# 1980 Pulsa-jet Carb



## NITROJC (Jan 12, 2008)

Hello people, I have this Pesky 2 pick-up tube, adjustable needle setting, Briggs 5hp. pulsa-jet carb.
The Questions I have may, or may not be Technical, but I need the answers. I understand that when the needle is closed this shuts off the fuel, and will kill the engine. When open to 1 1/2 turns, this is the apx. good running setting. Usually between closed, and 1.5 open ... fuel is on the Lean side. Open at 1.5 to opening more would Richen the fuel mixture. 
What I want to know is .... What happens inside the carb (fuel / air flow) if when the needle is closed the engine continues to run ? What effect does this have on fuel, power, and engine behavior ?
Secondly, When this needle adj. makes no difference/change in rpm's at any setting .... What effect does 
this have on Engine Performance ? A quick response to my questions will be Greatly Appreciated.
Have a Great Day, Thanks, Nitrojc.


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## Maytag (Dec 10, 2007)

http://www.compgoparts.com/TechnicalResources/BriggsCarburetors.asp

Not sure I can answer your questions but check out the link and step through the images. Be sure to look REAL close for the thin black line that represents the fuel flow in each image. Also I think frame 10 may offer some help as far as the paragraph that goes with the 10th image.

>Maytag


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## NITROJC (Jan 12, 2008)

*Needle Valve*

Hi Maytag, Thanks for the functional Illustration, but I already have that one. One thing for certain is that the fuel pump is working, because the fuel flow can not be shut off. Hopefully, someone out there does know, because this would answer a lot of other unanswered questions that need answers.
In the past, one fella known as "30 year tech," has been quite helpful, Amongst the rest of you !
Maytag, Thank-you for trying to help. Sincerely, Nitrojc.


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## dehrhardt (Apr 1, 2009)

Nitro,

You want to check the mixture adjustment needle to make sure it it isn't grooved. If the needle is near the base of the carb, near the tank, it is an idle adjustment only. If it is higher, near the centerline of the carburetor bore, it is both idle and high speed adjusting. If it is grooved or damaged in any other way, you need to replace it.

Also, if the fuel pump is on the bottom of the carb, where it attaches to the tank, you could be having issues with the carb sucking fuel from the pump vacuum chamber. Even if the pump is the same as shown in maytag's link, (on the side of the carb), you could have a small hole in the diaphragm and be sucking in fuel.

Hope this helps


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## XXX#40 (May 12, 2007)

That carb has a diaphram in it, if you adjust the needle and nothing is happening, the needle needs replaced, or could be that the jet is damaged from someone screwing it in too far


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## NITROJC (Jan 12, 2008)

*" I Fully Agree "*

GUYS, I agree with both of You, but that's not what I am asking.

The needle is grooved, and is in the centerline of carb, controlling both High, and Low speed systems. So what Effect does a "grooved needle have on Engine running?"
Also, If there is a small hole in the fuel pump diaphram causing it to suck in fuel, What Effect does this have on Engine running ?

IN BOTH Problems above, Would the engine - Lack Power / Bog down, and stumble / run Rich, or Lean / Only run with Full Choke on.

Please try to be specific with your answers. Thank-You, Nitrojc.


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## dehrhardt (Apr 1, 2009)

The effect of having a grooved needle is that you wont be able to adjust the mixture. If you think it's running fine then I suppose you could leave it alone. If you're sucking fuel through the vacuum area of the fuel pump it would tend to make it run rich.


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## NITROJC (Jan 12, 2008)

*Questions*



dehrhardt said:


> The effect of having a grooved needle is that you wont be able to adjust the mixture. If you think it's running fine then I suppose you could leave it alone. If you're sucking fuel through the vacuum area of the fuel pump it would tend to make it run rich.


 OK. I also would agree with the above. Now most of the time the engine is lacking in power, and must be 7/8 choked in order to run, Indicating Very rich ! So what passageway is restricted or plugged? From closed to wide open the needle makes no difference, so its running Rich, Right. Yet the spark plug is tan in color indicating the proper A/F ratio, Right. If it truely was rich the plug would be black, and you'd see black smoke out of the exhaust, Right. My Best Guess is that Either there is a fuel restriction, or one Hell of an Air Leak, Or a combo of both Perhaps. Which is the most probable cause for these carbs, what do you usually find?
 Secondly, What are the Signs of a "small hole in the diaphram," How would that effect the way the engine runs, Other than Richer ? I Do Know that any engine running Either Too Rich, or Too Lean ... WILL LOSE POWER ! I know this from Engine Dyno when I ran power runs controlling fuel, and spark.
If I could have Pin-pointed the Problem, I would have No-reason to ask these Questions of you Folks. It would be Fixed. Thanks, Nitrojc.


