I would see if I could borrow a good mag switch and try that. Kevin1
--- In [email protected], Hartmut Beil <hb...@...> wrote: > > > Ed. > > > Excellent analysis. > > > > Running lean can be a cause for that kin of trouble. > > Under lean condition, the effects get worse when only one spark plug is > firing in a cylinder. > > > > The quick test is to pull carburetor heat and see if the symptoms smooth out > or disappear. > > > > A lean condition can be caused by the carburetor itself but also any intake > leak along the way to the cylinders. > > > > > > Hartmut > > > > > > > > > > > > > > > To: laspr...@...; [email protected] > From: e...@... > Date: Mon, 9 Nov 2009 06:17:13 -0600 > Subject: RE: [ercoupe-tech] intermittently bad run-ups > > > > > > > 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 > > > > > > _________________________________________________________________ > Windows Live: Keep your friends up to date with what you do online. > 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_1:092010 >
