could I be running on three and not even know it?

[snowbeard]

if I pull plug #1 off to test the spark, it makes absolutely no difference to how the engine runs. the same holds true for plug #2. if I pull 3 or 4, the engine dies immediately. does anyone have any ideas??

problems --> surging, almost like it's losing spark and getting it right back rough running

here are some of my thoughts, and why it's not the reason...

plugs ---> good spark on all four, just removed caps from #1 and #2
and cut half an inch off and reseated them.

coils ---> test to proper ohms both ways

kill switch ---> cleaned and dielectric greased

ignition signal --> the cover could be less than watertight?

gas to carbs? --> 1 white (lean?)
2 black (rich)
3 light tan(good)
4 light tan (good)

petcock -->appears to be leaking thru diaphram (see plug 2 rich)


she did get rained on on friday, but it was beginning to have these problems thursday right after jumping it off a running car...??

[dtkid]

While this may be obvious: I always spit on my fingers and touch the exhaust to tell if any cylinder is running less than the others (after ample time for the pipes to get good and hot). Even though they may all be somewhat hot, the rate at which the spit vaporizes will be obvious if one cylinder is running lean (very hot) or not at all (only warm).

You probably didn't need me to tell you that... but there it is.

Good Luck: David

[redliner1973]

Alot of times cylinders will drop out only at idle, once off, tehy start to fire, hence giving you the symptoms you have. If the idle mix is not set right this could happen, as soon as you get off the idle mixture, it starts firing and you dont feel like your only running on 2 cylinders. The colours of your #1, #2 plugs seem to confirm this, one is too lean at idle, not enough fuel to support combustion, one is too rich, drowning out the plug.

[snowbeard]

well, I have seen the #1 cyclinder not fire before, as in never warm up, but that was three years ago and it seemed to have gotten it's act together and was doing well.

now what it does is sputter and surge on acceleration... could it still just be gas delivery?? maybe I should plug the vacuum line and set it to prime for testing...? I'll check the float bowls to make sure I'm getting gas to all of them...

it's been doing very well for awhile, but it's been leading up to this for a month or so, now it just finally got really bad...

[Jethro]

I always spit on my fingers and touch the exhaust to tell if any cylinder is running less than the others (after ample time for the pipes to get good and hot).

I do this too. After 20 or 30 seconds from dead cold, I touch right where the header first bends. Sizzle = good.

[NotSoFast]

Ditto on the pipe-feely-thingy.

[redliner1973]

Sounds like a carb-clean job is in your future. And while there, check/replace as needed your Mainfold "O" Rings. That sputter is prolly the #1 starving for fuel...you will burn it up if you continue using it like that.

[snowbeard]

I guess so, it's gonna take some time to get free enough to do that. drat, driving the cage for a while again I suppose...

thanks for all the help!!

[DaveDanger]

I do the same thing for exhaust stack testing, but I like my fingerprints so I use a plastic screwdriver handle. Just flip it over backwards and touch the base of the handle to the pipe. If it's scorching hot it'll slide like buttter on a hot skillet, if it's cold or cooler, it'll feel like it's sticking. You quickly develop a feel for the relative temps. With this method, you can test the pipe temp at most any time, right after start, or after a long ride, or anywhere in between.

[JohnnyV]

Yikes save your screwdrivers and fingers from burnin hot exhaust pipes and try a spray bottle with some water.

[DaveDanger]

johnnyv, the spray bottle of water (or even spit) works well also, I just seem to get a better read from the screwdriver handle. I've been using the same set of Snap-On screwdrivers for close to 30 years and have yet to replace one due to melting. It's just a quick touch and off. Not going to hold it there till the blade shank grows hot