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## dehrhardt (Apr 1, 2009)

Nitro,

If you have to choke it, it's running lean. I don't know what you've done or tried to do, but you should at least replace the screw, so it will be adjustable again. I would also replace the diaphragm. Both of these are inexpensive. I don't know how long the engine sat or whether it had stale fuel in it, but if the gas varnished you will have to clean the carb also as there is likely a restriction somewhere in the carb, or a clogged screen. Here is a link for the manual in PDF format:
http://www.mymowerparts.com/pdf/Bri... Single Cylinder L-Head BRIGGS & STRATTON.pdf

It is also possible that you have an air leak. Check the condition of the gasket between the carb and the block and make sure all is tight. Since you didn't provide model and spec nos. for the engine, it is worth noting that Briggs has produced many varieties of the pulsa-jet and the ones used on vertical shaft engines are generally different than those for horizontal shaft engines. That is why I provided the link. Read carefully and let me know how you make out.


Dave


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## Maytag (Dec 10, 2007)

Hey NitroJC,
No problem.
I have a thought. Incase we're not seeing the forest for the trees in the way........Could it be (if I have this right) you have a stuck ball valve in the takeup tube that goes into the fuel tank? 
I think some of them have a small ball that acts as a one way valve that can rust in place. If it's stuck half way open that might be your restriction point. Or (help me out professionals) is this a moot point because of the smaller tank in a tank used like a carb float? 

Just tossing a thought out there. I have no idea how relavent (or accurate) it might be.

Good Luck.
>Maytag


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## dehrhardt (Apr 1, 2009)

Check ball's are only in the vacu-jet (single tube) carbs.


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## NITROJC (Jan 12, 2008)

*Carb -cut-away*

Hello guys, Sorry - My mistake, I should have posted the numbers, so you would know which carb I have.

Here they are: 130292 ... 1061 02 ... 80090806 

Maytag, I think that's a different carb that has the small ball in pick-up.

Dave, I believe all that you have mentioned has been tried, that's why this carb mystery is so frustrating. What I really need is a cut inhalf carb to explore, and search out passageways to Better understand the flow of gas inside the carb. I have No clue how many small Internal passageways there are to plug-up. Would you happen to know, and where there located ?
Any chance someone might have a cut-away sectional Pic, or picture ?
I would rather try to pin point a restriction, since the soaking, and replacing the pump diaphram have made No difference. Thanks, Nitrojc.


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## dehrhardt (Apr 1, 2009)

I don't have a cutaway of the carb. I couldn't find the spec no you provided, but I believe that there is a removable seat for the mixture screw. The passages behind the seat would have to be clear. Also all passages to the fuel pump. The fuel pickup tube should be removed for cleaning, then replaced. I neglected to mention before that if the tank isn't venting properly through the cap you will have fuel starvation problems. I trust that since you have already separated the carb from the tank, that you also have made sure the tank was clean. I'm not sure how much I can help you beyond this point and invite others to add anything I might have missed. Another option might be to get a used carb from one of the other members, a local shop or from ebay.

Good luck, and let us know how it goes.
Dave


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## XXX#40 (May 12, 2007)

Some of the new gaskets are too thin and cause the pickup tube to hit the bottom of the tank, replace the diaphram, jet and needle and add a second gasket between the tank and carb.
Be sure to clean the carb with carb cleaner, making sure the metering holes are clean, over time gas can make the metering holes larger than they need be, and then its time to sell it to a kart racers so it can be converted to run on methanol
the numbers you gave 130292 are for a 5hp L head, my guess is that the carb has a #2 on it some where


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## indypower (Apr 8, 2009)

For some reason, this guy won't listen. He has 3 pages of replies on DIY and won't try anything sugessted. DIY has told him all the same things that have been said here. The guys at DIY have become so digusted with him, they will no longer answer his posts. I would advise everyone here to ignore his posts as if he had done what he was told, his problem would have been solved by now. He also failed to mention that he used RTV sealer on the carb gaskets.


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## NITROJC (Jan 12, 2008)

INDY, WHAT HAVE YOU BEEN SMOKING, OR DRINKING ?? I DON'T APPRECIATE THE SLAM ! Its Unfounded ! Furthermore your comprehension reading skills are lacking.

Back to the subject: XXX#40 What did you mean when you said, "When the holes become to large it's time to convert it to methanol." What effect do the enlarge holes play/have with the carb ? Does this have anything to do with Fuel A/F Ratios ? Please follow this Up. Thank-You, Nitrojc.


