Need orifice size of main jet for 5hp pulsa-jet carb

[Telesis]

Engine is a 5HP Briggs horizontal shaft I/C engine. 132212-0362-01 Carb part number: 492611
It utilizes a fixed jet in the pickup and mine is plugged. The engineer in me would like to know what the actual jet size is and then I can run a micro-drill in to clean it out. Based on my experience, I'm guessing I could use a .020 to start and the engine would likely be OK but that's a guess. I'm thinking it's bigger than that.

I've looked all over the net but can't find that piece of data. Maybe one of you know or have this common carb or equivalent on the shelf and could give me an idea how big it is.

Thanks in advance for your consideration. Any help appreciated. Thanks!

 

[Rivets]

I’ve been doing this for over 50 years and this would be the first time I’ve heard that the pickup oriface being plugged. Never seen spec on this. Are you sure that is the problem? Most common problem with those carbs is that the pump diaphragm is old and not pumping properly to draw fuel from the tank to the auxiliary tank. Have you checked that the auxiliary tank is full of fuel? Have you replaced the diaphragm? I would start here before drilling.

 

[StarTech]

First it appears someone has changed the carb as the IPLs has it using a regular adjustment needle but that was the original carb too. But those fix idle mixture jets are somewhere between a #80 and a #75 drill bit; closer to the #75. Possible #76 but I don't have that one here yet.

 

[Telesis]

Thanks guys. Yes Rivets I'm positive it's plugged. I have it in my hand and it's real easy to blow on the pickup and no joy. (I agree 90% of the time it's a bad diaphragm and/or a dirty/plugged tank pickup screen. Otherwise they are pretty bulletproof. The diaphragm in this carb was toast and clearly it's been sitting a long time)

Based on your data StarTech, I think I'll use an .020 and give it a whirl.

Thanks again for your prompt responses. Happy 4th!

 

[Telesis]

I thought I'd make one more observation since Star mentioned this may not be the original carb. When I look at a Briggs 498298 carb, it does indicate for example, that it is a sub for the part (492611) that is listed in each of two IPL's (new from current B&S site and original/old) I have for this engine. When I look at all the photos of the 498298, it is exactly the same as what I have including the fixed main jet.

So I'm guessing I misunderstood what you were trying to tell me. If you don't mind Star, can you clarify what you meant please?

Again, thanks!

 

[Rivets]

Now I’m confused. There is a main pickup tube (long one) through which the pump draws fuel from the main tank to fill the auxiliary tank. Then there is the nozzle through which the fuel is draw from the auxiliary tank into the carb body. Neither one of these has a jet. Where is the jet you are talking about located. Second, if you plan on drilling out a clogged jet I recommend you start with a number 78 drill, (.016”) first. If it doesn’t do the job for you, you can always go larger. Finally, do you have the original carb 492611 with an adjustable idle screw or superseded carb 498298 with fixed idle jet?

 

[Telesis]

I thought I'd make one more observation since Star mentioned this may not be the original carb. When I look at a Briggs 498298 carb, it does indicate for example, that it is a sub for the part (492611) that is listed in each of two IPL's (new from current B&S site and original/old) I have for this engine. When I look at all the photos of the 498298, it is exactly the same as what I have including the fixed main jet.

So I'm guessing I misunderstood what you were trying to tell me. If you don't mind Star, can you clarify what you meant please?

Again, thanks!

 

[Telesis]

Sorry for the confusion Rivets. I'm referring to the nozzle that is drawing fuel from the aux tank into the carb body. That has a brass insert with a small orifice which I assumed, perhaps wrongly, was the "fixed main jet". If you look up a Briggs 49828 on their store and look at the bottom view of the carb, you can see what I'm referring to. If that is not the fixed main jet, I apologize for the wrong terminology. In any event, that is what is plugged on mine, and that is what I was originally trying to find the size of.

I hope this demystifies it a bit.

 

[Telesis]

Sorry for the confusion Rivets. I'm referring to the nozzle that is drawing fuel from the aux tank into the carb body. That has a brass insert with a small orifice which I assumed, perhaps wrongly, was the "fixed main jet". If you look up a Briggs 49828 on their store and look at the bottom view of the carb, you can see what I'm referring to. If that is not the fixed main jet, I apologize for the wrong terminology. In any event, that is what is plugged on mine, and that is what I was originally trying to find the size of.

I hope this demystifies it a bit.

498298 (missed a digit)

 

[Telesis]

I have the adjustable idle screw.