Need shot of gas into choke to start

A

articaine

New Member
#1
#1
Hello to all!

I have a 3HP BS 80202, built in 1990. After searching thru the forum and making what I thought would be the solution the engine will not start unless I put a shot of gas into the carburetor via the choke. And then it will take a few tugs to start. I replaced the diaphragm, gasket carburetor head, new spark plug, cleaned the carburetor with cleaner, fuel pipe (no junk on screen).

So what to do? Thanks for the replies.
 
The_Ruppster_86

The_Ruppster_86

New Member
#2
#2
The carb may still be plugged with dirt and/or old gas. Usually "boiling" the carb or putting it in an ultrasonic machine fixes the problem. I have an ultrasonic machine at home that works great which I got from Harbor Freight. Make sure to buy the carb solution for it if you elect to go that route.

At my work we "boil" the carbs in a carb cleaning solution for 30 to 50 minutes. The carbs come out looking good and operate well.
 
The Restore Kid

The Restore Kid

New Member
#3
#3
The valve lash could be out of adjustment, giving you low compression.

The pickup tube could be cracked

The carburetor gasket and mounting surfaces could be loose, bent, cracked, and leaking.

The carburetor itself (throttle shaft) could be worn and leaking.

carburetor could be adjusted wrong.

Bad spark plug

When you changed the diaphragm, did you file the surfaces flat? http://www.oldminibikes.com/forum/b...s/59393-tech-trueing-your-diaphram-cover.html
 
A

articaine

New Member
#4
#4
Not sure where I can ultrasonic or boil the carb, so maybe I'll just try soaking it.

What is the valve lash? I did not see any visible cracks, perhaps I will look at it under magnification. NO, I did not true the surface. there is a new spark plug.

One bit of information that wasn't in the original post. The engine runs fine after it starts.
 
The Restore Kid

The Restore Kid

New Member
#5
#5
Could be valve lash.. Every so often through life you have to adjust the valves... The valve and valve seat burns away, and eventually the valve doesn't close at the right time....

THEN on these little motors, the camshaft already has a built in compression release, which is basically a controlled valve leak... It makes it start easier on the person starting it, and it's not so rough on itself....

SO, when the valve lash gets just a little out of whack, the intake valve pretty well never closes.. :facepalm:

So you have to set the valve lash, so the valves are closing at the correct time... You have to take the valve out, and grind just a tiny little bit off from the end on the valve stem...

Or, if it runs fine after it's started.. Just prime it to start it, and drive it.. :shrug:
 
A

articaine

New Member
#6
#6
The Restore Kid said:
Could be valve lash.. Every so often through life you have to adjust the valves... The valve and valve seat burns away, and eventually the valve doesn't close at the right time....

THEN on these little motors, the camshaft already has a built in compression release, which is basically a controlled valve leak... It makes it start easier on the person starting it, and it's not so rough on itself....

SO, when the valve lash gets just a little out of whack, the intake valve pretty well never closes.. :facepalm:

So you have to set the valve lash, so the valves are closing at the correct time... You have to take the valve out, and grind just a tiny little bit off from the end on the valve stem...

Or, if it runs fine after it's started.. Just prime it to start it, and drive it.. :shrug:
Click to expand...
When u say prime, I take it you mean put gas into the choke and pull on the crank. I came across this in another forum. Push-n-start Gas Cap / BRIGGS anyone have experience with this?
 
A

articaine

New Member
#9
#9
Thanks. Once I change out the diaphragm and it doesn't work I'll give this cap a try and post back. seems like a lot of gas being drawn up, or maybe pressure is sending the gas up the fuel tubes. Will see.
 
A

articaine

New Member
#10
#10
SUCCESS!!! I changed out the diaphragm and it starts. Although on the first attempt I had to open and close the choke several times :facepalm:, but it started. I let it sit awhile and then on the 2nd attempt it started with one pull. :thumbsup:

It was good to know I had that Push n Start option.
 
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