carb to engine matchup

looknlearn · Jan 14, 2011

I have a 9 hp Briggs and Stratton horizontal shaft cast iron 23D or 23C gas engine which has a carb that has given me problems. I have replaced float the needles and jets, and the gaskets to no avail. I found a new carb that is listed on ebay and says fits a 10-12 hp briggs horizontal shaft engine. Will it work. I asked the ebay lister and he wasn't 100% sure so I'd thought I'd ask here.
Thoughts?

PILOON · Jan 14, 2011

I have done a fair number of carb swaps quite successfully.

First is the engine CC's (or HP)
Next is the mounting flanges.
If throat size is same (gasket) and CC's are close it generally will work fairly well other than throttle linkage which can generally be worked around with cable placement changes.
Some engines might have the intake mounting bolts at an angle which complicates adaptation. (like some briggs)

Good luck!

looknlearn · Jan 15, 2011

I don't ever recalling finding the engine listed in CC's. It is a 1965 briggs I think and it is listed as 9 hp. The carb looks exactly the same except the way the air filter mounts. I don't have a measurement, but from the looks, I'll give it a go unless someone knows it won't work.
Thanks

ArtMech · Jan 18, 2011

Actually the carb should accord to the engine's capacity to provide the proportion of air/petrol intake 15:1. If that proportion would be ignored (the carb will provide higher fuel amount to the cylinder while the intake air amount will remain the same), engine may throw unburnt petrol away, which may lead to black smoke, high fuel consumption, lack of nominal power and some other long term consequences, like losing compression, engine oil consumption.
I'd better seach for original carb which accords with Your engine, or would try to fix a concrete issue on a present fuel supply system.
That's my thought

looknlearn · Jan 18, 2011

It seems like since it is a gas engine it would only draw in as much fuel/air mixture as it needs to run. If the mixture is too rich it would not run right.

Right??

ArtMech · Jan 18, 2011

looknlearn said:
It seems like since it is a gas engine it would only draw in as much fuel/air mixture as it needs to run. If the mixture is too rich it would not run right.

Right??

Correct Tucker, just I would add "...as it needs to run properly". Too rich and too weak mixtures both are not good. And many components play the role, like dimensions of air inlet, air filter, jets'...
By the way, both carbs may look and even be identical except the jets. I'd look for a possibility to compare them somehow before purchase. Some specs maybe are available? No?