Please tell me about Carbs...

[Harold Member]

I'm looking for advise, pro's & con's of the various carb selections available these days.

I have more experience with the Keihin & Mikuni type float bowl carbs commonly found on Japanese dirt bikes. I'm just recently learning about the Tillotson & the McCulloch type carbs & still don't know very much about them. I understand that a float bowl type carb would not work well on a chainsaw or any other application that would require the carb to be tilted too far from the vertical plane.

If you were considering converting one or more 2-stroke and 4-stroke engines to a type of carb that would provide a higher level of performance & adjust-ability... What would you choose & why?

Thank you.

[Tom Luttenbacher]

Tillitson....takes the external fuel pump out of the equation...but that too depends on your motor(4 cycle). Call EC Birt, speak with John. TL

[Harold Member]

Tillitson....takes the external fuel pump out of the equation...but that too depends on your motor(4 cycle). Call EC Birt, speak with John. TL

Tom,

I'm not familiar with the names or company in your post. Are they members of this board or do you have a link to a site I could look at? Thank you for your reply.




In the majority of my applications (Minibikes) I will be able to rely upon gravity feed.

I'm mostly looking for opinions on the various makes & types of carburators that are available to us these days. I'm not locked into the 'Historically Accurate Vintage Restoration' mindset. I'm more of a 'Resto-Rod' kinda guy & I try to tastefully mix the best of the new & the old. As I said earlier... the Tillotson & McCulloch flat top carbs are fairly new to me. I have heard about equal feedback from guys that think those carbs are the greatest & those that think they are junk. Obviously the truth lies somewhere in the middle & that's what I'd like to learn.

I was originally planning to replace the carbs on a few of my Briggs & Tecumseh engines with a Keihin type carb in the 16 to 20mm range. I'm of the opinion (...and I'm sure you know the old saying about opinions. LOL) that most of the Briggs & Tec type carbs were originally designed to operate best at maintaining 3600 RPM during various load conditions & may not be well suited to an application where the speed is constantly changing. I find it interesting that the factory Briggs racing engines use a Mikuni (I think) type round slide, float bowl type carb.

I recently picked up what I think is a very interesting carb. It appears to be a Tillotson type on top with a cable operated, flat slide below. The slide does not have a needle & jet arrangement like is typical on most slide operated float bowl carbs. It appears that it may provide a combination of the best of both designs. Then again... It may provide the worst of both. The previous owner is a pretty sharp guy with a solid history of Karting & general all around Gear-Head. He didn't seem to be very pleased with it & said that he was never able to get it to work quite right. I'll post a pic of it below.

I'm looking forward to the flood of information that this post will hopefully provide.

Thanks.

[Harold Member]

Does anyone know of any on-line manuals or guides on the Tillotson carbs?

I'd like to learn more about them, how they operate & how they are identified. What the various letters & numbers in the ID stand for.

Still interested in hearing the pros & cons of the various carb selections available these days.

Thanks

[Terry Sullivan]

Harold,
In my humble opinion, Tillotson is hard to beat for most 2-cycle engines.
I am also a stickler for originality. If you have a Mac with a functioning Mac carburetor, you might stick with it. If you are looking to replace a carb, go with the above advice and contact these guys - tell them what you have, take their advice and then fire that mother up!

http://www.eccarburetors.com/store/

I'm not sure what they have for documentation. If you send me your email address, I'll shoot you some Tilly docs I have.

terryas@mindspring.com

ps Are you near Atlanta?

Terry

[Harold Member]

Terry,

Thanks for that link. They have what looks to be an excellent Tech Page.
http://www.eccarburetors.com/technicalinfo.html

I've never been anywhere near Atlanta. Always been west of the Rocky's.