7 HP Flathead carb/governer setup with twist throttle

Thepaetsguy

Well-Known Member
#5
Ahh good were talking about briggs.. Only two ways I know to do it reliably.

Big flatheads are scary if your willing. I ran one “nearly” to death and quit trying to blow it up on purpose when it got hard to start and burnt two bottles of bar&chain oil in 4 miles. EB67B114-440E-43D8-8F6B-497F64EAC2DE.jpeg D5844E96-AC8D-48D1-9B74-84CFC80306C6.png CC0CABD0-398B-446F-AF07-74CF1ED77C35.jpeg 3815648D-7A32-4499-995F-9A6D0ED331AD.jpeg
 
#7
That big block in the diagram has the points outside of the block?? I see the push button shutoff. Never new briggs did that.
I think it was only the big cast iron ones with the points out there.
I'm surprised bar and chain oil would splash enough to run for even 5 minutes. We ran a vertical shaft 6 horse so hard it was blowing oil out the exhaust, so we put a quart of 90 weight gear oil in it. It SMOKED, stunk, chugged and threw the rod out through the block.
 

Harquebus

Well-Known Member
#8
From the OP photo, it looks as though a throttle cable could be used on either side of the governor control's pivot point. Make sure the return spring is stout enough and snaps the throttle back to idle once the grip is released. I think Harbor Freight sells a spring assortment in a clear plastic box.

A twist throttle requires braided cable so the rigid wire with a Z bend on the end presents a problem (as seen on the yellow engine photo that Thepaetsguy provided). Use regular braided cable and add a throttle cable cleavis on the end that will attach to the pivoting governor mechanism. Flatten the loop end of the cotter pin/split pin if needed (make it resemble a nail head) or bend the tab out a little for clearance.

https://www.OldMiniBikes.com/throttle-clevis.html



Interesting. What's the serial number or engine series on this engine, Gorak?
 

Thepaetsguy

Well-Known Member
#9
throttle cable could be used on either side of the governor control's pivot point. Make sure the return spring is stout enough and snaps the throttle back to idle once the grip is released. I think Harbor Freight sells a spring assortment in a clear plastic box.

A twist throttle requires braided cable so the rigid wire with a Z bend on the end presents a problem (as seen on the yellow engine photo that Thepaetsguy provided).
My post #5 picture #1 is a minibike twist grip. The hole on the pivot linkage was drilled out (be carful doing this) and a standard twist throttle cable end was press fit through the hole.

The return spring was then added to ensure the press fit cable could never slip out.
 
#10
From the OP photo, it looks as though a throttle cable could be used on either side of the governor control's pivot point. Make sure the return spring is stout enough and snaps the throttle back to idle once the grip is released. I think Harbor Freight sells a spring assortment in a clear plastic box.

A twist throttle requires braided cable so the rigid wire with a Z bend on the end presents a problem (as seen on the yellow engine photo that Thepaetsguy provided). Use regular braided cable and add a throttle cable cleavis on the end that will attach to the pivoting governor mechanism. Flatten the loop end of the cotter pin/split pin if needed (make it resemble a nail head) or bend the tab out a little for clearance.

https://www.OldMiniBikes.com/throttle-clevis.html



Interesting. What's the serial number or engine series on this engine, Gorak?
 

Attachments

#14
As RPM increases, the governor arm will pull against the spring to try to close the throttle. A stiffer spring will allow more RPM, because it makes the governor arm pull harder to reduce the throttle opening.
Idle RPM and/ or quality are not affected by the governor.
 

Harquebus

Well-Known Member
#17
The only thing Gorak needs to do then, is remove the throttle control rod seen in the photo post #1 {has the knurled knob on the end} and fashion a minibike throttle cable-linkage in its place. The governor/throttle assembly is removed from the engine in that photo so it is hard to visualize, but I imagine he can adapt the common #692316 Briggs and Stratton Throttle Control set and make it work..... https://oldminibikes.com/forum/inde...eded-5hp-leaf-blower-b-s.167109/#post-1220986

This throttle configuration was published in the 'Briggs and Stratton: Service manual for Out of Production Engines - 1919 - 1981'. The throttle is operated with a solid wire type cable and did not require a throttle return spring.
Sounds like a stationary engine setup or some application (tractor?) where you wanted constant speed but did not want to hold the throttle by hand. Could still work on a minibike but it wouldn't be ideal.
 
#18
That threaded rod with the knurled nut on top would connect to the throttle control under the gas tank, which has a spring connecting it to the governor arm. There is probably a place to clamp a cable under that tank to connect to the same throttle control assembly.
 

Harquebus

Well-Known Member
#19
I took the liberty of adding some high tech scribbles on his photo. A possible setup, but by no means THE setup.

Parts Description (hope no one is color blind):
Green is the throttle cable housing
Yellow is a cable holding ferrule
Blue is the inner wire with a "swaged end" (a clevis can also go there)
Red is the 5926 Spring Anchor (Item 7)
Blue is the 5927 Spring (Item 8)

These part numbers are in reference to the Briggs drawing at the link I supplied in Post #17 and from the #692316 Briggs and Stratton Throttle Control set. *Drawing is below the photo.

Even though his engine is fairly different from 3, 4 and 5 HP minibike engines, it looks like it can accommodate the 5926 Spring Anchor (Item 7) and the 1628 Cable Retainer (Item 2) on either side of the rotating governor control (see the double holes) for more cable routing options.

Image 148.jpeg

Image 159.jpeg
 
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