Another carb thread.

hrdman2luv

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Briggs V twin 407577-2083-E1. Was running rough, so I did a little tune up on it, plugs, oil change, new air filter. But, it ran just the same, so I adjusted the valves and cleaned the carb out. (697722 stamped on top of carb). It's the one that has the "noodle gasket" between the bowl and the carb.

I noticed before I pulled the carb, that it seem to run better with the choke pulled. Now, after cleaning it out, and reinstalling it, it's even worse. When you choke it, it runs great. But when you release the choke, it does what it would normally do when you pulled the choke.

I double checked my choke linkage and the other. They're right. I sprayed WD 40 all over it and the intake (when they mount to the head and the carb, and no change in the way it runs. With the exception of spraying on their with the choke released, because it dies quick.

Any advice will be appreciated.
 

cpurvis

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If an engine needs help from the choke to run, the mixture is too lean.

Why?

Either too much air or not enough fuel.
 
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When you take apart one of those Nikki carbs with the noodle gasket the main jet nozzle has a lot of holes in it all those should be routed out with wire and spraaaayed well. There is a welch plug to that covers the idle port and that has to come out sometimes.

Did the main jet fall out of the plastic housing are did you take it out to clean that well ??
 

hrdman2luv

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When you take apart one of those Nikki carbs with the noodle gasket the main jet nozzle has a lot of holes in it all those should be routed out with wire and spraaaayed well. There is a welch plug to that covers the idle port and that has to come out sometimes.

Did the main jet fall out of the plastic housing are did you take it out to clean that well ??

All those little holes got wired out good. And the main jet was still in.

As far as the welsh plug goes, I didn't take it out. But have found many times that if the carb is clean, from what you can see (like in the bowl and other visible places on the inside of the carb) then behind the welsh plug is usually clean as well. Although, I admit, there could be something behind it. I wired the air holes leading into the welsh plug (thin brass wire)
 

hrdman2luv

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If an engine needs help from the choke to run, the mixture is too lean.

Why?

Either too much air or not enough fuel.

IIRC, (and I may be thinking about a different carb) but that little hole on the black plastic that holds the air filter, down in there, there's a big hole for the air. And another smaller hole. Isn't fuel supposed to come out of the smaller hole, when it's running? I'm not sure how or why, since the fuel line lead directly into the side of the carb itself. Because there's no fuel at all coming out of it.

Or am I thinking about a different carb?
 

cpurvis

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IIRC, (and I may be thinking about a different carb) but that little hole on the black plastic that holds the air filter, down in there, there's a big hole for the air. And another smaller hole. Isn't fuel supposed to come out of the smaller hole, when it's running? I'm not sure how or why, since the fuel line lead directly into the side of the carb itself. Because there's no fuel at all coming out of it.

Or am I thinking about a different carb?

You'll have to post a picture for me to visualize what you're talking about.

I'm just guessing, but if air bypassing the filter is what you're talking about, that doesn't fall into the category of 'too much air.' It's just unfiltered air. It doesn't change the mixture; it changes the life of your engine.
 

hrdman2luv

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You'll have to post a picture for me to visualize what you're talking about.

I'm just guessing, but if air bypassing the filter is what you're talking about, that doesn't fall into the category of 'too much air.' It's just unfiltered air. It doesn't change the mixture; it changes the life of your engine.

The black plastic cup that starts at the air filter. It's part of the air filter housing. That leads down and curves into the carburetor. On some of the, above the big hole that goes into the carb, there's two small (pencil size) holes that also go into the carb. This one, only has one.

http://outdoorpowerinfo.com/repairs/images/briggs_intek_v-twin/_breather_tube.JPG


I've got the carb soaking in carb cleaner. I noticed the noodle gasket wasn't fitting right. And was a little flat on one side. Plus, one of the holes close to the main jet, I could stick a wire in it. But not very far. I'm guessing that's clogged up. Hopefully the berrymans will loosen it up enough to get a wire further down in it.
 

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hrdman2luv

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Sometimes they're just dead and want to stay dead. I suppose.

I soaked it for two days. Cleaned everything out, again. The passage ways I thought were passages ways, were not. They're vent holes, that don't go anywhere. So, I put a new noodle gasket in it. And a new needle. And now, the ONLY way it would stay running, was with starting fluid. I thought the fuel pump might have gone bad, so I took fuel line loose, turned it over and it came out. Not very strong, so I checked the vaccume tube that connects to the bottom of it, and sure enough, it had a crack in it. So, I put a new one on it and thought, BY GOLLY, I got'r now.

Still nothing.

So I yanked one off a junk mower, cleaned what I could get to, without taking it all apart (intake housing and float bowl). It started right up, and runs pretty good.
It's got a little miss in it.
Compression tested 165 on the left. About 100 on the right. May have a blown head gasket.
 

zman111666

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Or could be valves that aren't seating well, and need lapping. But to get to that, it's gonna get the head gasket in the process... :smile:
 
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