Carb problem? Or something else?

hrdman2luv · Aug 14, 2017

31P777-0299-E1.. Carb number, Nikki 697216<< Number stamped on it.

Just changed the headgasket. Cleaned the carb out and changed the needle, bowl gasket (with the O ring). It running better than it did. But still rough. I noticed the oil seemed like it had some gas in it. But I'm fairly sure that was from the carb before the rebuild. I'll change that oil, after I get this problem solved.

Sorry if the sound isn't all that good. That popping is the back firing. Adjusted the valves at 4 & 6.
The headgasket I put on it yesterday, I'm pretty sure was a new one that I had installed on another engine, but took it back off even before that engine was even started.

ILENGINE · Aug 14, 2017

If there is gas in the oil the breather can push the fumes out into the air cleaner, where they are drawn into the intake, and cause a rich running situation.

hrdman2luv · Aug 14, 2017

ILENGINE said:
If there is gas in the oil the breather can push the fumes out into the air cleaner, where they are drawn into the intake, and cause a rich running situation.

The breather? Meaning the PCV valve?

I took the carb apart (4th time now) cleaned it again, put a new spark plug in it. And shot some carb cleaner (sea foam) into the carb after I got it back running again. ( several stready streams (5 seconds each)) This seemed to help at high idle. Not near as much back firing as before. Low idle, on the other hand, was just as bad. readjusted the air screw. But turning it either way, all the way in, out, or in between made no difference as to how it ran. So, I set it 1 1/2 out, and left it there.
One thing, I forgot to take the fuel line off the carb for like an hour. So, before trying to crank it, I took out the spark plug and turned it over. No fuel in the cylinder. Spark plug looked awesome.

Boudreaux In Eunice La. · Aug 14, 2017

How familiar are you with that type of carb. Did you put a new noodle gasket and small o ring in. On those that have been set up for a while with the E gas, welch plugs have to come out and be put back in. I had 1 of those give me fits one time.

I have a gallon of dip I use. Then spray with a can of carb cleaner. You can't hurry up on those Nikki's......

hrdman2luv · Aug 14, 2017

Boudreaux In Eunice La. said:
How familiar are you with that type of carb. Did you put a new noodle gasket and small o ring in. On those that have been set up for a while with the E gas, welch plugs have to come out and be put back in. I had 1 of those give me fits one time.

I have a gallon of dip I use. Then spray with a can of carb cleaner. You can't hurry up on those Nikki's......

I changed both the rubber gaskets. The main one, and the little O ring one. Slid it over the plastic, and not down into the slot.
I did put in a new needle. removed the main jet, cleaned it. Sprayed the emulsion tube with carb cleaner, poke out all the holes. But didn't remove the welch tube.
It wasn't dirty before I did anything to it. The O ring was bad. And the main gasket was a little flattened. But as far as cleaning goes, there wasn't much dirty. All the holes in the emulsion tube were not plugged either.

I was watching a couple of video's earlier, on an engine like this one. The guy put on a new carb, cleans the gas tank, new line, new fuel filter, air filter, spark plug and his still surged. It wasn't back firing like mine is (on low idle). But still surging.

Boudreaux In Eunice La. · Aug 14, 2017

If you feel comfortable about the carb then reset the governor. It could have a small amount of play in it.

hrdman2luv · Aug 14, 2017

Boudreaux In Eunice La. said:
If you feel comfortable about the carb then reset the governor. It could have a small amount of play in it.

Problem solved. I took another carburetor off the other mower, cleaned it out, the SAME EXACT way as I did the first one, new bowl gasket & needle. Installed it, and it runs great. 130lbs of compression. No smoke. Changed the oil again, and no fuel leaking into the oil .

I'm stumped about the first carb though. It's clean as a whistle. All jets are free. The float moves freely, and blocks the hole when the bowl is full. But it still doesn't work right.

cpurvis · Aug 14, 2017

You mentioned Welch plugs. Sometimes they are covering intersecting drilled holes. You cannot be sure you've cleaned the passages without removing the Welch plug.

I ran into this on a Tecumseh snow blower engine. The carb kit came with Welch plugs and I found out why.

Boudreaux In Eunice La. · Aug 14, 2017

Ok great.

Now back to the other carb take it completely apart including the welch plugs. Soak that body in some dip or a ultrasonic cleaner. Those passages still have gunk in them. I think that carb only has one welch plug on the side of the carb....

hrdman2luv · Aug 14, 2017

Boudreaux In Eunice La. said:
Ok great.

Now back to the other carb take it completely apart including the welch plugs. Soak that body in some dip or a ultrasonic cleaner. Those passages still have gunk in them. I think that carb only has one welch plug on the side of the carb....

I've already ordered a new one. So this will be a good opportunity to do just was you suggested. I've a gallon of that carb soak stuff. Berrimans (Not spelled right). I'll soak it for a few hours tomorrow, and see what happens.

A helpful hint for those who dont' have an agitator. If your soaking your parts in a gallon can, you can place the can on top of your outside AC unit (compressor). And every time the AC kicks on, it'll agitate. Works pretty good.

Carb problem? Or something else?

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hrdman2luv

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