After sitting for a couple of months I tried to start my 1998 Xplorer 400 only to find that it has no throttle response. By that I mean that nothing happens when I give it throttle other than a throatier sound from throttle valve being opened. The motor makes no effort to speed up. The motor idles about as good as it ever did, and continues to idle for several seconds even on WOT.

Pulled fuel line off, fuel flows freely. Fuel had stabilizer in it. Checked vent lines; all are clear. Air filter is good. Choke fuel enrichment valve seems to work properly. Throttle valve works like it always did.

I pulled the carb and intend to clean it out and blow the passages. Is that the right thing to do first? Or is there something else I should check?

Thanks

 

Anyone? I've read many posts about poor high end performance, poor or no idle, inability to get past half or 3/4 full RPM, lack of power. They suggest possible causes as being bad reed valve, broken piston skirts, bad ETC, bad fuel, plugged carb jets, plugged air filter, plugged vent lines, bad compression, and a few other things. Seems like in all the posts I read the motor would rev up some. In my case the motor does not rev up a single RPM on WOT. It just gets a throatier sound from the throttle valve being opened, runs for about 10 seconds and dies. With no throttle it will idle for several minutes before it dies....which is what it always did. Motor starts very easily like it always did, almost instantly.

What is the likely cause? I'm hoping someone out there has experienced this before.

 

dirty carb from sitting up probably. sounds like the main is clogged not letting extra fuel to get pulled up.
while you have it out to clean it i would also check your reeds to make sure they arent warped.

 

Thanks. I'll proceed with cleaning the carb out. It's already off. I'll take a look at the reed valves. I assume I'm looking for a uniform appearance.

 

if you hold the cage up to a light you should not see any light coming through between the petal and where it rests on the cage. do NOT try to move those petals with your fingers. they are designed to only open a certian amount and if you try to open one of them further than what they are suposed to be you can either break it off or just bend it so that it doesnt close back up

 

Update: I cleaned carb out again and made sure all jets and passges were clear. Next I pulled the reeds off and checked piston skirt. Skirt is intact. The reeds are intact and uniform in appearance. One side of the reeds has a slight gap between end of reeds and the stop they rest on. By slight I mean a 16th of an inch or less. I can definitely see light through the gap. There is no gap on the other set of reeds.

One other thing I notice is that when idling I feel puffs of air coming out of the carb where air box attaches.

The Clymer manual I have is not clear about whether the reeds ends should be resting against the reed stop. Can someone please clarify this for me? Is the small gap causing the problems I'm seeing?

The weather is much too nice to have Big Red sitting in the garage. [img]i/expressions/face-icon-small-sad.gif[/img]

Thanks

 

aside from the very tip of the reeds you should not see any light coming through the reeds and the reed cage..the very tip of them do not touch anything. if you can see light coming from the other parts then i would say replace them. they need to be replaced anyways but not sure if this would cause your problems. it really sounds like a port or the main is clogged...with the carb out, try moving the throttle..there is a long pin in the middle of the carb body that should move up and down with the slide. does it?

 

On WOT I stuck my finger in carb and moved throttle. I can feel the needle moving up and down in relation to the slide moving moving up and down. I removed main jet a few days ago and thoroughly cleaned it with carb cleaner and compressed air. I was sable to see daylight through it. I did same with pilot jet today.

Still it's like it's not getting any gas. But it seems it is. I covered the intake with palm of my hand while it was idling and gave it WOT. Motor almost immediately died and my palm was covered with fuel where I have covered the intake with it. The fuel came from somewhere.

I'm really stumped.

Thanks for hangin in there with me on this.

 

While idling I used a mirror to watch the slide and needle while giving it WOT. I can see fuel spewing toward the reeds when I give it WOT. Absolutely no response from the motor other than it dies after a few seconds like it's starved for fuel. It cranks right back up on idle. It will not run at all on any throttle setting other than idle and WOT.

This is weird.

 

Bingo. It's the reverse override switch. Push the switch and it runs like it used to. [img]i/expressions/face-icon-small-smile.gif[/img]

Any tips on how to disable the thing?