cub still not starting

jeep258goat · Oct 6, 2011

OK, 50ish farmall cub. I reworked the valves, put back together everything and even put the plug wires on right this time. I got good compression now and i have spark going through the spark testor tool that you put on the plug and then into the plug wire. I believe i am at TDC, set the short side of the rotor button at #1ish position and then try to fire. I have put new point and condensor in and calibrated at the manual required spec. have good fresh gas flow at the carb. it is chugging with a puff of white smoke out of the muffler but will not catch and start. i feel like i still don't have timing or even the 6 volt system is not spinning engine fast enough. i am using original switch but if there was a problem here i would think i would not have spark at the plug? Need some more help on this one. I did remove the distributor from the tractor,,,could i have put it in wrong?

JRSutton · Oct 6, 2011

First thing to check, is to be SURE you're at TDC of the COMPRESSION stroke.

It's easy to forget there's an exhaust stroke, and a compression stroke.

Pull the plug on the #1 cylinder (closest to fan) and put your finger on the whole to feel for the compression.

One the exhuast stroke, the exhaust valve is open, and there's very little pressure build up in the cylinder as the piston comes up.

On the compression stroke, the pressure increase dramatically and can easily be felt.

THEN watch for TDC at the top of that stroke.

gene bender · Oct 6, 2011

is it a mag or a dist as you arent in time or it would start. You can remove #1 plug and with sw on and wire to plug with plug laying on head you can put your finger in the hole and turn engine over when you feel compression the plug should fire this will help to see if your are in time i do this all the time as it tells me i do have fire on compression at TDC

jeep258goat · Oct 6, 2011

it is distributor. new point, condensor, cap, plug wire, plugs added

i really believe i am not at true TDC. I am going to try again...any good tricks to give me confidence on the TDC?

El Toro · Oct 6, 2011

Mark the notch on the damper pulley with some chalk. Remove the sparkplug near the radiator and hold your thumb over the plug hole while a helper hand cranks the engine until you feel pressure against your thumb. Have the helper to keep slowly cranking the engine as you watch
for timing mark with the chalk until it's aligned with the pointer.

Then see where your rotor is pointing. It should be at the No1 plug tower which is about 2 o'clock. If it's off you need to pull the distributor and rotate the rotor so it's at 2 o'clock and reinstall it. Hal

DanR · Oct 7, 2011

If you R&R the distributor, which seems to be the problem, it will not be in the same position as it was on the bench. Because the gears are not straight cut you will have to back off the the rotor shaft so it will align back to #1 when it's put back on.

Larry in WNY · Oct 7, 2011

Are the spark plugs getting gas on them? If not remove the metering jet on the side of the carb. and clean it. There is a very small hole that could stop fuel from getting to the engine. I troubleshooted everything to get my Cub running and this was the problem.

Larry

smallercrawler · Oct 7, 2011

gene, thanks for a great tip! I'm having similar problems on an F124 Continental and hadn't thought of this way to check timing. Thanks again!!

jeep258goat · Oct 8, 2011

Wanted to give everbody who helped on this a BIG thanks as we did make the parade! Cub is timed and ran good. I am having a little steam out of the radiator area but we can take a look and get that fixed i am sure.

cub still not starting

jeep258goat

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JRSutton

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gene bender

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jeep258goat

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El Toro

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