Starting engine

[Speedy]

Hi all,

since I had a fuel flow indicator and a carb temp probe installed, I have problems starting my engine (M5 220C). I have started it only three times since the installation, but two times I needed a jump start cable after using up all battery power and the other time it was close to running the battery empty (after pausing several times to give the starter a break). Temperature was around freezing each time. I wonder now -and of course I know it's even more difficult to guess from a distance- if it has to do with the fuel flow device or the carb tem probe or if it was simply the colder weather. I don't remember such problems last winter, though.

The engine gives the impression of not getting enough fuel (or air), but I am never sure whether I primed to much or not enough. Eventually avgas comes out of a little tube on a sheet metal "can" below the engine. I guess that's a sign of having flooded the carburetor or engine at that point.

It used to come alive after one revolution. These times, even if I got it started it quit running again and again.

Any ideas of how to find the problem?

[maules.com]

Unless you have a leak at the probe which is highly unlikely, my guess would be the colder weather combined with your battery getting older and possibly the plugs too.
Check your battery for at least 12.7 volts when you first go to start and again after turning 3 engine revolutions.

[210TC]

This is another case for the digital meter that plugs into the cig liter.
If anyone knows where they can be purchased please post. I have not seen one in a long time.

[Speedy]

Unless you have a leak at the probe which is highly unlikely, my guess would be the colder weather combined with your battery getting older and possibly the plugs too.
Check your battery for at least 12.7 volts when you first go to start and again after turning 3 engine revolutions.

It's not the battery. I was actually surprised how many starting attempts I could get out of it. Even with the jump start cable attached the engine still does not want to start.

We also replaced all plugs at the same time. Can brand new plugs be a problem?

[Speedy]

This is another case for the digital meter that plugs into the cig liter.
If anyone knows where they can be purchased please post. I have not seen one in a long time.

My GPS handheld displays voltage (the GPS battery is empty, so it should be the aircraft battery).

[Kirk]

I've found the plug-in voltmeters at O'Reilly Auto Parts and occasionally Advance Auto Parts for around $10.

I really like the clock I have installed, Davtron M803, which has volts, OAT and clock functions.

Kirk

[Maule 9V]

I have a somewhat related question - at what temp. is preheating an engine a good idea? Operating in SoCal I do not come up against this.

[Rocketman]

I always had problems starting my franklin in cold weather. It didn't matter what age the battery it took a set of jumper cables.
I caught the grass on fire once. Sprayed the engine compartment with a fire extinguisher and boy that was a mucking fess.
The best way I found was to start it spinning with primer in hand. If and when it fired try to keep it running with the primer in stead of pumping the throttle. Once it builds a little heat in the motor it will run. The best way is to use an engine heater.

[a64pilot]

I like to think pre-heat is needed if it's below freezing. It may not really be needed, but what does it hurt?

[Speedy]

Rocketman,

your experience seems to be similar. I will try preheat next time. But preheat was easier as a student pilot with a full-service FBO, where everything was done by the linemen and included in the rent of 35$/hr for the Tomahawk.

Reading the other thread on the Northern Companion preheater, I think I can put my MSR stove to good use in winter.

Thanks,
Martin

[Rocketman]

Also keep in mind this is a 350 cid 6 cyl. motor with what? 10.5/1 compression and trying to turn 50w oil. I found it hard to crank anytime below 40*f. But, once she's alive, man she's alive. I love that motor.

[flyer]

Speedy

Is it possible that something in the installation of your fuel flow meter or carb temp probe may be a cause? You mentioned that the problem occured after these installations.

flyer

[a64pilot]

The carb temp probe could cause a vacuum leak couldn't it? If it is it should be easy to find. I hunt for vacuum leaks with either a piece of vacuum hose used as a stethescope or a can of WD-40. The engine is running of course.

[N6EA]

Speedy,

When I was using the primer during cold starts (around freezing) I was also having trouble. Fuel dripping = too much prime. I now use 3 shots of throttle and I am ready with a couple more as it starts. I use the multi-grade aeroshell during the winter and 50 during the summer. I have found easier starts with the multi-grade. As others have pointed out, the Franklin is a bit of a hot rod and at 10.5 to 1 she can be a load for your starting system but it sounds as if that isn't the problem. Try to vary the air/fuel prime by starting with just a couple of throttle shots and work up from there. When you get the correct mix, it'll fire but I think the compression of these jewels makes it finicky. Just my .02

[Speedy]

Thanks for all the tips. I think I have solved this problem (and can and will go on to discover new problems, that means).

What helped is that I now use the heating element that the previous owner installed on the bottom of the oil sump. I had not used it previously and was uneasy about using it before, because I feared it could pose a fire hazard overnight in an unattended hangar with 10 other airplanes parked next to mine. Anyone ever heard of a fire due to a heating element in the engine compartment? Anyway, I controlled it for a couple of hours and decided it was safe to use.

The other tip that seems to work well with my engine is to leave the primer out when cranking the engine and using the primer instead of the throttle after the engine fired to keep it running.

Speedy