[Spridgets] Troubleshooting..

[Dave Yealy]

Pull one plug at a time and do a compression test on each cylinder. 
My Morris did the same as your Sprite and the problem was two valve 
seats dropped out of cylinders 1 and 4.

Dave



At 10:44 AM 3/17/2013, you wrote:
>Last year before I buttoned up the Sprite for winter I took it for a usual
>weekly ride.
>
>About 4 miles from home I was waiting to get around a tree service crew.
>As I passed them the car began to stumble an run really rough.  It felt like
>it was running
>on two cyclinders along with a pinging type of sound.
>
>I limped home and parked the car for winter.  I figured that perhaps
>something was wrong
>with my home brewed MSD box.  I would deal with it in the Spring.
>
>So today I'm out troubleshooting the thing.  I started by making a little
>harness that allows
>me to swap out the MSD box.  I figured this is a good thing to have anyway.
>But the MSD box
>was not the issue.  In fact spark is not the issue. Plenty of spark on every
>cylinder even without
>the msd box.
>
>It seemed like at idle, I could pull cylinders 1 & 2 spark plug boots and
>not see an appreciable
>drop in rpms. So I thought maybe something was wrong with the front SU carb.
>
>I opened and drained it's float and removed the bell.  I then took canned
>air and reverse blew
>through the main jet to make sure the tube was not clogged.
>
>That was'nt it.
>
>Now I'm worried, so I pull the valve cover to make sure none of the rocker
>adjuster had'nt worked
>loose.  No problem there...
>
>So now I'm thinking either valves or head gasket.  But the failure was
>sudden.  Has to be head gasket.