1/4 perkins won't stay running.

[fallnhorse]

I'm building a perkins hit miss from castings. I have tried to run in on white fuel and propane. I get the exact same results. Runs pretty good sometimes for 10 second, then start hitting every 5 - 8 cycles going too slow to trip the governor. THen it konks out. I thinking maybe valve sealing? Not really sure. Exhaust goes on just before bottom of the stroke and off at the top of the stroke.

also tried to enrich the mixture, plus lean it. Couldn't tune it in.

Kind of has me stumped. I hand to repolish the exhaust valve to get it to start to run. I'm wondering if i need to do the same for the intake.

So close it's frustrating. But i know i'm close.

 

[Cogsy]

Sounds to me like fuel starvation. It gets a dose of fuel and runs on it then can't get enough to keep going. Is your fuel tank height just below the height of the carby? If the tank is too low it may have a hard time pulling the fuel uphill.

Or possibly you're getting an intermittent leak on your intake valve. I know I've had intake valves be a bit finicky at first and occasionally refuse to seal every now and then. Normally I just tap it a couple of times with my finger and it will reseal. This goes away fairly quickly after the engine starts to run though, as the combustion force 'fixes' the valve seals somewhat.

 

[fallnhorse]

Right now using propane demand valve, a howell design. I will try to enrich it more. I have to choke it to make it run. So you're problaly on the right track. Perhaps it's not feeding fast enough. It's only hit every other every revolution at best. Rarely will hit every time, Very irractic power...First time Strong. Next hit weak, and weaker and weaker, Then stalls.

Hmm does sound like running out of fuel.

When using white fuel it would puff black but when trying to cut fuel back it would die out.

I switched to propane because it's sure a lot less mess and doesn't stink up. Runs a little better on it.