1998 1100 stx won't idle

[bhale5]

I have a 1998 stx that I have bought and put back together. It won't start unless it is choked out all the way. This is the case no matter if the engine is hot or cold. When I do get it started it will idle for about 30 sec and either die out or race away. when it does this I can press the kill switch, pull the lanyard, and pull the plug wires and it still doesn't stop. The only thing that kills it is choking it out again. Any input would be greatly appreciated. I don't know where to start looking. Thanks.

[123456]

when it runs away pull lanyard and hold throttle wide open.

did the ski just become hard to start ?

when was the last time it ran well ?

[nmpeter]

don't run that engine again till you've gone thru the carbs and are sure the fuel is being delivered. check the return hose when cranking, you should geta good fuel flow out of that. The runaway is a very lean condition that can burn a piston in no time at all!

more details about the condition when purhcased and the work you've done ( use new gaskets on teh carbs and so on?) will help us help you

[bhale5]

This is a ski that I inherited with a bad piston. I replaced it and have cleaned out the carbs thoroughly. I didn't rebuild it. Everything looked to be in good shape other than gummed up a little. I didn't replace the base gaskets. I've got them on order so maybe this is the problem. Also the carbs have had the choke removed and a primer system hooked up.I've also got plenty of gas coming from the return. FYI I'm running premix along with the oil injection and it still runs away. Thanks for the help

[123456]

oil in gas and using oil injection will not cause a two stroke run away.

[nmpeter]

I didn't replace the base gaskets.

The keeper of internal combustion engines is ready to see you now....

<royal march soundtrack>

You What?

I see....

Those pesky metal gaskets are tempting to reuse. I'd love to know what the were thinking with the pegged design and all metal

Replace the gasket..air leaks in this area(and most others) simply cannot be tolerated. Don't take much to toast the engine.

[bhale5]

I know. Should have replaced them. Is this the likely air leak. I've got them on order. Never again shall I reuse gaskets. I will spread the word

[nmpeter]

runaway from a lean condition in your case is likely an air leak at the carb manifold, as it appears there is no problem with the fuel flow on the return line. Gaskets should resolve it. try to check the carbs for flatness... use a brass brush to clean it all up prior to assembly I use red high tack on stuff like that.

Be ready with a shop rag to choke off the engine next time you start it. Good prep is truly essential for this one

[bhale5]

Thanks for the input. I will post after I change the gaskets out. Thanks

[bhale5]

I changed the gaskets out. It still is hard to start and doesn't idle for long but it hasn't run away again. It will run for awhile if I keep pulling the throttle but eventually will stop. How do I know if it's getting enough fuel? It has fuel coming out of the return but maybe it's not enough. Any thoughts? Thanks