Surging motor on NEW carb!?

l008com said:
Also I did put the O ring in there between the carb and the block. It made no difference. I checked the valve spacing, it seemed pretty good. One was a tiny bit loose, I tightened it up, no change.
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You check the valve lash clearance and you tightened one up? Did I understand that correctly? What did you measure for valve clearance? How did you adjust the clearance?
 
I went with .005" for both. And how? I loosened the bolt, adjusted the gap, and tightened it back down again. Is that what you're asking?
 
l008com said:
I'm not sure why it was dying with the air filter on, and running much better with the air filter off, when the filter itself is super clean and spotless. Very strange. Its kinda like someone sprayed clear coat on the filter so it looks good but doesn't let air pass.
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I've seen OLD clean looking paper filters cause running issues. Install a new fresh filter and she runs like a top. Guessing paper gets old and doesn't flow like a new one?? Probably was an aftermarket unconfirmed but definitely old.
 
l008com said:
It runs, but poorly. I push on the spring to open the throttle (not WOT i don't think) and it runs much better. Then I let go and it runs like poop again.
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THIS engine is made to run at 3600rpm. Soon as you pull the rope until you shut it off.

Carb does NOT have a pilot circuit to assist proper running when you incorrectly idle down the engine revs.

Set it at 3600rpm as we all heard it ran better and leave it alone.
 
Anyone asked about the engine numbers yet?

Is this a Briggs autochoke model?

Definitely a Quantum style nbpt100 mentioned about.
 
How are you suggesting I "set it at 3600rpm"? In the video I did it by pushing on the return spring on the governor. Someone suggested bending the linkage a little bit, I may try that and see how it goes. The numbers are posted in a previous post. This model has a primer and no choke.

120602 0131 E1 990820 FA
 
You have either a throttle/governor spring or a choke/throttle cable controlling the speed. First should be like a metal tab. Second is a lever. Post up pictures of what you are working on.
 
Pretty sure this is a fixed speed engine. As in 3600rpm. Not meant to idle down.

Briggs, Kroller, Honda and Kawasaki all state run at max revs for max cooling and lubrication. Speaking of max engine life slash durabillity.
 
Pictures of what exactly? I'm not really sure what you're saying or suggesting here.

Also to all who suggest drilling the jet, I swapped with the jet from the old carb and the behavior is unchanged. And I know that jet doesn't need to be drilled out, and I know its clean.
 
So the more I research this online, the more it really does not look like a fuel issue, the more it looks like either some kind of governor issue or an ignition issue.

Assuming that is true, and ignoring the carb for now, what are some ways I can test and diagnose this, other than buying parts. One idea I was told was to put the spark plug tester on there and run it and see if the intensity of the spark in the tester corresponds to the surging of the motor, and that that can indicate a bad coil. I like that and I'll have to try that.

It still surges somewhat when I pull on the governor spring so that suggests the spring isn't the problem. I want to try firmly holding the throttle open more and seeing what happens. Its the governor causing the problem or reacting to the problem.

Aside from the external spring, I'm not sure what I'd even be looking for for a "bad" governor. I assume I'd have to remove the motor and crack it open, which I have done before on a different machine but I really don't want to do now on this machine. I really want the problem to just be the ignition coil so I could just bolt a new one on and be done :D
 
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