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## NITROJC (Jan 12, 2008)

*The Truth Shall Set You Free.*

" TO WHOM IT MAY CONCERN:" I suggest for those who believe in Indypower to check - in on the " Village Garden Web forum." Go to the Index left column, Scroll down to Tractors, and click on it. This should bring up " Lawn & Garden Tractor " forum. Scroll down to the bottom, then go to page 50, and click on it ... Look for " 8 hp Briggs generator," by Nitrojc. Please read All the postings. I AM REALLY TIRED OF SOME PEOPLE SAYING THAT I DON'T FOLLOW THROUGH WITH THINGS SUGGESTED ! 
INDYPOWER - You, yourself should be the first to check me out, and See for Yourself ... The fool you really are !
Hopefully, This will put this harassment to rest.... For Good ! 
Thanks for Believing in me. Nitrojc.


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## NITROJC (Jan 12, 2008)

*Mr. Wizzard*



indypower said:


> For some reason, this guy won't listen. He has 3 pages of replies on DIY and won't try anything sugessted. DIY has told him all the same things that have been said here. The guys at DIY have become so digusted with him, they will no longer answer his posts. I would advise everyone here to ignore his posts as if he had done what he was told, his problem would have been solved by now. He also failed to mention that he used RTV sealer on the carb gaskets.


 Indypower, You are the one that has now opened this door for rebuttal. 
I have again proof/re-read all the posts, and may I say again, you need to follow the train-of-thought. Had you read beyond your conclusion about the red rtv, you would know that the "PROBLEM HAS EXISTED FOR 2 YRS!" / INCONSISTENT ENGINE PERFORMANCE, Before, and After the use of rtv.
The Conclusion Here is that RTV IS NOT a Factor.
Secondly, With all the pages of postings, Why didn't You (with your Infinite Wisdom) Suggest a Patent diagram; After All your the expert ?? For that matter Cheese should have thought of that when he mentioned all the hidden passageways. " DAH ... IT'S A NO BRAINER !" Everybody who read the postings, knew from my questions that I was trying to pin-point the problem. So, it stands to reason a "Patent Drawing/s" Probably will/would be the Ticket. Just, Maybe I have Expected too much out of the Pro's. Regards, Nitrojc.


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## geogrubb (Jul 28, 2006)

Nitro;
I have to agree with Indypower, you have 36 posts/replies at DIY, 37 posts/replies at Village, 23 post/replies at Perr and 17 post here at hobbytalk, plus whatever other forums you have posted to, I suggest you try each suggestion from each site one at a time and when you get it fixed you will have "PINPOINTED" the problem. Have a good one. Geo


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## NITROJC (Jan 12, 2008)

*" Just Like A Politician "*

:freak: GEOGRUBB, You should run for Congress in Washington, the spin you've put on the postings .... Unbelieveable ! Tell me Geo, Were the postings all for the same problem, or did you simply combine them All-into-one ? As you know, I have Several Different small engines that I have posted, in the past on All of the Forums. Again, You should run for Office.

Tell me there Fella, Have you taken the time to read about the " 8hp Briggs generator," by nitrojc ?? I Guess not, you prefer to Slam people rather than do something Constructive. I would Pray that I don't become Senile, as you must have become ... in my retirement years. Later, Nitrojc.


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## geogrubb (Jul 28, 2006)

Sir, you have problems far beyond being senile. May you awaken at some point and realize the dream you are living is not a dream and the posts you are posting are reality, as I have stated before, I have no interest in reading your BS. I post to the forum in an attempt to help, you post in an attempt to intimidate, sorry that doesn't work with me. You have been banned from other forums and as you continue your BS you will be banned from this one as well. OH and, Have a good one. Geo


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## NITROJC (Jan 12, 2008)

*Intimidated With The Truth*

:freak: Grubb, You are intimadated by the truth, and at your age should realize that "The Truth Shall Set You Free." By prolonging/delaying reading the post "8hp briggs generator," You will Never be Free from your Guilt !
I would have preferred to send you a PM. or E-mail, but most Illiterate people are also Degenerate, Not capable of Private communication.
OH, and Have a Great Day.


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## Griffworks (Jun 24, 2002)

Alright, you guys need to calm down and re-read the TOS, particularly about respecting the opinions of others and not insulting other members, regardless if they "started it" or not. Remember two things about these forums: 

1) Hank wants to keep them Family Friendly; 

B) If you don't have anything nice to say, don't say anything at all; and 

iii) It's just a hobby, fellas. 

I'm locking this thread before anyone ends up posting something which ends up getting them a Time Out. 

.


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