Time estimate to swap carburetor

Leo O'Farrell

Leo O'Farrell

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Jun 25, 2011
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Lakeport, CA
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Leo O'Farrell
Hi,

My 1959 C172 with the 0300A developed a fuel leak from the carb accelerator pump bowl. I thought about it (perhaps getting parts having a new gasket installed, but from my experience with older Ford trucks) obtained an overhauled carb from Aircraft Spruce who had it in stock.

When it arrives, what is the shop estimate for replacement? Is it likely to have the right idle, mixture and other settings correct from the get go?

My plane is uncowled in my hangar, but I'm aware that this is an AP not owner type job. I'd seen a blue stain in the lower cowl that bore investigation and that's how I found the leak.

Thanks.

Leo
 
Around four hours to replace and tune. You can save some by uncowling and cowling it back up for him.
 
Henning,

Is the tuning performed with the motor running? That's how I've seen the carb adjusted in an old F250 Ford, but with the prop turning, just curious....

Leo
 
Leo O'Farrell said:
Henning,

Is the tuning performed with the motor running? That's how I've seen the carb adjusted in an old F250 Ford, but with the prop turning, just curious....

Leo
Click to expand...

Yes, typically you have one man at the controls and one tuning next to the engine. Usually it takes a series of shut down and restarts to get the idle mixture set correctly since one is looking for a 75rpm rise as it dies.
 
Henning said:
Yes, typically you have one man at the controls and one tuning next to the engine. Usually it takes a series of shut down and restarts to get the idle mixture set correctly since one is looking for a 75rpm rise as it dies.
Click to expand...

And you can usually catch it with a quick hand on the mixture control just as it passes peak.

Jim
 
Henning said:
Except that one ****ing fastener that eats an hour all by itself.:rofl:
Click to expand...

THere are only four studs and they are on accessable corners. THe throttle is a single bolt with large area washers on it, the carb heat is another bolt and that &^%*(^^ mixture control is the little poke-you-bloody wire with the setscrew.:yes:

Jim
 
Leo O'Farrell said:
Hi,

My 1959 C172 with the 0300A developed a fuel leak from the carb accelerator pump bowl. Leo
Click to expand...


Actually, if you want to fly it to Grass Valley to change the carb, it is a 10 minute job for the mechanic. If you know enough to find a leak in the accelerator pump, you know enough to pull the carb and change it yourself. My job would be to inspect your work, set the idle mixture, sign your log, and go have a beer with you when you are done flying for the day.

No big deal. The Marvel-Dribbler MA-3SPA is one of the easier carbs to R&R and set.

Jim
 
Only took a couple hours on my Stinson. Of course that's with me de cowling and everything else I could do.
 
weirdjim said:
Actually, if you want to fly it to Grass Valley to change the carb, it is a 10 minute job for the mechanic. If you know enough to find a leak in the accelerator pump, you know enough to pull the carb and change it yourself. My job would be to inspect your work, set the idle mixture, sign your log, and go have a beer with you when you are done flying for the day.

No big deal. The Marvel-Dribbler MA-3SPA is one of the easier carbs to R&R and set.

Jim
Click to expand...
Good to know, and if I do get to Grass Valley will look you up.

Thanks.

Leo
 
Henning said:
Around four hours to replace and tune. You can save some by uncowling and cowling it back up for him.
Click to expand...

His carb does not require removal, it leaks at the accelerator pump bowl, it is a 10 cent gasket and two screws to fix.

then there is no adjustment required.

all you can adjust on a MA3-SPA is the idle speed, and the idle mixture, both can be done by a a single person, simply by running the engine and see what readings you get, then tweaking the appropriate screw.
 
Henning said:
Around four hours to replace and tune. You can save some by uncowling and cowling it back up for him.
Click to expand...
Any one that can't remove and replace a carb on a 0-300 in 2 hours should retire their tool box and advise owners on the inter net.
 
Tom-D said:
Any one that can't remove and replace a carb on a 0-300 in 2 hours should retire their tool box and advise owners on the inter net.
Click to expand...

I don't disagree, but that is not what I would advise someone to expect a bill for, better to be pleasantly surprised than otherwise.
 
Tom-D said:
Any one that can't remove and replace a carb on a 0-300 in 2 hours should retire their tool box and advise owners on the inter net.
Click to expand...

X2

Incompetent or milking you for money otherwise.
 
Tom-D said:
His carb does not require removal, it leaks at the accelerator pump bowl, it is a 10 cent gasket and two screws to fix.

then there is no adjustment required.

all you can adjust on a MA3-SPA is the idle speed, and the idle mixture, both can be done by a a single person, simply by running the engine and see what readings you get, then tweaking the appropriate screw.
Click to expand...

Kool... WB Tom.....

ps,, Ben is sorry for being rude before...:redface::redface::redface:
 
N801BH said:
ps,, Ben is sorry for being rude before.
Click to expand...

No Worries Ben.

Tom took time to reflect upon things, spend time other places doing other things with my time.
 
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