And we're back.... I am unsure if I should just continue this thread or start a new one as I kind of feel like I am starting from square one again. So went out today for the first shake down after trying to find the water leak... To my joy the bilge remained dry... though there was a drip or two down the transom at the end of the hour ride or so. But that is another thread. What happened here was identical in a way to the original issue I was having before the rebuild.
So I'm out running and shoot up to my old marina, about half an hour run. I zip around the river up there absolutely beating the **** out of the thing. Running great and everything. Run back south at a faster than normal clip, about 3800 RPM. Go down the river and decide to open it up one more time. Now I normally kiss the rev limiter anyway and I got a pop or two out of it during this pull. normal for the limiter so I back down to 4000 RPM. Coming back up the river I get a pretty good pop out of the engine at that rpm. Back down to 3000 and head toward the ramp. get a few pops at 3k. Dump the throttle to idle and it shakes a little and is running rough. get to the ramp and shut it off.
Fast forward home. On the trailer it audibly sounds like I have a cylinder occasionally not hitting. sitting with the throttle just off idle (1k rpm) it all of a sudden jumps up 300 RPM and clears up. Idle sounds normal now too. WTF is going on.
So, my list of things to check: (I have work this weekend so it'll be a bit.)
- Dump the fuel filter and check for debris and replace (It's due)
- Pull the plugs
- Compression test
- check the cap and rotor (new last fall along with plugs and wires)
Future tests:
- Try and duplicate problem with fuel pressure gauge in line and see if it's a delivery issue. (again)
- Leak down test
- I'd check valve lash but it's a net lash 4.3 so you just torque and go
- Smoke test intake?
One observation I made, there is a tiny bit of oil on the valve cover. Appears to be around breather. I don't believe it is the culprit but perhaps an underlying issue.
Anything else I should test/check? I'll add I rebuilt the carb just before this all started. I don't know that it's a carb issue though as you'd think it would happen almost immediately.
And I have to ask... Ignition systems usually work or don't. That's been my experience with electronics. But if a thunderbolt V system is starting to go out... could this be the behavior you'd see? It doesn't seem right but you never know.
