General Carb Question...

[carbnclean]

Last summer I watched some youtube videos and fixed some lawn mowers.

Generally what I'd do with a mower, is flush the old gas, get rid of the old fuel line, buy an aftermarket carburetor on Amazon (15-25 dollars). And put the new carb and fuel line on, replace the oil, clean or replace the spark plug, and I would say it would work great about 80% of the time.

For that 20% when it doesn't work.....why? I know that aftermarket carbs are not necessarily bolt n go, but many of them aren't adjustable at all. So with new fuel, fuel line, carburetor, and spark plug, why would a mower still not start? It starts up just fine with a shot of starter fluid, but around 20% of the time with an all new fuel system, it won't start!

Thoughts on why? Or what to do to fix this?

 

[ILENGINE]

Choke not closing completely.

 

[Scrubcadet10]

either what ILENGINE said, i've also ran across a few aftermarket carbs that won't run right or start well, and i give them a quick clean, spray out the main and idle jet etc., and it works like it's supposed to when i put it back on.

 

[carbnclean]

Choke not closing completely.

This is the butterfly valve not closing all the way, just need to adjust it so it does?

 

[Rivets]

I’ve found that about 25% of aftermarket carbs are junk, remember there is a reason they are sold so cheap.

 

[carbnclean]

either what ILENGINE said, i've also ran across a few aftermarket carbs that won't run right or start well, and i give them a quick clean, spray out the main and idle jet etc., and it works like it's supposed to when i put it back on.

Is the choke just the butterfly valve not closing all the way? Just adjust it until it does?

 

[StarTech]

I still haven't why so many carburetors are replaced in the first place as I repair over 99% of them.

What I suspect is that 20% that op says wont start without a shot of fuel are primer systems.

 

[bertsmobile1]

Is the choke just the butterfly valve not closing all the way? Just adjust it until it does?

The one nearest the air filer, assuming hat they have one and are not primer start as this is a generic question
We seem to be getting worse carbs down here as the failure rate would be closer to 50%
So perhaps all of the returns in the USA end up on Evilpay down here.

 

[Scrubcadet10]

I still haven't why so many carburetors are replaced in the first place as I repair over 99% of them.

What I suspect is that 20% that op says wont start without a shot of fuel are primer systems.

well don't you know waiting 2 days or 5 days is less time than 20-30 minutes?

 

[carbnclean]

I still haven't why so many carburetors are replaced in the first place as I repair over 99% of them.

What I suspect is that 20% that op says wont start without a shot of fuel are primer systems.

I am not a mechanic by any means, like I said I just watched some videos, so how would you fix the primer system?