whats the deal with this stupid zen 231

[wingtip]

Ive had problems with this motor since i bought it new (from century)... before, it would have a rough time starting but would run... and run somewhat ok..but after yu shut it off it had a terrible time starting again...
i just put in a new main gear from min for testing and the dam thing wont start period...

1) yes its getting fuel (it sprays fuel when plug removed,even shot some in cylinder from top of head with syringe)
2) yes its getting spark, can see it spark with plug removed and grounded to block
3) yes the plug is gapped properly and tried the same type plug from another machine that was just running AND put my plug in that machine and ran fine.
4) fuel mix is 58:1 (2 oz per gallon) on coleman camping fuel

yet it will not fire a lick now.... whats the deal? if it gets spark it should fire right? or can it spark and still not be a srong enough spark for running?

gonna try to borrow another secondary coil, and carb off another motor and see if i can narrow it down but this is starting to piss me off when my buddys (exact same config as mine fires every time and runs great...

but, since im just now gettin round to getting some serious run time on it i dont know if i can get a warranty/exchange on any parts since it was actually bought 11 months ago... has 2-3 gallons time on it....
someone help me before i take a sledgehammer to it... and plz no guessing... i need solid answers.

[Gary Travis]

Dave check the air gap down on the flywheel, I had an engine and the secondary coil was loose. sometimes it would start and some not. I regapped the coil to flywheel and problem was solved
Gary

[wingtip]

i will check that compared to the other motor when a buddy drops it off...i still have to pull the mechanics back out of the fuselage :arggg:

[CustomPC]

I'm definately no expert but here's 2 ideas you can check/try

Are you using the Z-RC aluminium insulator block?

I'm using one and i had similar symptoms to what you desctribed from new. When i pulled the carb off to look at it i found that i had installed the teflon gasket between the insulator block and carb on backwards. The gasket was partially blocking the pulse hole.

Have you tried regular gasoline instead of camper fuel? Mine definately has more ooomph if i use regular gasoline rather than camper fuel.

[cbergen]

Do you have the braided sheilding over the spark plug wire? Try removing it....

[wingtip]

Have you tried regular gasoline instead of camper fuel? Mine definately has more ooomph if i use regular gasoline rather than camper fuel.

like i said, the same fuel mix was flying just fine on the other machine that is identical...and was flying on an older set of gasser mechanics... nothing wrong with the fuel.........




Are you using the Z-RC aluminium insulator block?


no.. mine has the stock block with no airfilter/choke box.. exactly the same as the identical machine that fires everytime and runs fine......



Do you have the braided sheilding over the spark plug wire?

yes, but whats your thinking on that one chris?

[Gary Travis]

The sheilded cable has cause hard starting on several I have worked on, Chris ran into this at Chatty. he took the sheilded wire off and replaced with a stock one and problem gone.
Gary

[WayneBrown]

There could be a spark 'leak' or insulation failure between the braided shielding and the boot, remove the braid and try it..
Just for giggles, has the engine backfired on you? It could be the woodruff key between the crank and the flywheel has partially sheared. This sets the ignition timing (primary) and the effect is heightened if the air gap is too large.
While you have it out of the machine, wipe a little baby oil or cooking oil on the spacer, and blot dry on paper a few times. If an edge shows a gap, it's a potential air leak. You can get thicker gaskets from a chainsaw shop for the carb spacer to engine & spacer/carb or cut your own.
I'm still not over the problems we had racing gasser boats yet, All this remains too fresh in my mind.... : :arggg:

[cbergen]

As Gary said, Clay's Spectra was having a hell of a time starting. It would "pop" then quit.

The shielding that you're installing is grounded to the engine. If the spark jumps to this shielding somehow, either through the wire insulation or from the inside the boot to the shielding, your grounding out the spark, which then kills the engine.

We tried a stock coil and wire off of my gasser, and it started right up. We were then able to fly the heli and begin getting it tuned in and setup.

[wingtip]

PROBLEM SOLVED:

turned out that when you remove the red colored boot to slide on the shielding, if you dont get the pin back into the wire just right it wont make good contact with the center conductor... everything runs fine now with the shielding in place... at least till i stripped that new 100 tooth gear :mrgreen:
thanks for all the input.. so if you remove that red cap, be sure the wire is deep into the wire lead and touching the conductor....