Over the last year, after a flight, my CARBURETED 470R has been difficult to start after sitting for 10-45mins. A flooded start procedure will generally work but it takes a lot of cranking. The issue nearly got stuck at a remote strip for a few days.

Since then I've replaced the carb thinking it could be a float issue. The mags, plugs and harness are all new within 18months.

When cold, or over an hour after flying, it starts on the 2nd or 3rd blade.

I called Joe and Aircraft Cylinders in Greely for input. Sounds like he's having the exact same problem with his new O470L in a 182 and has been giving it a shot of primer to get it going after being shut down.

Anyone else running an O-470 having similar issues or better yet solved a similar issue?

Have you tried opening the throttle quite a lot to give it air and a lean mixture? Once you learn how much, it will be easier the next time.
Be ready to close the throttle when it starts as it will be at considerable power. I flew some tired engines that were harder to start this way with the compression low.

I had this exact problem several years ago, it was due to the mags. If you have checked all else is there anyone in the area that can bench test them

I know you said you have recent mag's but I had the same problem with a Lycoming and it was because the coil's were going bad. When they were hot from sitting a little while they didn't work.

No problems hot starting my IO-520, I'd recommend getting fuel injection.

I would suspect mags epically if they are slicks. Check the timing (internal mag timing and engine timing). What is your normal hot start procedure? How does it differ from a cold start? Is the starter spinning the prop at the same speed on both? How many blades does it take to start when cold? I would suspect carb last especially if it starts fine cold.
DENNY

I agree this is probably the mags - ages ago on my 470-R I ran into this as well and after chasing it forever found out it was the magnetos.

Also another issue can be if the primer nozzles are bad.

Heat can make the coils cranky. Have you tried a cruise power mag check? That will show a weak mag pretty obviously. Don't do it with a nervous flyer on board...

I agree on the mags. Especially if they are a Kelly rebuild or new Kelly slick mag. Their points suck and we’ve had numerous issues with the points throwing the timing off after short TIS. Coils also get cranky when hot and are hard to check because you can’t get them hot while bench testing.