irishfield
Registered User
Penetanguishene, Ontario Canada
Case history:
Last winter, unless very well preheated, my O-320-C2A (B2A derated to 150hp) wouldn't start at all if below freezing. It then almost left me stranded twice after ice fishing ... and thankfully started just as the battery was about to go dead. New Odyssey 980 so I'd cranked it for a long long time. Was starting to think the speed it cranks with the new battery vs the old Gill didn't let the impulse coupling do it's job and once the battery started to get low it would fire.
This summer, it fired up like a champ every time. Always within a turn and never an issue.
I flew home in September, took the airplane off amphibs and returned it back to my wheel skis and it's sat in the hangar ever since with the fuel shut off. Other than a movement around the yard here where I noticed I had mag differential at 1700 rpm... 70 drop or so on left.. 120 on right.
Finally got around to setting my mags the other day... left was firing at 27 BTDC and right was at 21. They are both set damn near on 25 now.
Without preheat, after setting the mags, I gave it two shots of prime and she fired RIGHT up. Then died... I gave it two shots of prime, it fired right back up and died... then I realized I still had the fuel shut off. Opened the fuel valve, fired her up again and she ran like a dream.
With Jen getting a green light for now, I thought I'd treat myself to some ski flying. Went to go flying yesterday... crank.. crank.. crank.. crank.. and fuel pouring on the floor out of the air box after the failed start attempt. Farted around with it for a bit with more floor washing. Took the carb off... popped the bowl off, cleaned every orifice, made sure the float sits level... needle seats okay and put it all back together.
Tried to start it this morning... same deal today, with no start and fuel pouring out. I should have tried starting with the mixture pulled lean I guess. Waiting for it to dry out and heat up right now.
I disabled the primer line, to be certain the fuel wasn't being sucked through it.
Carb does not leak when sitting with fuel on, so I know the needle / seat is working. It only pours fuel out after cranking for start.
Questions:
Could it be the high speed cranking of the Odyssey battery keeping my impulse coupling from working?
Could the high speed cranking be sucking fuel out into the carb throat and then when no start it just pours back down and out?
Is it possible my fuel level is too high in the bowl and that is why it gets sucked out??
Can I put a 10-5135 that I have here in O/H condition on in place of my 10-3678-32 without issue? I'm fairly certain it was a Cessna 172 carb for 150 HP.
THANKS!
Wayne
Last winter, unless very well preheated, my O-320-C2A (B2A derated to 150hp) wouldn't start at all if below freezing. It then almost left me stranded twice after ice fishing ... and thankfully started just as the battery was about to go dead. New Odyssey 980 so I'd cranked it for a long long time. Was starting to think the speed it cranks with the new battery vs the old Gill didn't let the impulse coupling do it's job and once the battery started to get low it would fire.
This summer, it fired up like a champ every time. Always within a turn and never an issue.
I flew home in September, took the airplane off amphibs and returned it back to my wheel skis and it's sat in the hangar ever since with the fuel shut off. Other than a movement around the yard here where I noticed I had mag differential at 1700 rpm... 70 drop or so on left.. 120 on right.
Finally got around to setting my mags the other day... left was firing at 27 BTDC and right was at 21. They are both set damn near on 25 now.
Without preheat, after setting the mags, I gave it two shots of prime and she fired RIGHT up. Then died... I gave it two shots of prime, it fired right back up and died... then I realized I still had the fuel shut off. Opened the fuel valve, fired her up again and she ran like a dream.
With Jen getting a green light for now, I thought I'd treat myself to some ski flying. Went to go flying yesterday... crank.. crank.. crank.. crank.. and fuel pouring on the floor out of the air box after the failed start attempt. Farted around with it for a bit with more floor washing. Took the carb off... popped the bowl off, cleaned every orifice, made sure the float sits level... needle seats okay and put it all back together.
Tried to start it this morning... same deal today, with no start and fuel pouring out. I should have tried starting with the mixture pulled lean I guess. Waiting for it to dry out and heat up right now.
I disabled the primer line, to be certain the fuel wasn't being sucked through it.
Carb does not leak when sitting with fuel on, so I know the needle / seat is working. It only pours fuel out after cranking for start.
Questions:
Could it be the high speed cranking of the Odyssey battery keeping my impulse coupling from working?
Could the high speed cranking be sucking fuel out into the carb throat and then when no start it just pours back down and out?
Is it possible my fuel level is too high in the bowl and that is why it gets sucked out??
Can I put a 10-5135 that I have here in O/H condition on in place of my 10-3678-32 without issue? I'm fairly certain it was a Cessna 172 carb for 150 HP.
THANKS!
Wayne