Throttle problems: Engine only starts in slow (low) throttle

[cpurvis]

Were these pictures taken AFTER you cleaned the carburetor?

 

[DAMatson]

Good morning cpurvis!

I thought I had replied to this question yesterday, but I don't see the response now, so I'll reply again.

No, the pics were pre-tuneup and were taken so that I could see how all the linkages were run, so that I would have a "before pic" to refer to when it was time to put everything back together again.

-David

 

[cpurvis]

Good morning cpurvis!

I thought I had replied to this question yesterday, but I don't see the response now, so I'll reply again.

No, the pics were pre-tuneup and were taken so that I could see how all the linkages were run, so that I would have a "before pic" to refer to when it was time to put everything back together again.

-David

That's what I was hoping.

 

[DAMatson]

So were there any further thoughts on the throttle plate linkage being a potential part of my problem?

I'm not sure why there is extra slack to move the bracket back to the right in the direction of the arrows in the first pic of my last reply.

-David

 

[cpurvis]

So, I've soaked carb and parts in cleaner overnight, rebuilt the carb, and now the problem has gotten worse: I still cannot start the mower without using a little bit of primer gas in the carb, but now I can't even keep the engine going after starting it.

This suggests to me that your cleaning was partially effective--some dirt/debris has moved from one position to another but the carburetor is still not clean.

Did you remove the Welch plug and clean the passages under it?

I doubt that linkage is your problem. There is no direct connection between the throttle cable and the throttle plate. The throttle cable is connected to and sets a pre-load on the governor. The throttle shaft (and plate) is connected to the governor. When the engine rpm equals that preset by the operator, the pre-load on the governor and the force generated by the governor to close the throttle plate are in balance with each other.

 

[DAMatson]

Good afternoon cpurvis!

The Welch Plug is the only part I didn't look under specifically. Getting the Welch plug to stay put after removal has always been a nightmare for me in the past, but I did extra cleaning with carb-cleaner and copper wire for those jets pass under it, in the hopes that THAT would suffice.

Is there a recommended process for removing and re-installing the Welch Plug when I'm done cleaning the passages under it?

-David

 

[cpurvis]

I have drilled a small hole, being very careful not to bottom out the drill, then inserting a small sheet metal screw. Then I use a small pair of vice grips to pull the Welch plug out.

To install, drop the new plug in the hole, concave side down, then use a small hammer and drift punch about 2/3rds the side of the plug to expand it to fill the hole. The choice of using any sealant, such as Permatex, around the edge of the plug is yours; if you do use sealant, be careful to not use too much.

 

[DAMatson]

I have not had any success finding replacement Welch Plugs for this carb anywhere online. If I'm going to tear it apart again, I might as well replace all of the seals and o-rings, but those are going for about $15, and do not include a Welch Plug.

It would be pointless to take it out at this point if I can't find a replacement.

And, of course (Murphy's Law), now that I'm settled on the fact that a replacement Carburetor would be the way to go, those that were available online are no longer available... Sigh...

-David

 

[cpurvis]

Try a local lawnmower shop for the Welch plugs.

 

[Boudreaux In Eunice La.]

What carb do you have on there I have a bunch of welch plugs .............