High Idle sputtering with backfire then engine quits

[HoosierScooter]

My '87 Spree has 8,000 + miles. It was running with alot of carb adjustments in order to find the right setting for it to run right. Prior to that I did disassemble the carb, cleaned it up pretty good and re-assembled it. I cleaned the fuel tank via CLR with boiling water (worked great). Removed the petcock valve and soaked it in clean gas for 6-days. Re-installed the petcock valve w/o fuel strainer. Spree was running well except at high full throttle speeds. It would backfire and sputter and eventually die. Two days ago, I had the scooter running pretty good. Decided to help speed up the cleaning of the fuel system and bought some Sea Foam. Used the Sea Foam as directed for the alternative carb cleaning proceedure. Also put some Sea Foam in the fuel tank (about two to three caps full. Now the spree will at best start at full throttle during kick start and die. I understand that it will take numerous attempts to get the scooter to run with the Sea Foam. I am just looking for some guidance. Also, the petcock valve is stuck open. Are the petcock valves for other scooters O.K. as a replacement. If they are, the cost is about 1/6th the Honda price. HELP!

[Farfignugin]

your first problem (backfireing at full throttle) is a sure sign of running lean. I would also suggest running it WITH the fuel strainer. I guess as long as the replacement fits onto the tank it would work.

[islandbayy]

With the sea foam in the carb, keep feathering the throttle. Thing about sea foam, is it burns much much better once the engine is warm. So keep doing it, once it gets that right temp, it will stay running, a low idle, but will keep running. Once it's running, take it for a ride at full throttle until the white smoke from the exhaust is gone.

Sea Foam in the gas wont cause a harder start, but in the carb, it will until that seafoam is all flushed through/burned up.


Once the white smoke is gone, remove your spark plug, put 2 capfulls of seafoam in your engine directly, replace spark plug (best do to this when bike is warmed up). leave the seafoam sit in their for a good 5 minutes, then start your bike (will be a bit difficult, but not as much so as sea foam in the carb), and again, ride it full throttle.

This will de-carbonize the chamber very effectivly. You should get MUCH more smoke when riding with the seafoam in the chamber then with the carb, but it will not smoke as long.


You are now done ^_^


you should get a petcock, you can find manual ones for a few $$$, honda is a bit more expencive, but then again, you wouldnt have to manually shut it off every time you stop the bike. i'd recommend just fixing it the right way.

[HoosierScooter]

If my Spree is running lean, which setting do I adjust the jet needle to on the throttle valve? Is it at position 1 the top notch? The needle clip was at that position before I moved it down a notch when I first got the Spree. The adjustment seemed to make it run better then. Thanks!

[Farfignugin]

if the clip was at the end of the needle and you moved it down one notch, try one more, I think that is stock.

[Kenny_McCormic]

it depends if your needle is a 3 notch or a 5 notch if it has 3 notches it should be in the middle

[HoosierScooter]

The needle is a three notch and it is in the middle. It was at the top. Now the clip is in the middle.

[Kenny_McCormic]

is it running now?

[HoosierScooter]

The Spree is running intermittently. I've had the needle in all three positions. It seemed to work best in the top position (position #1). Although there is no backfiring now, the engine dies and then will re-start and die again shortly after. Possible problems could be my by-starter. The green wire is cut so I have disconnected it.

[berreta22]

When you posted earlier the strainer was left out..my guess is you sucked up some crap on the bottom of the tank. Clean the carb out really good again and put that strainer back in. You really shouldnt have to mess with the slider.

[CudaDon]

Pull off intake and check reed valve for damage or carbon holding one
or both off them open.
Don

[HoosierScooter]

O.K. What do I use as a cleaner for the reed valve? I do have Sea Foam.

[CudaDon]

First inspect them with a small flashlight for any gaps. They should be fully closed. If nec take the reed valve assy out of the case to inspect it. Be carefull not to break it. I usually go under it with a sharp knife. Inspect them with a light. They should be fully closed. If the are, they are OK. If there is carbon under them, you will need to clean it out. If they do not fully close, you might have to disassemble them. Be carefull doing this. Do not turn the reeds upside down when you reassemble.
You might need new gaskets.
Don

[HoosierScooter]

Last night I went to pull the carb for cleaning and was going to inspect the reed valve for carbon build up when I decided to fire up the scoot and go for a ride. I started out slow around 1/4 throttle and it was running fine. I continued for around ten to fifteen minutes. There seemed to be no problem. I continued to ride for an additional 30 minutes and occasionally my spree would sputter at higher speeds at full throttle. It would appear to begin to die but after releasing the throttle, it would return to operating well. I stopped for about 20 minutes and then went on a long ride with no problems. When I first started the scoot, I adjusted the carb some.

I'll probably take it out again tonight. I hope the performance is the same. I may have finally worked the Sea Foam out of the system.

[noiseguy]

Sounds like you're running lean. If it's not idling when hot, that jet's probably plugged, which would run it lean.

You should be running an inline filter, or at least the tank strainer. When you acid clean the tank, there are still bits of metal in the tank that will flush out over time. They'll eventually plug the carb, starting with the idle jet.

Your bystarter's obviously disconnected, which will make it hard to start without playing with the throttle when cold. I'd see about testing the bystarter and possibly reconnecting it.