Primarily for general aviation discussion, but other aviation topics are also welcome.
We used to have similar problems with our Continental 0-200 and, some years ago, one member did have a fire. Since then we always follow the same procedure and it always starts instantly.

Blower fire for 30 minutes (Winter only)
Boost pump on until it stops clicking.
6 pumps of the throttle
Turn prop through 8 blades
3 pumps of the throttle
Throttle set and start.

This procedure worked on our clapped out engine as well as it does on our new one.
We've experienced difficulties starting engines with carbs at our club on and off over the years. In the beginning, only some pilots have problems but over time more or less everyone is affected. Every time, investigations have shown problems with the magnetos. When replaced, problems disappear. You should have it checked out.

Following the POH rather than local lore should of course be the first course of action. But AIUI that's what the OP does. (We fly C172 and PA28 with both 160 and 180 hp Lycomings, and to my ears eight primings seem excessive. Two for cold starts in the summer up to three-four in the winter is what I'm used to. But whatever the Robin POH says should be right.)
Here's an example of a POH that no one I knew followed as it was indeed a bit bonkers. I mean, would you pull through 4 blades with the throttle fully open, mixture full rich and no one inside, praying the mags really were off and there isnt a fault?

It resulted in a replacement of that section of the pups POH


On my Pup, "rosie" which doesnt have a primer (or a key starter, Hatz :wink: ), I seem reliably to be able to start her every time on first/second press of the starter button, in all conditions*. I start on the left Mag.
Im pretty cautious of over priming, so I dont over prime on the throttle prior to start, two or three primes and I dont sit there with the fuel pump running for ages faffing about. I do pump the throttle on turning the engine.

I have some sympathy with Matthew as I have flown his aircraft "Bob" and had difficulty starting him when cold. Ive not seen the fuel running out but what I do is if he doesnt start after a few attempts, well I usually give it a break and have a cuppa and come back after 10/15 min and he starts.

Im pretty sure that its low temperatures that cause the fuel not to vaporise and thus make it more difficult to start a Lycoming in the winter.

Ridders wrote:Here's an example of a POH that no one I knew followed as it was indeed a bit bonkers.


It is errors like that which make me worry about the requirement (during PPL training*) to use the manufacturer's approved checklist. Every aircraft I fly (eight aircraft, seven types) has some sort of error in the "approved" POH. Most of the errors aren't as serious as the example above, for example only checking the vacuum gauge after closing the throttle, or switching off the avionics after shutting down the engine, but they should (IMO) still be corrected.

* Private flying, including self-fly hire, allows the use of customised (/corrected) checklists.