Linda.
To eliminate bad spark plugs, i would just replace all of them. A new set of plugs is like day and night. Aircraft Spruce is selling them at a reasonable price : http://www.aircraftspruce.com/catalog/eppages/champsprkplugs.php REM40E is what we normally use. I am using REM37BY by now, a plug that due to its design will not foul that easily. So far I barely can feel a magneto drop on the upper plugs with these spark plugs. Hartmut CC: [email protected] To: [email protected] From: [email protected] Date: Mon, 9 Nov 2009 22:24:51 -0800 Subject: Re: [ercoupe-tech] intermittently bad run-ups Ed, I'm sorry for the apparent miscommunication. It seems the only time that *both* mags dropped badly on run-up was when the problem first surfaced, and on that occasion it repeated 3 times consistently. Immediately after that, Jess cleaned the 4 sparkplugs he could get at easily at my tie-down, and once he did, apparently on *his* run-up attempts since then, only 1 mag had a bad drop and rough running -- and that only intermittently. But I will still run your ideas by him (and the others kindly contributed by Tech List posts). I haven't heard anything since Friday when he was going to go check the spark plug wiring and the mag timing. Thank you! Linda On Nov 9, 2009, at 4:17 AM, Ed Burkhead wrote: > > Linda, > > I am NOT any kind of mechanic and must not play one on the Internet. > However, I'm a tech support geek whose business is to solve technical > problems. So, I'll stick my ignorant oar into the puddle. > > You say the mag drop happens on BOTH mags whenever it happens. > But, the > event is intermittent. This pattern has been repeatedly demonstrated. > > To me, this means: > 1. If it is the ignition switch or mag related, then the problem > is in > the ground wire or the ignition switch's ground which are the only > common elements. > > 2. You said the big mag drop is coincident with dieseling. Doesn't > dieseling come from something in the cylinder(s) being too hot causing > ignition in the absence of a spark? What causes hot spots in the > engine? Running way too lean? Thus, I would look for something that > could cause excessive leanness and is common to both mags. I'd be > looking at the carburetor and, in particular, > a. the float, > b. the mixture control section (looking for clogs and to clean it > completely (I once had a fiber air filter shed fibers which clogged > the > air passage on the Stromberg carb causing excessive leanness)) > c. fuel flow issues (which I'd check by finding PERFECTLY clean > pavement and doing a high power runup to see if it's the same) -- > possible causes include fuel hose collapsing internally, sloshing > compound, clogged screen in the gascolator, > d. if it's running lean, then the carb heat should richen the mixture > causing a mag rise > e. ?other?. > > Next, I'd look at other common elements such as the air filter. > > I can't see the individual mags or P-leads or spark plugs causing this > drop on BOTH mags at the same time, intermittently. The only common > element is the grounding wire from the ignition switch and the switch > itself. BUT, I'd expect this kind of electrical failure to do > something > radically different from a 200 rpm mag drop. > > Just my non-mechanic, technical analysis thoughts, for what it's > worth. > > Ed > > Ed Burkhead > http://edburkhead.com/Ercoupe/index.htm > ed -at- edbur???khead.XXX change -at- to @, remove ??? and > change > XXX to com > > > _________________________________________________________________ Keep your friends updated—even when you’re not signed in. http://www.microsoft.com/middleeast/windows/windowslive/see-it-in-action/social-network-basics.aspx?ocid=PID23461::T:WLMTAGL:ON:WL:en-xm:SI_SB_5:092010
