Thu Sep 13, 2007 8:20 pm

I dried off the plugs and plugged the wires on each plug, layed the plugs on the maniflod loose, then cranked the engine. Each plug has a nice blue spark.

Yep John, checked the spark, but I'm not sure how to check
form the plugs at the right time?
If the correct order is 1342 and I have them in that order on the cap, clockwise, how can it be off, or am I not seeing something?

I keep going over and over, thinking I might be overlooking something but I just can't see it. The guy that owns the cub said the same thing. He just couldn't figure things out. It shouldn't be that difficult to find the problem :shock: .


Thu Sep 13, 2007 8:23 pm

pull #1 plug, and check when coming up on TDC. make sure #1 plug fires when #1 cylinder reaches TDC. The plugs should fire 1-3-4-2. right around the cap (clockwise from the rear).

Thu Sep 13, 2007 8:26 pm

Rick.......I'd try the starting fluid. John.......he did mention blue spark at plugs. If it won't start with a little starting ain't gonna' start. I'd agree to placing your hand over the carb to check vac. Sounds like you got the combustion triangle........someone mentioned safty switches?
Last edited by splicer on Thu Sep 13, 2007 8:28 pm, edited 1 time in total.

Thu Sep 13, 2007 8:28 pm

Gas to the Carb, spark to the plugs (bright blue), timing is correct enough, compression is excellent...Seems like the most logical explanation with what you've stated is no gas to the combustion chamber. Will be interesting to see what new gaskets do. By the way, is the manifold badly warped, or cracked?

Thu Sep 13, 2007 8:36 pm

I know this is very basic, but also easily overlooked, Is the gas fresh, and is it gasoline and not something from the "wrong" can? If there is fuel, spark, and compression all at the correct time, it has to run.

Thu Sep 13, 2007 8:37 pm

what aobut valves, it only takes one leaking intake valve to prevent starting.

Thu Sep 13, 2007 8:43 pm

John.......I was just thinking about the valve train, as that was what prevented my dad's from starting when we got it. Your always thinking!

Thu Sep 13, 2007 8:48 pm

Rick, with my 184, I had a hard time starting it and I discovered that the fan pulley was creating too much resistance. I forgot whether or not it needed lubed, or what. I removed the fan belt and it started. I know it sounds screwy, but that's what happened. Larry

Thu Sep 13, 2007 8:56 pm

Thanks Bill,
Did you hand coke with the hose off the carb as a shade tree way to check for vacume? When I see the circle on the palm of my hand and some gas I get a clue or two.
and yes, when I went from the Zenith 184 carb to the IH trencher carb, the air cleaner hose no longer fit the smaller IH carb, nor did the choke cable from the Zenith. I held my hand over the opening just to choke it temporarily and there seemed to be plenty of vacuum.

When I started today,the cub was out of gas from setting this summer, so I went up and filled my 2 1/2 gallon plastic can with fresh gas, so that's out :D

The head looks good, and I now have the manifold completely cleaned up. It looks like it was slightly warped in the center between 2 and 3 exhaust, but now it's flat and ready to go back on, soon as I get some gaskets from TM. Just seems like it should have popped or something, the manifold wasn't that loose to completely fail, I don't think.

Somehow I want to check the timing between the crank and the cam, to make sure things are where they're supposed to be, just for piece of mind, since the obvious hasn't shown up with everything else.


Thu Sep 13, 2007 8:58 pm

I know this would be a stretch, but is there a blockage in the intake or exhaust, either not letting enough air get to the carb, or preventing exhaust from getting out. Since the engines use such little gasoline, either could bind it up easily and keep it from having enough air to fire on.

Another thing. On the 63 lo-boy I had the exact same thing. Cranked and Cranked and it just would not fire. Turned out that the on/off key switch was not making contact. That should eliminate the fire, which is why mine would not fire, but it gets more to the point of ignition switch and safety switches. Sometimes you think you have bypassed them, but one is still tripping you up.

Anyway, just a couple of thoughts.


Thu Sep 13, 2007 8:59 pm

Rick I'm thinking vacuum leak had the same problem it had spark was in time and plenty of gas. But it would run on starting fluid. Give it a shot of starting fluid and see what you get.

Thu Sep 13, 2007 9:07 pm

but is there a blockage in the intake or exhaust, either not letting enough air get to the carb, or preventing exhaust from getting out

Bill, I'll check the manifold better tomorrow. I looked into the ports and didn't see anything, but guess I should blow air through to make sure. This thing sets in a barn, so the mice could have some homes built inside the muffler maybe.

Once I get it back together, I'll try the propane or starting fluid trick to see if anything happens.


Thu Sep 13, 2007 9:08 pm

Hi Rick,

Mine went through a spell one time where I had to put my hand over the carb to act as a choke and it would start. Wouldn't do anything till I did this. It had real good suction too. Wouldn't ever do anything with the tractor's choke on. Had to hand choke it. Just a thought.


Thu Sep 13, 2007 9:12 pm

Jim.......I think he's been there........done that. We're all waiting with abated breath to hear the ending of this epic saga, If it's got Rick stumped............

Thu Sep 13, 2007 9:15 pm


Time for some silly input from a knownudink...... but gonna give it a shot.

Now this is on a mag equipped Cub.. but should be similiar to a distributor, cause it does have to do with timing. Could the rotor be off one tooth :?:

It was with Granny. Cecil and I played with that for a couple hours.. precious time when you only have basically 2 part days to play... Didn't matter what we did. Coil, points, rotor, condensor, plugs, TDC, check for compression and not exhaust stroke.. we did it all.

Then Cecil said.. I wonder if it was the same thing Bill mentioned on the Zagray Power Unit.. rotor off one notch. We said nah.. that couldn't be it. Played some more.. still no luck. Said the heck with it, went and checked the rotor .. and yup.. off one notch. Aligned it and presto.. ignition :!: :roll: :wink: :oops: :wink: :D