here's another tip to improve spark on any magneto.

clean the mounting surfaces spotlessly clean and degrease with methylated spirits or electrical contact cleaner

get 2B pencil and rub it all over the mounting areas and reassemble this will put a fine coating of conductive graphite on the surface improving its contact and the return path to the magneto. blow off any excess with your breath. this is why any gaskets or spacers for magnetos should be metal such as shim brass.
(current path is from mag to plug wire to plug core to plug body to motor casting back to the mag)

you can also rub the pencil LIGHTLY on the plug terminal and on the plug and head seat mating surfaces ONLY.

DONT get it anywhere else or the plug wont fire.

this works well, I have done it on stationary engines an old mechanic showed me

Very intersting tip trainkidz. I will keep that in mind.
So I was excited to try my pony out before the weekend so I put it all back together this afternoon and it still doesnt run worth a hoot. I have avoided gasoline like the plague and now its biting me in the butt. So what happens is that it coughs hard if I open the throttle fully. I have to ease into it to minimize the hesitation. It wont pull rated RPM driving the main under compression. I can see it is not the governor holding it out. It seems to be a carb issue. Ideas? Thank you very much in advance!

My D2 5U pony started doing that a year ago, one day running sweet, the next day unable to get up to high idle, and certainly not able to crank the main under compression, I've tried everything, new fuel, triple flushed the fuel lines in both directions, new plugs, new wires, swapped wires, swapped in another good maggy, triple checked timing, swapped in another carb, tried squirting raw gas down the throat while the motor was running, pulled the heads to check the valves, and compression which was within 2 or 3 pounds of each other, even had our inhouse expert on everything "BruceOz" have a look for a few hours, he couldn't solve it either.

A top Cat Mechanic buddy suggested it's possible the valve lash has closed up on a cylinder, and that issue shows up worse as RPM increase, or attempt to increase, I haven't time to pull that pony yet, but what I do is open #2 cylinder head pet cock as the motor is idling trying to pick up speed, and that seems to help clear the motor so it can get going, it's still not right, but I can put up with it for now, #2 seems to be the problem cylinder on my pony.

I need to pull that pony motor one day anyway, I know the rear oil seal is shot, and there is some old scoring in the bore of #1 cylinder, the compression from memory was in the 60's, which is plenty, your issue sure sounds like a fuel problem.
Good luck
Mike

Mangoman wrote:

Very intersting tip trainkidz. I will keep that in mind.
So I was excited to try my pony out before the weekend so I put it all back together this afternoon and it still doesnt run worth a hoot. I have avoided gasoline like the plague and now its biting me in the butt. So what happens is that it coughs hard if I open the throttle fully. I have to ease into it to minimize the hesitation. It wont pull rated RPM driving the main under compression. I can see it is not the governor holding it out. It seems to be a carb issue. Ideas? Thank you very much in advance!

-why are you avoiding gasoline??

-a gasoline engine coughing, especially back thru the intake tract....is a huge red flag....too lean....or too cold yet....
-are you letting pony warm up some...esp since it's November and cooling...

-not pulling a load at rated RPM....also a sign of leanness...power takes fuel...no getting around that..

Have you tried choking it while it's under load?

Just wondering, Daron

Mr Pouce Coupe,

Maybe I will try dialing the main passage screw. Allow it to draw a little more fuel. See how it goes. I appreciate the simplicity of diesel. It is an exact amount of fuel injected and no ignition. I've had around 15 diesel vehicles and three gassers. Never had much appreciation for them but I suppose now is a good time to learn!

Daron,

Yes I did try choking but didnt help.

Dang thing starts right up nicely and idles well. Just stumbles when you crack the whip and labours in an attempt to bring the main to proper cranking speed. I had a brief taste of it running well and I want that back!

Thanks for the suggestion Niel. I did run it on my Bosch mag and it seemed about the same. Has new solid core wires and I tried it with new NGK AB6 plugs yesterday and it didnt make a lick of difference. Not sure how legit of test it is, but the manual says to hold the lead 1/8" from ground. It jumped it no problem with a fairly lazy tug on the cord. Hmmm....

-a gasoline engine coughing, especially back thru the intake tract....is a huge red flag....too lean....or too cold yet....
-are you letting pony warm up some...esp since it's November and cooling...

-not pulling a load at rated RPM....also a sign of leanness...power takes fuel...no getting around that..[/quote]

New board is not so helpful since it hides your location until you click the right spot, but Mikey is down under so it is springtime and never the cold white stuff like in the north. That is the trouble with this international community you cannot over generalize. But still the mystery of the pony, they can be such devils to get right sometimes.