Atomic 4 fuel pump

[mike-atoakville]

Still not sure what I "fixed" to get it going but there were definitely a bunch of bugs in the chrome breather end. So cleaning that, tightening all connections for no sucking air, new fuel pump (but old one proved okay on the work bench) and ultimately pulling hose off right at the carburetor and getting fuel pumping there, seems to have everything okay. Long harbor motor and many starts later, all well. Added a new fuel filter ahead of pump as well but kept the post with glass sight glass.

[Colin A]

Originally Posted by mike-atoakville

Still not sure what I "fixed" to get it going but there were definitely a bunch of bugs in the chrome breather end. So cleaning that, tightening all connections for no sucking air, new fuel pump (but old one proved okay on the work bench) and ultimately pulling hose off right at the carburetor and getting fuel pumping there, seems to have everything okay. Long harbor motor and many starts later, all well. Added a new fuel filter ahead of pump as well but kept the post with glass sight glass.

Yeah small blockages will stop the fuel from going on the A4. We have had clogged vent lines clogged pickup tubes and clogged filters all kill it at one point or another. It pays to go over the system well at the start of each season. I think we ran ours to low one season and sucked some gunk out of the tank and we fought that the whole next season (and eventually just changed the tank and lines)

[TommmD]

Great news! Be aware that if priming is a contributor, running it in secession & for long periods won't confirm it. Sitting a few weeks before restarting would be a good test. Few plan an 'idle' test, but a couple successive cancelled trips can get you there anyway.

[Bill Seal]

Something to think about;
My boss had an A4 that wouldn't run unless a sparkplug (any sparkplug) was pulled. All the "experts" came up with the usual platitudes, which, of course, we had already tried. After several brainstorming sessions at work, (more fun than designing antennas) we figured out it was a plugged muffler, and with a sparkplug plug pulled, the exhaust was coming out of that hole.

[mike-atoakville]

Good reminder to all old Atomic 4 owners. Luckily for me, the plugged exhaust is an old problem that is already fixed on mine. All new iron pipes where needed, new hoses and new stainless steel water muffler. Back pressure can cause all kinds of problems. Not to start another long string of comments, but because the previous owner believed in Marvel Mystery Oil I have kept it up both in gas and crankcase every fill up and every oil change.