Briggs carb adustment

[creia]

1972 Briggs 5HP Model 130202 with brand new OEM Briggs carb
This is the model with the "Pulsa-Jet" carb that bolts on top of the fuel tank. There is only one adjustment screw for the fuel mixture.
The repair manual states that the starting/default position for the screw is 1.5 turns out to get it to start and run- which I have always done. Then, you adjust in or out as needed to get it to run the best.
On most engines I have ever done this ends up being from 1-1.5 turns out. On this particular carb the best setting is (only) 1/2 turn out! Any more than that and it sputters black smoke when you go to open the throttle quickly. It starts, idles, and runs best at the 1/2 turn out setting.
Should I be concerned?
Any idea why it runs so well at only 1/2 turn out?
Am I worrying too much and should just let it go and move on?
Thank you,
Michael

[RoyM]

Let the engine do the talking! If it runs well at 1-1/2 turns leave it alone and be happy.

[creia]

Let the engine do the talking! If it runs well at 1-1/2 turns leave it alone and be happy.

Hello Roy,
Certainly a good point and I am inclined to agree with you. Out of all the engines I have done I have had a few carbs that ran best at only 3/4 turn out, however this one at (only) 1/2 turn out was a first.
Michael

[bgsengine]

1972 Briggs 5HP Model 130202 with brand new OEM Briggs carb
This is the model with the "Pulsa-Jet" carb that bolts on top of the fuel tank. There is only one adjustment screw for the fuel mixture.
The repair manual states that the starting/default position for the screw is 1.5 turns out to get it to start and run- which I have always done. Then, you adjust in or out as needed to get it to run the best.
On most engines I have ever done this ends up being from 1-1.5 turns out. On this particular carb the best setting is (only) 1/2 turn out! Any more than that and it sputters black smoke when you go to open the throttle quickly. It starts, idles, and runs best at the 1/2 turn out setting.
Should I be concerned?
Any idea why it runs so well at only 1/2 turn out?
Am I worrying too much and should just let it go and move on?
Thank you,
Michael

every now and they you find one of those - Generally it can mean several things - perhaps the carb was jetted for a different application, or mis-jetted at the factory , potentially a casting defect allowing extra fuel in somewhere it should not go, (one of those permanent ball plugs for example) Can also have a incorrect seat/jet (the brass part, IF THERE IS ONE) or an improperly formed needle (or an extra thread that positions needle wrong) In any case, if you are able to adjust it so it runs properly, then you're all good. I have had engines with all the aforementioned issues where I could NOT adjust the problem out until I replaced or repaired the issue (Most were "somebody else tried to fix it" induced problems however, not on new carbs that I can recall) But if it starts and runs good, I would have no concerns about how many turns in or out are needed to get proper mixture adjustment, long as it runs consistently and properly wherever it is needed to do so, it isn't a concern.

[creia]

OK- Thank you all. You have put my mind at ease and I'll stop being a worry-wort.
Michael

[Merkava_4]

1972 Briggs 5HP Model 130202 with brand new OEM Briggs carb

I see there's three different parts lists for that model depending on the type number. They're showing two different mixture needle part numbers. 23433 & 231533. The one with needle 231533 has no needle seat listed. The other two with needle 23433 have needle seats. I think we need more numbers. I think we need the type number and code number. The part number for the carburetor you bought would also be helpful.

[SUKI]

Actually there is close to one hundred different type numbers list on the Power Portal.

Personally I given up on different sites asking constantly for complete equipment numbers. Posters on some site have nearly bitten my head off when I insisted on having the needed info. They it is just a dang mower or engine. What they don't realize is that there is a lot of differences between equipment configs.

[creia]

1972 Briggs 5HP Model 130202 with brand new OEM Briggs carb

I see there's three different parts lists for that model depending on the type number. They're showing two different mixture needle part numbers. 23433 & 231533. The one with needle 231533 has no needle seat listed. The other two with needle 23433 have needle seats. I think we need more numbers. I think we need the type number and code number. The part number for the carburetor you bought would also be helpful.

M- 130202
T- 0135-04
C- 7202227

The carb was Briggs # 299437

Michael

[Merkava_4]

M- 130202
T- 0135-04
C- 7202227

The carb was Briggs # 299437

I just wanted to make sure you didn't have the last generation of that model number : Type numbers 2903 thru 5510. That generation is a nightmare to tune and dial in.