Engine Start Issue

[Rogerck]

Our CTSW wouldn't start after sitting idle for a couple of weeks. Battery power and engine turnover were fine, but not even a sputter.  Checked gravity fuel flow on carb side of fuel pump and flow was fine.  The problem was finally resolved by draining fuel from the float bowls and fuel hoses at the gascolator, and draining several gallons of fuel from tanks at gascolator.   After this process, and with fresh fuel added to the tanks, engine started right up.  I've had this same situation once before with same "fix".   It seems that fuel gets funcky when sitting in lines/float bowls for extended time and replacing fuel with fresh solves the problem.   Not sure this really makes sense, but have no other explanation. 

 

Any ideas?

 

Roger Kuhn

[FlyingMonkey]

Dumb question, but did you use the choke when trying to start?  Engine turning on start without catching is exactly what mine does if I forget the choke on first flight of the day.

[Anticept]

Age of fuel?

 

Was it sitting outside?

[Rogerck]

I used choke to start as normally done and fuel in float bowls was about 1 month old and never stored outside. 

[Rogerck]

I had another hard engine start today after only one week form flying the CTSW before.

 

Some facts:

- The engine turned over like a champ. No battery problem here.

- Engine ran fine during last flight and run up. No roughness or issues whatsoever. Engine and starting has been fine until today.

- Fuel is always fresh

- Other than components required for rubber change, nothing has been done to carbs. There are no fuel stains or wet spots on carbs. TT 650 hours.

- No smell of fuel which might indicate flooding.

- Disconnected fuel line between fuel pump and carbs. Flow was positive from gravity feed.

 

When trying to start today, used normal procedure, throttle all back, some choke. Turned it over several times, not even a sputter. Tried turning again after 5 minutes, finally caught - at half throttle position. Once started, no roughness or issues with engine. Mag run ups were normal.

 

Any ideas?

 

Roger Kuhn

[FastEddieB]

Seems to be an epidemic!

[Doug G.]

Fuel pressure good?

[Rogerck]

Roger,

 

What do the starting modules do differently during the start up phase that isn't being done during continued running (firing plugs)? It also seems strange that both units would not function. Today's hard starting was with a cool engine, maybe 78 degrees OAT. Not sure what you are suggesting with an ice pack. Lay it on the modules for 1/2 hour before starting?

 

Roger Kuhn

[Mike Koerner]

Make sure you shut off the fuel valve (above the ignition key) after each flight. If not, some fuel may leak past one of the float valves, fill the bowl and dripple into the carburetor throat resulting in a hard start next time out.

Mike Koerner

[Runtoeat]

Mike K. might have a good thought on using the fuel shut off to see if the float needle(s) might be leaking and flooding the engine.  It would be worth a try for Roger Kuhn.

 

Roger Lee, don't mean to hijack Roger Kuhn's thread but same subject here.  My 2006 seems to be giving me a slow turn on the 1st turn of prop when starting.  After the 1st turn of the prop, the engine then cranks OK and starts OK.  Could the one or both modules be going to 26 BTDC momentarily and then to 4 BTDC after the first couple of turns of the engine?  Wondering if this might be an indication of start of module failure?

 

 

[Rogerck]

Roger,

 

If one of the starting modules is bad, can the cable for each be disconnected one at a time and then try starting? From what you've said, a bad module may prevent a good one from functioning.

 

Roger Kuhn