Briggs 17.5 opposed twin will not restart when hot 42A707

[mitchstein443]

I am thinking about "what is the obvious"?
On my old B&S motors I create a ground to stop the sparkplug from firing. There is a kill switch for same with a small wire going to a ground.
Today's mowers have the "deadman switch" (maybe the wrong name) which requires one to hold the lever against the Push Bar. When released; the mower stops. First place I'd look is the complete deadman system, handles, springs wires to ground out the ignition. It could be that the ground wire switch is too close to the actual ground, thus the mower won't start when everything is hot. I'd also look for bent pieces around the springs, small wires and cables. Also look to see if the ground wire has too much insulation cut back on it (or the wire is loose), and the hot motor makes the switch get too close to a ground.

good point! but an easy way to know is to remove the negative wire from the coil and see if it fires then.. if it does then it is the kill wire (ground), if it doesn't then it is something else..

 

[mitchstein443]

Recommended to NOT wash a mower. Rust, corroded wires and connectors and so on. Power washers could get water in the oil sump with all that pressure. Key not working, corroded grounds to name some more.

Use compressed air, ScrubCadet 10 brushes, baby bottle brushes, degreaser then blow off and so on.

Use what ever method you have to clean the engine YEARLY or more if you scalp or bag. Some baggers dump a lot of grass on top of the engine.

oh, thats a load of malarky, been powerwashing small engines for over 35 years, its the first thing I always did before servicing and on my own equipment at least once a month, NEVER EVER had water get in the air cleaner/carb or oil. and I have washed every small motor from the predators to the 1960's opoosed twins..

I also do the samething on my camaro, yukon, xterra and prius.. never once had any issues with corroded wires or water damage..

However, if you do not kow what an air cleaner is, or what an oil cap is, hen don't power wash it, matter of fact do not touch it at all, go get a book and learn how an engine works before touching it at all..

 

[troy-built]

Depends if it's an OEM Briggs part or aftermarket? I've used a few aftermarket coils

????

It was an aftermarket coil.

 

[slomo]

oh, thats a load of malarky, been powerwashing small engines for over 35 years, its the first thing I always did before servicing and on my own equipment at least once a month, NEVER EVER had water get in the air cleaner/carb or oil. and I have washed every small motor from the predators to the 1960's opoosed twins..

I also do the samething on my camaro, yukon, xterra and prius.. never once had any issues with corroded wires or water damage..

However, if you do not kow what an air cleaner is, or what an oil cap is, hen don't power wash it, matter of fact do not touch it at all, go get a book and learn how an engine works before touching it at all..

Would be fabulous to live in a rust and corrosion free neighborhood like you. Guess I need to move.

 

[slomo]

Depends if it's an OEM Briggs part or aftermarket? I've used a few aftermarket coils

????

What was so funny? I too like a good joke. What did I miss Scrubcadet10?

 

[troy-built]

Ok I went out and worked on it for a while.
This is about as scientific as I get.
It's not as hot here today so I'm sure that's why the times are off from before. I checked the comp cold, the right cyl was 110 lbs and the left was also 110lbs.
I went and got my car timing light before I started it. Yea I know who has those these days. I checked the fire and both sides they were strong. I cranked it, it started right up. I went for a ride for 10 min. Turned it off at 23 after, started it at 25, 27, 30 and 40 after. It started every time.
Went for another ride for about 5 min. Cut it off. Tried starting it a 55 after NOTHING. Hooked up my timing light and just a little bit of spark once and a while on either cyl unhooked the ground on the coil the same thing no crank.
Then I did a compression check hot the right cyl was 110. and the Lt was 107. Not to bad I don't think.

What do you guys think the coil? The new one was bad? I have the old one back on there now.

 

[Ranamow]

my guess is your coil is bad had the same problem on two of my Toro ccr1000 snowblowers wound not start after being warmed up

That was my thought as well. I had 6.5 Briggs with the same issue, would start and run great but if you shut off, nothing. Then you had to wait a half hour and you were good to go! I finally put an old coil on that I had laying around, and works perfect.

 

[Scrubcadet10]

What was so funny? I too like a good joke. What did I miss Scrubcadet10?

You missed part of my quote.

 

[Scrubcadet10]

Ok I went out and worked on it for a while.
This is about as scientific as I get.
It's not as hot here today so I'm sure that's why the times are off from before. I checked the comp cold, the right cyl was 110 lbs and the left was also 110lbs.
I went and got my car timing light before I started it. Yea I know who has those these days. I checked the fire and both sides they were strong. I cranked it, it started right up. I went for a ride for 10 min. Turned it off at 23 after, started it at 25, 27, 30 and 40 after. It started every time.
Went for another ride for about 5 min. Cut it off. Tried starting it a 55 after NOTHING. Hooked up my timing light and just a little bit of spark once and a while on either cyl unhooked the ground on the coil the same thing no crank.
Then I did a compression check hot the right cyl was 110. and the Lt was 107. Not to bad I don't think.

What do you guys think the coil? The new one was bad? I have the old one back on there now.

Sure seems to be coil related...
could you post a link to the one you bought?

 

[troy-built]

Sure seems to be coil related...
could you post a link to the one you bought?

Sorry I don't have a link, I bought it on amazon just because it was easy. It wasn't a B&S, I'm going tomorrow to our local mower parts house and buy a real one.