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Thread: choking the pony, or are you?

  1. #1
    Join Date
    Nov 2006
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    Hood River county, Oregon.
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    757

    Default choking the pony, or are you?

    I set out a couple days ago to put the tooth on my D2 5J and lift some small stumps, but I could not start the pony. I tried the usual things, primed the cylinders through the spark plug hole, etc. A few pops, no start. Obviously, I would have to put in a half day of remove, clean, reassemble. You've all been there.

    I did the usual cleanup, found considerable sediment, blew out all the passages, nothing unusual. Now I'm sure the carb will function, but before I put it back on the engine, I worked the choke control. The choke worked through the full scope of it's movement, but the choke plate didn't move a bit! It was just enough stuck that the spring that closes it would not move it. A good flushing of the choke bearings and shaft solved the problem; I went ahead and put it together. It starts like your fondest dream come true. Roll it over about three turns to prime, then one good pull and I'm in business.

    Then I thought of all the gripes about her-to-start pony engines I have heard, but I don't recall any advice about checking this simple device that makes all he difference in the world with the starting mixture. I can't recall any advice about checking choke action on this BB or anywhere else. And I can't recall anything so simple that makes such a difference on an otherwise good engine. Have I just missed it? I must have. I cannot believe that it hasn't been here at some time.

    Anyway, if the pony's hard to start, make sure you really have a choke!

  2. #2
    Join Date
    Nov 2006
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    McBEE, SC
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    Default

    That is a good tip. I wonder if that had been a problem back when, since I've seen a lot of later style carbs that didn't have that external mechanism but used a relief mounted on the plate itself. I don't know when Cat changed specs.
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  3. #3
    Join Date
    Aug 2019
    Location
    Washington
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    Default

    I feel like the general consensus with pony motors is those pull knobs are mostly for show.

    However, when I go to start my pony, depending on atmospheric conditions I may or may not have to pull the choke out.

    The first time I really made use of the choke I thought it didn't really do anything, but one day I got the pony turning and it was starting to sputter out. I decided to pull the choke and it came back to life.

    I believe when you pull the choke out and push the choke back in, the engine is still "choked" until it starts turning.

    Those times when the pony won't start within 2 or 3 pulls, I pull the choke out and it usually starts on that pull.

    I believe throttle can be a useful tool too. If your starting pinion is out of adjustment and pops out at full throttle, you can reduce the throttle so it doesn't turn as fast while still being able to start the diesel.
    Cat D6 5R

  4. #4
    Join Date
    Nov 2007
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    NW Ohio
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    Default

    Yea....the throttle is also very usefull to let the engine idle when cold and circulate the oil so the main and rod bearings dont go out for pilot license! Also to idle down to cool the valves. But most dont understand this concept and assume that all starting engines are ran full throttle all the time. Makes you wonder why they dont start there car, pickup, farm tractor or semi with the throttle mashed to the floor or wide open? might as well!
    Last edited by Rome K/G; 03-21-2020 at 02:19 PM.

  5. #5
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    "Stupid is as stupid does"
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  6. #6
    Join Date
    Aug 2019
    Location
    Washington
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    Default

    Quote Originally Posted by Rome K/G View Post
    Yea....the throttle is also very usefull to let the engine idle when cold and circulate the oil so the main and rod bearings dont go out for pilot license! Also to idle down to cool the valves. But most dont understand this concept and assume that all starting engines are ran full throttle all the time. Makes you wonder why they dont start there car, pickup, farm tractor or semi with the throttle mashed to the floor or wide open? might as well!
    Hehe, people seem to live and breathe pony motors when it comes to these old tractors, but would never treat their pony motor the same way they treat starting the diesel. XD

    It probably would be nice to have some knowledge floating around as far as running the pony motors as what I know is pretty much a result of me just going "I wonder what this does?"
    Cat D6 5R

  7. #7
    Join Date
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    Pittsford NY
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    Default

    The choke on my D2 only has the spring relief pin on the butterfly, so wherever I place the control, that's where the butterfly is. Mine requires choke to start but I have my carb pretty well-tuned so it's only running slightly rich but I can push the choke most of the way in as soon as it fires and after about 30 seconds in this 30 degree weather, it'll idle without choke. I finally managed to adjust my pinion so it holds at full throttle as the main engine is trying to start, but I can see your technique of backing off the throttle a bit if the pinion's out of adjustment - just need the main to be able to start at lower rpm : )
    Cheers,
    Neil.

  8. #8
    Join Date
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    Lancaster CA
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    With the poor splash oil system on ponies, you should put them down to idle as soon as they start and leave them at idle for at least 30 seconds to insure all bearings are well oiled before putting a load on them at high speed.
    Cat 12 grader, 8T6995 running and restoring, Cat 12 grader 9K3585. parts machine, Adams leaning wheel Pull grader Mod # 22, ser#438

  9. #9
    Join Date
    Nov 2006
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    Hood River county, Oregon.
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    I did a job on another man's 5J over in Washington some years ago. He was putting a v-belt around the flywheel and cranking it with an old car starter of some sort. When the pony started, he had to slam it into gear because it would immediately overspeed. The splash oil system must be reasonably good or that motor would have gone to pieces at any time!

    On inspection, I found that he had no functioning governor at all. It had shaken the mounting apart, thrown the governor drive belt, and gone straight to wide open. Too many of us abuse those starters way beyond anything they should be expected to withstand, but in his case it was a case of unfamiliarity with the equipment. When I got him set up with a rebuilt governor, that was one of the sweetest running pony motors I have dealt with, and he was very happy to pitch the belt, battery and car starter and buy a piece of rope. And he didn't balk at the price of the work at all!

    (It involved a severely out-of-balance casting and is still in old threads posted by Jack if you are interested.)

  10. #10
    Join Date
    Feb 2016
    Location
    southern NSW Australia
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    109

    Default

    My D2 Starting Engine was starting, running and Idling great after a full carby rebuild. But recently became hard to start and un-responsive to throttle adjustment.
    Still doesn't require choke and has loads of power but wont run at low rpm.
    Can anyone help with this?,
    I have removed and cleaned fuel supply lines which were already clean.
    The fuel is fresh and not stale.
    Regards

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