model steam engine question

Got a Stuart vertical engine, model 10v, piped up to a PM Research boiler. The engine runs great 5lbs of air but will not run on steam. Good dry steam comes out the exhaust but will not run. Opened up the steam chest and nothing blocking the ports. Any ideas, suggestions or tips?

Thanks Jim

Reply to
jwolgamuth
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Tell us some more. How does the engine turn when you turn it over by hand? My only guess is that the heat is making something expand and therefore it cannot turn. Do you have a pressure gauge on the boiler? What pressure are you applying?

chuck

Reply to
Chuck Sherwood

Reply to
David Billington

When turned over by hand it has some compression which it retains when I flip it over while opening the throttle. Not sure about the pressure, no gauge, but same set up will run my Stuart number 9 mill engine no problem.

Thanks Jim

Reply to
Jimbo

It has compression when turning it over in the same direction that the steam should be forcing it to turn???? Sounds like the valve timing is off.

Reply to
Chuck Sherwood

But it runs fine on air. Maybe the steam is cooling down before it can do work?

Reply to
Rex B

Reply to
Scott Henrichs

Chuck Sherwood wrote: Sounds like the valve timing is off.

I have read info on various Steam sites that indicates valve timing should be 10 degrees Earlier on Steam engines compared to Air powered ones....... I would think it would run either way, but give a look anyhow. Something doesn't make sense.......

Grummy

Reply to
grumtac

wrote (clip) Something doesn't make sense....... ^^^^^^^^^^^^^^^^^ What bothers me is that all the obvious answers we have been offering ought to be obvious to the OP. When you open the steam valve to the engine, and it doesn't turn, you turn it by hand. Is there any indication that steam is entering the cylinder and coming out the other end? Does the cylinder get warm? Does it drip water? It seems like it HAS to be a blockage somewhere in the supply. Can you crack a connection and have it hiss at you?

Reply to
Leo Lichtman

No matter how you turned the flywheel steam was constantly shooting out the exhaust. Nice dry steam. So I re-opened the steam chest back up and found some grit/goop in with the slide valve. Just a tiny bit but after reassembly the engine kick off and ran great. Guess maybe the goop was keeping the valve from sealing tight and I just missed it the first time it was opened. Not sure why it would run on air though. Just glad to get the engine running on steam. Thanks for everybodies' suggestions and help.

Jim

Reply to
Jimbo

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