Antique Engines and Old Iron
[Home] - [HELP] - [Forums] - [Groups] - [Classified Ads] - [Subscribe] - [Books] - [Sponsors] -

Go Back   SmokStak > SmokStak® Antique Engine Community > Small Air Cooled Gasoline Engines
Forgot Password? Join Us!

Notices

Small Air Cooled Gasoline Engines Briggs & Stratton, Clinton, Lauson, Maytag, Nelson, Wisconsin and other small air cooled engines. Sub forums for mowers, scooters and powered eqipment.

Small Air Cooled Gasoline Engines

Briggs Pulsa Prime Cross Section / Functional Diagram?


this thread has 2 replies and has been viewed 367 times

Reply
 
Thread Tools Display Modes
  #1  
Old 03-08-2019, 02:00:38 PM
cancunia cancunia is offline
Registered
 
Join Date: Feb 2014
Location: Lincoln, Lincolnshire, England
Posts: 175
Thanks: 20
Thanked 25 Times in 17 Posts
Default Briggs Pulsa Prime Cross Section / Functional Diagram?

I'm curious to know how the Pulsa Prime actually works, what holes do what / how does the diaphragm control the fuel flow etc. Just wondered if anyone has a functional diagram or cross sectional image with a description?
I understand the basics, but it's the details I'm missing.

Thanks.
Reply With Quote
Sponsored Links
  #2  
Old 03-11-2019, 07:35:56 PM
Andrew Mackey Andrew Mackey is offline
Moderator
 
Join Date: Nov 2004
Location: Rockaway, New Jersey USA
Posts: 14,149
Thanks: 1,992
Thanked 6,767 Times in 4,301 Posts
Default Re: Briggs Pulsa Prime Cross Section / Functional Diagram?

If you are talking about the carburetor that has the diaphram on the side, there were 2 styles. I believe here in the US, one was called the pulsa jet. In either case, the diaphram has a spring and 'washe'r that provides slight pressure against the rubber material. As the engine goes thru the intake cycle, the atmospheric pressure in the throat of the carb decreases and pulls the diaphram toward the carb bore. This draws fuel from the tank past one of the small flaps on the diaphram into the chamber behind it. As the engine gets to TDC, the suction decreases and spring pressure now forces fuel out past a second small flap into a reservoir where it then passes the fuel feed adjustment needle and into the carb. On larger fuel tank engines, this reservoir feeds gas to a second small reservoir in the tank, and engine suction thru a second tube then feeds fuel to the jet and fuel adjuster. On both carbs, the smaller reservoir has a notch that allows excess fuel to return to the tank. On some engines, there was a primer that provided the pulse against the diaphram without the engine running. This both filled the tank reservoir and primed the carb for easy starting. all of these carbs suffered with the advent of E-10 crap fuel - it hardened the diaphrams and ate the rubber primers The pick up tube from the tank had a steel ball as a check. The second (short) pick up didn't. It was short enough to not need a check.
Reply With Quote
  #3  
Old 03-11-2019, 09:27:32 PM
gdstew gdstew is offline
Registered
 
Join Date: Jan 2015
Location: New Philadelphia, Ohio, USA
Posts: 1,046
Thanks: 293
Thanked 592 Times in 385 Posts
Default Re: Briggs Pulsa Prime Cross Section / Functional Diagram?

" On some engines, there was a primer that provided the pulse against the diaphram without the engine running."


I don't recall any carbs with side diaphragms that used primers, please refresh my memory.




" The pick up tube from the tank had a steel ball as a check."



Only the 1 tube suction carbs had the ball check valve. The carb with the long and short tubes and the diaphragm on the side used the 2 small "flappers" on the diaphragm as check valves.
Reply With Quote
The Following 2 Users Say Thank You to gdstew For This Post:
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

F o r u m Jump

Similar Threads Chosen at Random
Thread Thread Starter F o r u m Replies Last Post
Cross section view The Diesel Doctor Vintage Diesel and Oil Stationary Engines 0 01-15-2017 07:27:24 PM
Chicago Injector cross section? 600 Megawatts Steam Stationary Engines, Traction Engines 5 02-27-2015 09:03:06 PM
Maytag Coil Cross Section View Mark Shulaw Maytag Engines and Collectibles 0 03-13-2013 04:46:43 PM
Need help with Briggs Pulsa-jet carb Leonard Keifer Small Air Cooled Gasoline Engines 2 03-26-2006 09:19:57 AM
Buzz Coil Cross Section Mike Inglis Antique Engine Archives 2 11-20-2004 03:29:30 PM


Use "Ctrl" mouse wheel to change screen size.
All times are GMT -4. The time now is 09:09:17 PM.

Smokstak and Enginads site search!


All use is subject to our TERMS OF SERVICE
SMOKSTAK® is a Registered Trade Mark - A Community of Antique Engine Enthusiasts
Copyright © 2000 - 2019 by Harry Matthews P.O. Box 5612 - Sarasota, FL 34277