It kept going

So here's the story.

Last night I cleaned out the carburator on my Batavus Regency that I just got. It ran, but the throttle was stuck, as it seems to keep doing. So, today after I finally got the throttle slide to move alright, I took it for a ride. Success, a perfect running moped, or I thought. As I pulled back into the yard I realized the throttle was stuck open again. I put it up on the stand and immediately the thing rev's up to warp speed, and it was LOUD. I've run it before, and it has never been that loud or such a fast revving. Next, I reach for the kill switch to shut the moped off. But it doesn't shut off. It just keeps going. In fact it continued for about 30 seconds. I flipped the switch twice more and nothing. So, thinking the switch is bad I decided just to pull the spark wire off. Little did I know that the engine had become so hot it was melting the rubber cord, and the cord just slipped right out of the metal end, and rubber joint. In awe, I simply watched the engine smoke for about two more minutes. After it cooled, I checked the spark plug and it was a nice tan color.

So, first, why would a moped rev up so freakin' high, and get so damn hot?

And how do I get the throttle to quit sticking?

I don't know if the switch was bad, it has worked fine before. Or, can a moped engine get so hot it starts a dieseling reaction?

Besides all that, I know it's alot, earlier this week I couldn't get any power out of it. It would just bog down, or go about 10.

Kind of confused,

Brendan

Re: It kept going

all i can say is that its wind cooled and when your driving at high reves the wind cools it douwn when you have high reves when on the kick stand it has no wind to cool so it gets hotter and hotter.BILL

Re: It kept going

See Ya Moped Army /

It seems to me that your moped got hot because the engine was getting too much gas....ie. your throttle was sticking open. Have you checked the thrttle cable to see if it's hanging up inside it's sheathing? Are there any kinks in the cable? Is the cable too tight? This will also cause your throttle slide to stick open. If none of these conditions are present, then maybe your throttle slide and/or the carb needs to be cleaned better. I soak my carbs in professional carb cleaner that I get at NAPA. If there's any varnish on that slide or inside the carb where the slide rides, it will hang up.

Re: It kept going

The throttle slide itself is sticking inside the carburator. I Cleaned it our real well, and sanded it a little too to make it smoother. But actually, I just went outside and the throttle is not stuck now. What the hell. Now I need a new spark plug wire.

Can moped engines start dieseling if they get too hot? I'm pretty sure the switch is fine.

Brendan

Re: It kept going

See Ya Moped Army /

It may not be stuck now because the bike has cooled down and the metal has contracted. When the carb/engine gets hot again, it may very well continue to stick on you.

Mopeds will make pre-ignition noises, especially if the timing is off.

MoPedlar

Re: It kept going

Pulling the choke lever would have killed it. It will also cool the engine a little, as heat is used up to evaporate the fuel going into the engine.

Paul

Re: It kept going

I've seen the Batavus switches fail before. There are two metal posts in the switch and a spring-loaded brass button that shorts the two posts in the off position. The posts and button corrode slightly and the connection is lost.

The switch comes apart and the posts and button can be cleaned with some 600 sandpaper. If you take one apart, just be sure to take the button out carefully, because the spring will cause it to fly out and you won't see it again. I had to machine another button once from a brass screw because the button flew out.

The turn signal switch works the same way.

Paul

Re: It kept going

You can also take off the head and see if there is carbon buildup on the piston crown or head. Sometimes a nodule or flake of carbon can glow red hot and cause knocking or dieseling.

Although the Batavus engines don't use head gaskets, a piece of gasket protruding into the cylinder could also glow red hot. I've seen head gaskets on Batavus engines where there shouldn't be one.

Check the spark plug type also. It should be a Bosch W175T1 or W240T1 or a NGK B6HS or B7HS or a plug with an equivalent heat range.

Paul

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