Briggs 17.5 opposed twin will not restart when hot 42A707

[Scrubcadet10]

LOL I like that. I always say we need to contact Carnack. LOL

LOL yep,
That's my signature that appears with every post, from a former member

 

[hlw49]

see if you can get it to fire on Parts cleaner or starting fluid when hot.

Don't use starting fluid use gum out carb cleaner it won't blow the head off your engine.

 

[Scrubcadet10]

Yeah.

 

[troy-built]

Don't use starting fluid use gum out carb cleaner it won't blow the head off your engine.

I use very little when I do use it. A little goes a long way. But either one doesn't work. I think the next thing I'm going to do is adjust the valves. When I find out what they are set at.

 

[Scrubcadet10]

Keep in mind adjusting valves is a little more involved on a flat head than an OHV.
you need a bench grinder or something similar to take a slight amount of material off the valve stem end to reopen the clearance.... of course, that is if the valves are out of adjustment.

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Valve Clearance (Cold)
Springs Installed
Intake .004” – .006” (0.10 – 0.15 mm)
Exhaust .007” – .009” (0.17 – 0.22 mm)

 

[troy-built]

Keep in mind adjusting valves is a little more involved on a flat head than an OHV.
you need a bench grinder or something similar to take a slight amount of material off the valve stem end to reopen the clearance.... of course, that is if the valves are out of adjustment.

Google Drive: Sign-in

Access Google Drive with a Google account (for personal use) or Google Workspace account (for business use).

drive.google.com

Valve Clearance (Cold)
Springs Installed
Intake .004” – .006” (0.10 – 0.15 mm)
Exhaust .007” – .009” (0.17 – 0.22 mm)

Thank you, I was wondering about that and thanks for the manual link I haven't had any luck finding one.

 

[hlw49]

I use very little when I do use it. A little goes a long way. But either one doesn't work. I think the next thing I'm going to do is adjust the valves. When I find out what they are set at.

Gum out carb cleaner will no blow up your engine you can start it up and spray it in the carb and have someone else drive it in the shop while you keep it running on the stuff. Do it all the time.

 

[troy-built]

Gum out carb cleaner will no blow up your engine you can start it up and spray it in the carb and have someone else drive it in the shop while you keep it running on the stuff. Do it all the time.

Cool, I understand.
But if I have to keep something running with carb cleaner or what ever for long, I just stop and find out why it's not running right. I work on all of my own stuff myself I don't take anything to a shop.
I restored Corvettes for 35 years so working on things isn't a problem for me. But with trouble shooting it's good to ask others just in case they have had the same problem. Hence my question above.

But thanks anyways for the info.

 

[troy-built]

You know I have read a LOT of threads on here about motors not restarting when hot not just briggs, and I have read very few threads that figured out what the problem was. Why is that? Do people just give up? I don't understand.
I haven't worked on my mower for a few days as I like to get away from something like this to think it over. I will get back on it in a day or so. I have also thought and you know when I turn the mower off it will start right up just as long as you do it before 3 min pass. That's very odd it's got to be heat related.
I will figure this out because it looks like very few people on here have. At least that's what I have read.

Stay safe all.

 

[bertsmobile1]

We know why engine will not restart when hot
the problem is almost no one comes back with a
" the problem ended up being xyz, thank you"
so when others like you search, you see lots of suggestions but no solutions.

Without the engine right in front of us, all we can do is give you some tests to do .
You come back with the results of the tests then we can make a diagnosis

Only 3 reasons why a hot engine does not restart
1) bad spark
2) wrong fuel : air ratio
3) sticky valves

Having read through all of the posts and in particular the last one I would be looking at overheating .
So after 3 minutes with no airflow the carb has gotten so hot the fuel is vapourising in the float bowl or fuel lines
A lot of engines require a heat shield to prevent the fuel boiling in the fuel lines