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D7 3T pony motor not starting

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8 months 2 weeks ago #248984 by josh
Replied by josh on topic D7 3T pony motor not starting
I will get back to you after I get a chance to clean it up a bit tomorrow. If you are still having to hold your hand over it to keep it running, it almost always means the passage to the main jet or the jet itself is still clogged.

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8 months 2 weeks ago #248985 by V14
Replied by V14 on topic D7 3T pony motor not starting
I'm pretty positive the passages are clear but may throw it in the ultrasonic cleaner again at a higher heat. Either way still interested in the upper since my choke shaft issues are still present. If you don't mind responding here when you message me I can't figure out how to make the messages send me an email like the posts do.

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8 months 2 weeks ago #248996 by josh
Replied by josh on topic D7 3T pony motor not starting
I sent you a test email and PM through the ACMOC system, did you get either?

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8 months 2 weeks ago #248997 by V14
Replied by V14 on topic D7 3T pony motor not starting
Got the PM but not the email.

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8 months 2 weeks ago #248998 by josh
Replied by josh on topic D7 3T pony motor not starting
Often to clean out the passage ways on a carb, you have to drill out the plugs at the outside ends of the passage ways to access them for cleaning, then replace the plugs with lead shot the necessary size to reseal.
The following user(s) said Thank You: kracked1

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8 months 1 week ago #249106 by V14
Replied by V14 on topic D7 3T pony motor not starting
Swapped out the carb top and that fixed the choke issue but still won't run without hand choking. I'm certain all the passages are clear, float height is measured and good. Even sprayed outside the carb while hand choking it and there is no air leak at the carb it maintained the same throttle rate. Seems I can rule out the the carb itself.

Would it make a difference if the gas line comes from the top instead of the bottom/side? The rebuilt carb i saw has the gas inlet pointing down and the cat part book shows it horizontal, mine comes from above. Doubt that makes a difference but could it just be pulling in so much gas because of lack of vacuum and flooding it? 

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8 months 1 week ago #249116 by ctsnowfighter
You are using your hand to restrict the air intake on the top of the carburetor - in effect using your hand as a choke.
Then you contradict yourself -
Could it be flooding? If it were flooding, you would be rich already and not need your hand closing the intake which richens the mixture.
Hand on the intake to keep it running says LEAN!

Did you follow instructions and ensure the lead plugs were drilled out and the passages are clean? Then the plugs replaced.

The direction of the line coming into the carburetor is inconsequential. The fuel from the tank to the carb is all higher in elevation than that inlet. The NEEDLE & SEAT controlled by the FLOAT determine how much fuel is in the carburetor bowl. Too High it will flood, too low you will not get enough gas to run.

You need to find some reliable/knowledgeable carburetor shop to help you with this rebuild and then have someone help you with the installation and adjustments.
Certainly there must be some mechanics that are "old school" and understand carburetors.

You are dealing with an out of service life machine, parts are difficult to find, This requires improvision in many cases.

CTS

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8 months 1 week ago #249118 by V14
Replied by V14 on topic D7 3T pony motor not starting
Main reason for that line of thinking was that it will start choked. When started open the choke then I have to hand choke for a second it runs good for 5 to 10 seconds then another quick hand cover and runs fine again for that long. The old spark plugs were black indicating it was rich not lean. When fully choked and running its sputtering open choke and do a quick hand blip and it runs at speed. I do not need to hold over it constantly to keep it running and if I do that it dies. 

Carb passages are clear new plugs for the body were in the rebuild kit that isn't an issue. I can shoot carb clean through every passage and it comes out the corresponding passage clear and quick. Another oddity is that if the exaust manifold hole we talked about before is plugged by a stick it will not start at all if unplugged it will start. 

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8 months 1 week ago - 8 months 1 week ago #249119 by bernie
Can’t recall…was plugged / kinked fuel line discussed? Clog at bowl or filter-tank outlet? Type of fuel line, (rubber or steel)? And if the connections are tight and not leaking air. If rubber, is it fuel grade?

Free flow out of bottom of carb I believe was mentioned. Is bowl full immediately after it dies. Spray soap water around carb and line connections look for bubbles. In-line filter changed? Eliminate inline filter? Is the machine on an incline?

No doubt on a thread this detailed these basics are covered-as info on my 2TD4 the throttle linkage can snag up on my choke lever.

Good luck-mucho info tangled on this thread.

Keep safe-
Last edit: 8 months 1 week ago by bernie.

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8 months 1 week ago #249120 by V14
Replied by V14 on topic D7 3T pony motor not starting
This was not discussed, fuel flows freely through the line but there is a spot near the carb inlet that is nearly flattened, didn't think it mattered since fuel flowed well still. It is a metal gas line not rubber. Everything was tight no air or gas leaks that I can find.fuel bowl is clean tank is clean no sediment showing up in the fuel bowl or carb when taken apart. No incline filter just the original glass bowl and filter screen in the carb inlet. That was clean when I switched carb tops. I have noticed the throttle linkage can get caught up but for me it was on the spark plug wire not the choke lever. It moves freely now and can see it moving when running, only locks in when I force it to for cold start.

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