Hard start on older B&S
 

I was gifted an older walk-behind trimmer powered by a B&S Quantum engine. It wouldn't turn over initially, so I replaced the carburetor and now it will turn over and run but it takes MANY pulls to get it to turn over. I'm talking by the time your arm is worn out, it finally turns over and runs. Once it's running, it goes like a champ. If I shut it off, it will fire right back up again in 1-3 pulls. It's just hard to start after it sits for any period of time, even overnight.

What would be a good path to go down to get this thing starting in a reasonable amount of pulls where I don't hafta wear my arm out every time I want to use the thing?

hmm... I've worked on a lot of old Briggs and Stratton engines. Usually when I have an issue like this, its caused by a lack of fuel. Pulling it over enough times eventually gets it to start pulling gas through the carb properly and run.

Is this an upright (horizontal crankshaft) engine or a vertical crankshaft engine?

Ultimately pictures of the engine would help a lot as there are many variations of these engines, and it would be better to know specifically what variation you have :bigthink:

If it has an air filter housing like this one it's probably not priming. Remove the filter and press the primer bulb, you should see gas squirt into the carb. Several times when I have removed the air filter housing to clean carbs and have not used a new carb/housing gasket it has not sealed well enough to allow the primer to work. See this video
https://www.youtube.com/watch?v=NFMGKUT7BnA
Cannon

I'll see if I can get some pics.

When I press the primer bulb, I can feel fuel in there, but i guess that doesn't necessarily mean it's squirting into the carb. I did use the new gaskets with the new carb as well...

Here are the pics of the engine and the trimmer model. I can't find any model markings on the engine itself, other than it being a B&S Quantum 5HP

If you are pulling the rope and it is not turning over, you have a problem with your recoil assembly. Check that as it is prolly your problem.
If you are using a confusing description/term of "turning over" and it is turning over but not starting or at least attempting to start, then that is an entirely different situation.
Are you using the prime bulb? those engines need 5-6 plunges of the bulb or more.
if you are doing that,and it is still difficult to start,then inspect the bulb/line to see if it is ruptured/ damaged or not functining properly.
report back.

I'm sorry George, I forgot you are specific about those terms. For me, "turning over" means the engine starts running under it's own power without me pulling the cord.

I haven't tried priming it more than 6-8 times since I don't want to flood it, but if it's not getting enough fuel to start then obviously it's not flooding...

I think I figured out the problem. The new carb doesn't have a hole for the primer, so it's not even priming! See the photos the primer hole just goes into an empty nub on the carb.

I guess it's my own fault for not paying more attention when buying cheap carbs off the internet. While it fits the engine, it's not made for a primer bulb...

Edit: looks like you got it, I was too late! I would still take a look at that fuel line just to be sure though. And give that engine a good cleaning too!

Yeah, it definitely needs a bath lol. Maybe I'll try to clean out the old carb and use it so I don't wear arm out. But at least now I know