# 5 hp B&S won't idle



## Sanman (Feb 4, 2014)

I have a 5hp B&S that I can't get to idle.
model# 135292
type# 0141 01
code# 93032407

I bought it with an old go kart that was not in running condition. I have cleaned the carb, twice, and replaced the diaphragm and gaskets to the motor and tank. Fresh oil, gas, and new spark plug.

The motor runs strong, but it will not idle. The carb is a pulsa jet and being that the low speed idle jet is not accessible for me to physically poke a wire through, I'm guessing it is plugged. I have even removed the small welch plug and tried to force air through the jet with no apparent success.

Anyone have any ideas for me to try?


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## Sir Thomas (Dec 7, 2013)

Sanman said:


> I have a 5hp B&S that I can't get to idle.
> model# 135292
> type# 0141 01
> code# 93032407
> ...


30yearTech will probably correct me on this. Have you tried checking the governor lever. I believe they are adjustable. Unless this is a van type governor there is a nut where the governor lever is attached to the governor shaft that goes into the motor.


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## Sanman (Feb 4, 2014)

Sir Thomas said:


> 30yearTech will probably correct me on this. Have you tried checking the governor lever. I believe they are adjustable. Unless this is a van type governor there is a nut where the governor lever is attached to the governor shaft that goes into the motor.


The governor lever is detached along with all the corresponding linkage. I did not open the crank case to actually see if the internal parts of the governor were removed, nor have I watched the little post that comes out of the case while the engine was running to see if it moves indicating whether the internal parts were removed or not.

Currently I have the idle screw all the way in, causing the throttle to be slightly open. Enough gas comes through to keep the engine running for a little bit, but then dies. Adjusting the idle mixture needle does nothing. Right now it's at 1 1/2 turns out, but I've tried it everywhere and the engine does not respond at all, even when I screw it all the way in... no change. 

So I'm guessing the only fuel I'm getting through the carb is from the main jet because I have the idle screw turned in so far. To be of any use on the go kart, the engine needs to idle slower. What to do?


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## Sir Thomas (Dec 7, 2013)

Sanman said:


> The governor lever is detached along with all the corresponding linkage. I did not open the crank case to actually see if the internal parts of the governor were removed, nor have I watched the little post that comes out of the case while the engine was running to see if it moves indicating whether the internal parts were removed or not.
> 
> Currently I have the idle screw all the way in, causing the throttle to be slightly open. Enough gas comes through to keep the engine running for a little bit, but then dies. Adjusting the idle mixture needle does nothing. Right now it's at 1 1/2 turns out, but I've tried it everywhere and the engine does not respond at all, even when I screw it all the way in... no change.
> 
> So I'm guessing the only fuel I'm getting through the carb is from the main jet because I have the idle screw turned in so far. To be of any use on the go kart, the engine needs to idle slower. What to do?


I have rebuilt a pulsa jet carb on a Briggs and Stratton engine. Have you taken the idle jet screw out completely, removed the seat and/or replaced it or the screw? If you adjust the idle screw and it does nothing then it sounds to me like there is something going on with the jet. If you haven't replaced the jet I would think that it is the problem. Look at the tip of the jet screw. If over tightened it can damage the tip. Also there should be a rubber "O" ring in there. 
The jet determines, if I'm not badly mistaken, the amount of the fuel mixing with the oxygen. When too much fuel is mixing with the oxygen with the throttle plate open, it's running to fast but when you close the throttle plate then it floods. That's my take for what it is worth.


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## Sanman (Feb 4, 2014)

Sir Thomas said:


> I have rebuilt a pulsa jet carb on a Briggs and Stratton engine. Have you taken the idle jet screw out completely, removed the seat and/or replaced it or the screw? If you adjust the idle screw and it does nothing then it sounds to me like there is something going on with the jet. If you haven't replaced the jet I would think that it is the problem. Look at the tip of the jet screw. If over tightened it can damage the tip. Also there should be a rubber "O" ring in there.
> The jet determines, if I'm not badly mistaken, the amount of the fuel mixing with the oxygen. When too much fuel is mixing with the oxygen with the throttle plate open, it's running to fast but when you close the throttle plate then it floods. That's my take for what it is worth.


Great suggestion! :thumbsup:
I just removed the idle mixture needle and there is no "O" ring.
I'm assuming it would be black. I have a really bright headlight that I used to see down in the hole and everything looks clean, but no "O" ring! 
I'll go get one tomorrow and hopefully we'll be in business.
Crossing my fingers!


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## Sir Thomas (Dec 7, 2013)

Sanman said:


> Great suggestion! :thumbsup:
> I just removed the idle mixture needle and there is no "O" ring.
> I'm assuming it would be black. I have a really bright headlight that I used to see down in the hole and everything looks clean, but no "O" ring!
> I'll go get one tomorrow and hopefully we'll be in business.
> Crossing my fingers!


