canardlover

Just bought a used DLA 32cc gasser and will bench-run it soon. Found one problem though - the spark plug cap will NOT snap on and stay in place as I want it to. It falls off at the slightest touch. Therefore I fabricated a piano wire spring to secure it in place(see pics) The plug cap metal shield does indeed touch the plug body but I assume that is intended or at least allowed..??!!
Please comment on this before I start up the engine and possibly destroy something in the process....! THANK YOU..!

A. J. Clark

The cap is not down far enough. Push down on it and twist back and forth until it goes down around the hex part of the plug. If it still doesn't hold good on the plug you can put a small hose clamp around the base after you get it seated down.

tedsander

You may have to do some research/calling. See if you can contact the manufacturer of the ignition system (maybe RcExl) or the engine manufacturer.
They make caps to fit specific brands of plugs. I had a Champion plug in my engine, and I fought with RF noise problems for a very long time. Turned out the cap was made for an NKG plug (per RcExl). It fit, and no more RF noise!
Although the plugs were of the exact same type, it was very noticeable in side-by-side how differently constructed they were.

canardlover

BINGO..!!!..thanks a lot A.J...!!! Twisted and pushed as advised and that did it..!!
tedsander: my ignition system is FTL CDI model A-01, will look around for spares here in Sweden first. Spark plugs are available so I will check what is most suitable for me.
Thanks both of you for quick and fruitful replies, wish me luck when I start it up, the engine has been shelved for quite a few years.

While I have you "on the line" guys: I ponder whether I should skip the regular tap gasoline as it contains 10%+ ethanol these days and go for alkylate fuel instead..?!?!..whaddayathink..?!?!?

LLRCFlyer

TedSander is correct in stating if the cap is not all the way down on the plug, it will create RF noise sufficient to overpower most 2.4 gHz receivers. If not fully seated, there will be two sparks, one across the gap from the cap and top end of the sparkplug and another spark at the electrode. No, you will not hurt the ignition system by grounding the cap to the engine. It is designed to work that way. The high tension lead carries the charge to the spark plug center post and the cap (touching the spark plug hex wrenching portion) and braided outer sheathing completes the circuit back to the ignition module. You will most likely notice there is no separate ground wire back to the ignition module, although some older modules used a plain rubber high tension lead and had a braided cable that had to be clamped onto the spark plug's body bolt. The quickest way to fry the ignition module is to energize the module and turn the prop without a sparkplug fully seated in the cap.

LLRCFlyer

You stated your engine is several years old. Most older carburetors use diaphragm and gasket materials that are not compatible with ethanol... so... you will need to either find a source for 100% gasoline (preferred) or verify that your carburetor is compatible for up to 10% ethanol fuel. Even if it is compatible, ethanol fuel goes bad rather quickly as the ethanol tries to absorb moisture from the air.

tedsander

Found this manual - but unsure if your engine predates the 32cc they cover. DLA%20Operating%20Manual%20Current.pdf

They warn about ethanol OVER 10%, so presumably you will be fine. I'm running some other brands that use Walbro carbs that are over 20 years old, that have no issues with 10%. Here in the US, ethanol has been in use in some areas for a very long time now (since 1997 in my state), so things have to be really old to be incompatible. But there are still many that don't trust it, so are always looking for a place that sells "pure" gas. The warning about moisture is valid though - so keep what you have for airplane use fairly fresh (ie - one season, not stored over the winter).