Primer working?
Cheers, David
RV-6A O-360
Lately it seems my old slick mag technique is not working so great.
I usually just 'prime' with the acc pump while running the starter.
Then check to make sure the accelerator pump in the carb (Marvel Schebler?) is working. If it's working correctly, you should be able to 1st fill the float bowl with the boost pump, then after 5 or 6 full strokes with the throttle, you should see fuel dripping out of the cowl. (Not saying to prime that much; just a quick/dirty way to check acc pump operation.)
I'm assuming you normally run the boost pump to fill the bowl prior to 1st start, right? I'm also assuming that you have a weep hole in the airbox to let excess fuel (and any water that might enter the intake while sitting outside) drain out.
edit: I'm not sure how valuable hand-turning the prop is, to prime the engine. I usually just 'prime' with the acc pump while running the starter.
Since you quoted me, were you actually addressing me? If so, please re-read what I wrote. You're preaching to the choir on pumping the throttle prior to engine start. I only said to do it as a troubleshooting method, to be sure that the acc pump is actually working. They do fail, and if his isn't working, he isn't getting the 'priming' action you'd expect.Sorry, in the interest of safety, I just have to comment. WIth an updraft carb, there is no value in pumping the throttle with the engine not cranking - you just pump fuel into the air box. One backfire and you have an engine fire!
BTW - the carb bowl should still be full from previous engine run, unless you have a heck of a leak. No need to "fill it" with the boost pump. Pump on, leave it on, and you'll have a pressurized system. If not - you have a leak.
Pump the throttle WITH THE ENGINE CRANKING and you'll get a good prime. There is this hard to kill myth that pumping the throttle before cranking doeas something - and it did, with a downdraft carb on a V-8 in your old car. Not with a Lycoming!
My start with dual P-Mags and a Carb is: P-Mags hot, start cranking, two pumps (three if its cold) and the engine is running. Easy.
Paul
Since you quoted me, were you actually addressing me? If so, please re-read what I wrote. You're preaching to the choir on pumping the throttle prior to engine start. I only said to do it as a troubleshooting method, to be sure that the acc pump is actually working. They do fail, and if his isn't working, he isn't getting the 'priming' action you'd expect.
As to the rest, remember, we're talking about troubleshooting an engine that's hard to start. Assuming that everything is as it should be just isn't a valid assumption, or it wouldn't be hard to start. We don't know whether there's a slow bowl leak, what kind of fuel he's running, how often it runs, etc etc.
Charlie