There should be jet kit. It's not a good idea to just replace parts of the jets assembly. The seat has a slot which lets you screw it out. Once you get it out flush the jet port out good. The proper order is the jet seat, then the spring, washer and "O" ring goes on the jet screw. When you screw them in, screw it just snug, not tight then back it up 1 1/2 turns. See frame 10 on the attached file.
Briggs and Stratton Pulsa Jet Carbs


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## Sanman (Feb 4, 2014)

Sir Thomas said:


> There should be jet kit. It's not a good idea to just replace parts of the jets assembly. The seat has a slot which lets you screw it out. Once you get it out flush the jet port out good. The proper order is the jet seat, then the spring, washer and "O" ring goes on the jet screw. When you screw them in, screw it just snug, not tight then back it up 1 1/2 turns. See frame 10 on the attached file.
> "http;//www,compgoparts,com/Pages/156/BriggsCarburetors,aspx" Briggs and Stratton Pulsa Jet Carbs


I took another look and there is no seat down in the hole either.
I can clearly see to the back to the hole that opens up into the carb throat. 
So, a new kit including a needle, seat, washer and "O" ring. 
Also, excellent website. That really helps!


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## Sanman (Feb 4, 2014)

Upon further investigation, I don't think getting a new seat is going to be an option for me. I've attached a diagram of the carb that I have. When you look at the Idle needle, there is no "O" ring, washer, nor is there a seat to remove from the carb. All you have is the idle mix hole the needle screws into.

I've looked at some diagrams of other very similar pulsa jet carbs and they have a much larger idle mix opening on the carb, and also show the seat that screws in. I'm guessing my version is one that does not allow changing the seat. 

Here's a website that has some great views of the carb.
http://outdoorpowerinfo.com/repairs/briggs_pulsa-jet_horiz_fixed.asp

Thoughts?


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## Sir Thomas (Dec 7, 2013)

Sanman said:


> I took another look and there is no seat down in the hole either.
> I can clearly see to the back to the hole that opens up into the carb throat.
> So, a new kit including a needle, seat, washer and "O" ring.
> Also, excellent website. That really helps!


Wow, no wonder you can't idle it down. Let me know. I wonder why someone would take that out.


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## Sanman (Feb 4, 2014)

*Success!!*

Ok, I called the small engine shop and picked their brains and did what they suggested as a last resort because you very easily could ruin your carb. The following is what I learned.

1. My pulsa jet carb has no removable seat, nor O ring for the idle mix. The needle screw just screws in and flushes up with the interior of the carb. So, I guess if anything destroys that seat down inside I'm out of luck... new carb.

2. They were not surprised to hear the motor wouldn't idle. It's common for the low speed circuit to get clogged for this carb. The gas that is used for both the low and high circuits comes in through the main jet. In my carb it is a fixed jet (not removable). In the picture I posted it is in the blue square. The gas continues straight up into the carb for the high speed circuit. For the low speed circuit which travels parallel up to the idle mix needle, the gas has to pass through a small hole in the sidewall. It's that hole in the sidewall that gets clogged.

3. The easiest way to access and clean that hole in the sidewall is to remove a ball plug on the opposite side of the main jet. Removing that plug is not easy. It's not supposed to come out. If it does your engine will immediately flood.

So, I took my drill and slowly worked around one half of the ball plug. It took a while because I was being careful, but I finally removed enough material that I could pick the ball out with a dental pick. I was then able to use a wire and cleaner to clean out the entryway to the idle circuit. I removed the idle mix needle and used compressed air to make sure the passage was clear. Then I put the ball back in the hole and sealed it in with solder.

The engine idles great now. Looking forward to never doing that again!


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## Sir Thomas (Dec 7, 2013)

Sanman said:


> Ok, I called the small engine shop and picked their brains and did what they suggested as a last resort because you very easily could ruin your carb. The following is what I learned.
> 
> 1. My pulsa jet carb has no removable seat, nor O ring for the idle mix. The needle screw just screws in and flushes up with the interior of the carb. So, I guess if anything destroys that seat down inside I'm out of luck... new carb.
> 
> ...


Definitely a different pulsa jet than that which is on my Briggs and Stratton. It must be modified.


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## 30yearTech (Sep 14, 2006)

Sir Thomas said:


> Definitely a different pulsa jet than that which is on my Briggs and Stratton. It must be modified.


Not modified, just a different type of pulsa jet carburetor (newer). That is why model numbers are so important when discussing issues on equipment. This way we all know what we are dealing with and can give more specific suggestions.


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## Sir Thomas (Dec 7, 2013)

30yearTech said:


> Not modified, just a different type of pulsa jet carburetor (newer). That is why model numbers are so important when discussing issues on equipment. This way we all know what we are dealing with and can give more specific suggestions.


This is the one I rebuilt.







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Not sure why it is rotated.


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## 30yearTech (Sep 14, 2006)

Yes, this is a pretty old set up, this carburetor does not have the low speed circuit pictured on the new carburetor.


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## Sir Thomas (Dec 7, 2013)

30yearTech said:


> Yes, this is a pretty old set up, this carburetor does not have the low speed circuit pictured on the new carburetor.


Still purrs like a kitten. The guy that brought it to me gave me a dare. If I fix it I could keep it. Guess what...I fixed it...I kept it.


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## 30yearTech (Sep 14, 2006)

Pretty good deal :thumbsup:


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## Sir Thomas (Dec 7, 2013)

30yearTech said:


> Pretty good deal :thumbsup:


On Briggs and Stratton motors you can go back a long ways for parts but the tiller...well that's another story. It's a Tillman and they have been out of busness for a long time. A metal bar that links the forward and reverse lever to the belts was missing. I had to have a friend of my get a metal bar and drill a bunch of holes in it. Combining guess work on that and finding the right belts for the forward drive and reverse drive on the tines...oh boy...but I did it.


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