that.

I know that running rich will foul plugs...but since the previous owner said it was running and then fouled the plugs that would lead me to think the problem is somewhere else.

Can the injection system on these break in some way that would cause them to dump far to much oil into the gas?

Also, where the carb mounted to the intake is not a solid mount. There is a rubber boot that is attached to the carb and it just kind of sits over the intake's opening. Ill try and take a pic, because it doesn't seem right to me. The rubber boot has holes were it looks like it should be bolted to the intake.

If it is a problem with the injection system, how hard is it to bypass it and just mix the gas?

Attached Thumbnails

 

anyone know if the oil injection on this sled lubes the crank?
I read that ones that do cannot by bypassed.

Usually, if the oil pump lubes the crank, there will be lines going from the oil pump to the crankcase ends. If you only have two hoses that go to the carbs, all the oiling is done as the fuel mixes with the intake air.

I only see 2 small lines leaving the oil pump...the lines go to nipples on the intake runners (after the carb)

So if I run one line between those 2 nipples (as a way to block them off) and then run the 2 lines from the oil pump back to the reservoir (rather than having to remove the pump and block it off) then that should be all that is needed to run pre-mixed gas right?

I just got done trying it on mixed gas.
I took both oil lines off the intake runners and ran one line between them to block them off.
Put mixed gas in the tank and it did the same thing as before. It starts right up and has no trouble idling...but after you give it some gas the amount of smoke increases and then it will bog if you try to move and it will no longer idle.

Is it possible for plugs to foul so bad that you have to replace them? Ive taken them out, wiped them off and put a lighter to them. I don't see how they could be causing the problem but I don't know what else could cause it.

When a sled sits for a while, the oil that is in the crankcase and on the bottom of the pistons and on the crankshaft settles to the bottom of the crankcase. When you first start the thread, the airflow picks up that oil and adds it to the oil you are giving, and you get a lot more oil than necessary. The plugs foul. That's more common on a sled that has been fogged.

Also, the sled is jetted for cold conditions. Running those jets in warm conditions makes the air/fuel mix really rich, which also contributes to plugs fouling. I've had sleds that could not move onto a trailer in the hot summer sun that ran perfect when it got cold, simply because of the jetting.

Both those conditions usually clear up when it gets cold and you run the engine up to operating temperature while riding. You could try smaller jets as a test, but when it gets cold, you will need to jet appropriately for the temperature to prevent overheating of the pistons because of the lean condition.

I don't suppose there is any way to get settled oil from the crankcase other than to run the motor?
It would be great if that was the issue but I wonder since the old owner said it fouled on him in the winter.
Also, temps here are in the 50's...not that far from the 30 degrees it is likely jetted for.

I would consider other problems over too much oil. A sled will run pretty well if it's got good spark and good compression, even if it's got a lot more oil than necessary.

Try pulling the spark plug wires and unscrewing the ends (most sleds use a removable plug boot.) Look into the opening where the wire threads; you will see a small screw-like contact. Is it clean and shiny? If not, replace the boot. NGK sells a couple of different ones, the one-piece boots are a little nicer. Before screwing the plug wire back into the boot, snip about 1/4" of wire off. That will insure that you have a good wire contact. That will rule out the wire as a problem. Going with fresh plugs will rule out the plugs, too.

What's the compression?

compression is about 110psi on both cylinders.

Compression sounds fine, you could try idling it until the engine gets to operating temperature; that may help get rid of any excess oil that's in the crankcase. Then swap in new plugs.

Check for spark if it dies, you could have a coil or stator issue that only shows up when the engine is warm.