No throttle response

[viperv10]

Hello
I'm not sure what air valve you are talking about. It does have all 3 gaskets that go on a dura force carb. My problem might be that it is a cheap Chinese carb. Ebay is loaded with them.
Used to be that you could only get the oem ones that came unassembled. You have to put each piece together. That is a good learning experience. But any way I took it back off and everything inside is
is clean as a whistle. I turned the carb upside down and blew into the inlet tube. I could hear a tiny bit of air flow so I bent the float stem slightly so it would seal better. Tried it again and got dizzy from blowing so hard but heard no air coming through the needle and seat. Put it back together and it wouldn't start, not even with starting fluid. It does have good spark. My wife was watching the spark plug against
the fins while I was pulling the starter rope. I quit for the day and turned the gas shut off valve off. The next day I smelled gas in the garage and there was black oil under the muffler and underneath
the mower. I took the carb off again and replaced the new needle and seat with new lawn boy brand parts and it still leaks and still wont start. I did notice the Chinese carb had a 1pc. main jet instead
of the 2 pc. main jet and nozzle that comes on the original ones. Also there is no screen filter and it uses a cheap rubber bowl gasket.
I am going to take the carburetor off another dura force that runs good and swap it out and see if I can get it to run. If that doesn't work then I'm about out of ideas.
Regards
Jerry

 

[FuzzyDriver]

I don't know which is worse, unreliable junk new parts or the unavailablity of the air filter base and air filter cover on walbro carburetors. I'm going nutty trying to finish up the rebuild on this Walbro!

Are you sure your test was valid? I'm thinking that there''s a difference between the Δyour breath/weight of float and Δfuel pressure head/float buoyancy. I'd leave that known good carburetor on overnight, too, after you see if it runs.

Good luck - and, I don't guess you have any Walbro air filter parts laying around?

 

[viperv10]

Do you know what the model no. is of the mower or the part no.s of the air box and cover? Steel deck or alloy ? I have seen black air boxes and green covers on Ebay lately.
I have 4 or 5 F mowers around but I don't think I have any extra air filter covers, but I will look.
Regards,
Jerry

 

[FuzzyDriver]

I'm not sure that the exact part number matters on Lawn-Boy Walbro carburetors. I know that a few years ago I got a black one that had two rows of air inlets on the outside instead of the openings at the bottom that the green ones have and it worked fine. The exact match for this Walbro would be 612504 for the base and 611377 for the cover. All the models that start with S21 (~1989) are the same. I almost hate to mention this, but while you're looking, if you have a plastic carburetor air filter cover in very good shape I'd give you $25 for it. These have a turtle and a rabbit molded into the cover.and are part number 611376 (~1984).

I see you are in OH, I'm just across the border north of Toledo.

 

[viperv10]

Sorry, I couldn't find any filter boxes, but on ebay there is an air box #612504 black for $14.99.
I couldn't find a 611377 but if google part # 931231 several places have them. That's the one you were talking about that is black and has the 2 slots in the front.
I have a cover like that on a V engine lawn boy that came from Lowes. That stuff for the F engines is getting harder to find. Walbro's are getting harder to find also.
I found a NOS walbro 2 or 3 years that will fit on a lot of F engines, but they want a lot of money for them.
I'm about to go swap carbs now and see what happens.
Jerry

 

[viperv10]

I ordered a new toro carburetor yesterday morning on Amazon that came from Jack's small engines in Md. and it got here today. Now that's fast.
So I assembled all the parts and installed it on this problem child. I also checked the compression and it was 90 psi. I'm not sure were it should be.
But any how, the mower started on the first pull. It smoked a little but ran pretty good. I only let it run for about a minute because it was 11:00 at night
and I didn't want to upset the neighbors. Will check it out again tomorrow. The Toro or Lawn boy carbs have a main jet that screws into the nozzle.
The chinese one was one piece without the main jet. That might be part of the reason it wouldn't run. I don't know. I wouldn't recommend them to anyone.
I have used a lot aftermarket coils with good results though.
Regards
Jerry
PS
Oh the sweet smell of success, and 2 stroke exhaust.

 

[FuzzyDriver]

I have been searching for one for days, including 93-1231. All the hits I found ended in "Out of stock", "Unavailable", etc. Did you find one that was available?

V engine as in V-twin??

I don't need a Walbro carburetor, at least right now. I need to finish the three carburetors I'm working on first.

F engine compression when cold is 100-115, with a minimum of 80. Not sure if 90 is OK for the duraforce, but it is certainly good enough for the engine to run. I also have not had an issue with aftermarket coils. For that matter, I've found that a few minutes with my heat gun restores some original coils to work. This never makes sense to me, hot does cooking an electronic device make it start working again??

2-stroke exhaust...gotta love it. I use Klotz - smells even better, and the mosquitoes hate it.

-Mike

 

[viperv10]

The V engines I think might stand for value. They were sold in the nineties at box stores. They had black shrouds, black handles and steel decks, with plastic carbs. I believe the air filters and boxes
were the same size as on F engines. The ones I have seen were 4.75 hp and 2 stroke.
I googled lawn boy part 93-1231 and found several hits. https://www.russopower.com/parts/toro-93-1231

OMC Lawnboy Air Filter Cover 93-1231

OMC Lawnboy Air Filter Cover 93-1231 Replaces Toro 145831, Toro 609641, Toro 610177, Toro 610384, Toro 610728, Toro 610742, Toro 611376, Toro 611377, Toro 93-4303

partmartusa.com

https://powermowersales.com/Toro-93-1231.
Copy and paste each of these web pages and see if this helps.
Also look up lawn boy part 8481AE on Ebay, There is a used air box, cover and bolts for sale.
You are right the part # 612504 is out of stock or discontinued. Yesterday there was one on Ebay.
Regards,
Jerry

 

[intruder1500]

I have been searching for one for days, including 93-1231. All the hits I found ended in "Out of stock", "Unavailable", etc. Did you find one that was available?

V engine as in V-twin??

I don't need a Walbro carburetor, at least right now. I need to finish the three carburetors I'm working on first.

F engine compression when cold is 100-115, with a minimum of 80. Not sure if 90 is OK for the duraforce, but it is certainly good enough for the engine to run. I also have not had an issue with aftermarket coils. For that matter, I've found that a few minutes with my heat gun restores some original coils to work. This never makes sense to me, hot does cooking an electronic device make it start working again??

2-stroke exhaust...gotta love it. I use Klotz - smells even better, and the mosquitoes hate it.

-Mike

Possibly moisture in the coil itself and heating it up solves the problem.

 

[FuzzyDriver]

Jerry, I was trying to avoid that one on eBay because it's in Canada, but I went ahead and bought it today. Never bought any parts from up North before, crossing my fingers.

As many hours I've spent searching for that air cover you'd have thought I'd found Russo before. Thanks so much. I ordered 4 of them.

As many times as I've checked eBay, I don't see how I could have missed that 8481AE base. Maybe it just was put on in the last couple days - I know I've searched eBay for "Lawn-Boy Cover" lots of times. Anyway, thanks again!

-Mike