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W400

1936 td 40

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Any experiences or theries appreciated.

Rebuilt everthing on this engine 10 years ago always started 4th crank since it started and ran great back in sept tried it mid Jan wont start somtimes will fire 3 to 8 revolitions then quits valve cover has been off all valves working ok compression feels good on crank handle striped and cleaned carb looked ok changed mag for known working mag old mag also checks out  removed intake manifold new gaskets thinking vacum leak all looked good decided timing must have moved?jumped? no looks ok and it is fresh gas or is modern gas so bad it is no use in these old engines? spark plugs cleaned and swaped. thinking it has to be fuel problem am i missing somthing in carb??

Thanks for Now

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Since you removed the carb for cleaning, I would check for sticky float or needle valve. WIth full starting tank, set engine on gas cycle and remove the drain plug on bottom of fuel bowl. Place a container under the flow and make sure you have a good steady flow for several minutes, or tank drains out. Check the drained fuel for water and rust particles.

It could be a sticky poppet valve in the intake manifold above the barb. you can pull the top cover and clean and lube the valve stems, making sure the valve seats in both start and run positions. lube all the linkage pivot points also. 

Could the timer on the fuel pump be tripping the decompression lever too soon?  What does the exhaust look like for the 3 to 8 revolutions when it does fire? Sounds like you are close. Jim.

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1 hour ago, crawlernut said:

Since you removed the carb for cleaning, I would check for sticky float or needle valve. WIth full starting tank, set engine on gas cycle and remove the drain plug on bottom of fuel bowl. Place a container under the flow and make sure you have a good steady flow for several minutes, or tank drains out. Check the drained fuel for water and rust particles.

It could be a sticky poppet valve in the intake manifold above the barb. you can pull the top cover and clean and lube the valve stems, making sure the valve seats in both start and run positions. lube all the linkage pivot points also. 

Could the timer on the fuel pump be tripping the decompression lever too soon?  What does the exhaust look like for the 3 to 8 revolutions when it does fire? Sounds like you are close. Jim.

Thanks Jim Poppet valve is lubed and I think good working order to but I think your gas flow check is on the right track will check this. couple of times I opened drain to check for fuel after it quit to make sure it was not dry.  Fuel flow was not great have had feed pipe of and glass bowl cleaned good flow to carb.

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W400, There should be a brass screen in the inlet fitting to the carb. This can plug up with debris. Also make sure no rust or leaves are floating in the tank. If the sediment bowl stays clean thru a wide open flush cycle, Tank is probably clean. Hard to see into tank with the offset filler neck

Does your engine have the priming plunger to pull gas out of bowl and spray it into the manifold? They are spring loaded. Just pull back and will deliver some extra fuel for cold weather startups.

Did you replace or reuse the gaskets in carb and mounting flange? Might want to check for vacuum leaks in these areas. Jim.

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Well its been 9 months since I last walked past the crawler never got time to go back was showing a friend around the shed on stormy day 12 30 2017 we got to discussing the cant start wont start said I hadn't had time to look at it he had a quick glance and said autolite plugs are excellent but being bare metal and sitting doing nothing for months maybe years they rust between threads causing bad connectivity I said I had them out but did you clean the threads he asks, so we set to it cleaned the thread holes with hole wire brush scrubbed the plug threads they were dusty with rust fresh gas plugs reinstaled, full choke 4 cranks to time (connect engage magneto) moved to half choke 2nd crank and running sweet as a nut . had the change over lever dissconected ran on gas for a while. switched here off turned on diesel reinstaled change over set  fuel pump timer to max she fired 3 rd crank ran sweet and switched automatic to diesel sounding very sweet.

Happy new year to me. and to every one  else of course.

Guess the story is true there is often more goes wrong with this rusty old iron sitting doing nothing than there is working it alas that is what its for i suppose.

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Glad to hear it's running well... I'd be surprised if the plug threads were the issue, but something you did worked .. and that's what matters .. 

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W 400,  Glad to hear you got the machine running. That is a nice way to end the year and begin the new one. Jim.

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