At 12:05 AM 6/14/2002 -0400, you wrote:
>I think primer bulbs are unsafe.  I like to use a push-pull type primer AND
>connect a choke cable.  I will prime the engine with the push-pull to get it
>to fire and run long enough to get the fuel pump going, and I'll keep it
>running with the choke.  Works for me.
>
>Tom Olenik
>Olenik Aviation

I cannot echo Tom's advice strongly enough.  I blew up a 503 from a leaky squeeze bulb in the fuel line.  I bought the bulb new a month before that, and probably ran it all of 10 hours.  This was a "high quality marine" bulb.  It deed seem much sturdier and higher quality than most.

The rubber had cracks that were only visible when bending the bulb, but were sucking air.  This air leaned me out and caused a seizure.

They are also prone to get stopped up from their check valves getting jammed or escaping their cage.  They also contribute bits of rubber to the fuel flow.  

I absolutely won't have one on any of my planes.  Period.  They are junk that belong on boats.

If you insist on having one, at least have a bypass hose so a plugged bulb won't shut you down.  Also put a filter after the bulb to catch the crap.  Also put a filter before the bulb to keep crap out of the check valves.

Also, they don't help start a cranky engine.  All the do is fill the bowl.  Also, some folks think they're going to use that little squeezy as a backup when their fuel pump dies over the forest.  Forget that nonsense...fly the plane and land it.


I, too, use a plunger manifold primer.  It makes any cantankerous Rotax start like a Toyota.  I highly recommend them.  You can run just the primer, without choke, but you end up chasing the RPM's until the engine settles down.  If your lines don't stay primed between weekends, you'll get really good keeping it running on the primer until the lines and bowl fills.  Of course, if you're seeing that, you need to rebuild your fuel pump, float valve, or find the air leaks in your system.

I like using the primer in concert with the choke (enrichening circuit).  Set the choke, two squirts, pull the rope once or twice, pull the choke off a few seconds later and you're in business.  This is the system I recommend.



-Dave Hempy