Briggs & Stratton Model #294777 Rough Idle & Killing

Purchased new September 1998.
Agco Allis (Simplicity) 1614 VH riding mower with 38” deck.
B & S Model #294777 Twin cylinder 14 hp Vanguard.

Problems started last year (2018) Motor begins to run rough. This happened both when I was mowing, & when just driving the mower.
Most times, it would come out of it, & return to normal.
This year it started & ran fine during the first mowing, but then that same rough running (missing) began, & it killed. Unlike the previous years, this time when I tried to restart it, there was nothing. Waited about 5 minutes, & it started right up & ran fine for the duration.

The next day it started fine, so I drove it outside where the light was better, removed the shroud, & cleaned up the mess that mice had made. One of the cylinders was completely covered. It was a mess. I felt confident that this was causing the motor to overheat & therefore causing the problems. I mowed the hillside, which was very tall & damp, & it ran fine. When I was done, I disengaged the deck & drove it towards the shed (about 30 yards) shortly before I reached it, the rough running (missing) returned & it killed. Once again, when I tried to start it, there was nothing. This time, even though I waited about 2 hours, there was nothing when I turned the key.

The next day we took the shroud off again, & did an even more thorough job of cleaning out the mess left by the mice.
Started it, mowed a small section (12 minutes) but once again, after the mowing was completed, while backing it into the shed, it started to miss & killed.
It started right back up, but was running rough. Approximately an hour later, I tried it again & there was nothing ?

Misc.
The battery is fine (new in 2018)
Spark plugs: (new in 2018)
Air Filter: I don't believe it has ever been replaced, but I clean it religiously.
The coils are fine. Good spark on both plugs.

Any ideas/suggestions would be appreciated.

Remove the rocker covers and check the valve lash.
Also measure the height of the valve when the piston is just past TDC so both valves are closed.
They should be the same inlet & exhaust.
Overheating causes the head to soften and allows the valve guide to shift in the head.

bertsmobile1 said:

Remove the rocker covers and check the valve lash.
Also measure the height of the valve when the piston is just past TDC so both valves are closed.
They should be the same inlet & exhaust.
Overheating causes the head to soften and allows the valve guide to shift in the head.

Click to expand...

Thanks for the suggestion. We'll try that when time allows.

I too had a mouse problem on a similar engine but was lucky to catch it before it caused problems. Now I have an 8mm nut driver handy so that I can remove the flywheel screen for inspection before each use.
Attached is a picture of a nest which was constructed in a few days.
I was thinking that it would be a good idea if one could install a temperature gauge for each cylinder. I bet someone makes them.

Rideau1 said:

I too had a mouse problem on a similar engine but was lucky to catch it before it caused problems. Now I have an 8mm nut driver handy so that I can remove the flywheel screen for inspection before each use.
Attached is a picture of a nest which was constructed in a few days.View attachment 44137
I was thinking that it would be a good idea if one could install a temperature gauge for each cylinder. I bet someone makes them.

Click to expand...

Those damm rodents!
Have you ever heard of mothballs being a deterrent for mice ?
Back in the 80s, when I stored a car in an old tin shed on a farm over the winter, I put mothballs around all the tires.
It's been so long ago now, I can't be certain, but I don't recall having any mice damage in the car the next spring.

I did a Google search, & like many things a person researches, you get different answers.
The first site said that mothballs aren't a deterrent for mice, so of course the next site said they were.

Here are some common household products that you can use to prevent mice from taking up residence in your home.
Moth Balls
Ammonia
Fabric Softener Sheets
Peppermint

The trick is a shed cat.
Locked in all night but not fed till the morning so it is hungry & hunting all night.
Despite popular belief that they were domesticated purely to make fun videos of, cats were domistacted to protect peoples grain from rats & mice .

bertsmobile1 said:

The trick is a shed cat.
Locked in all night but not fed till the morning so it is hungry & hunting all night.
Despite popular belief that they were domesticated purely to make fun videos of, cats were domistacted to protect peoples grain from rats & mice .

Click to expand...

Agreed: We used to have 2 of those, but now we don't have any.

giganticoverturn said:

Those damm rodents!
Have you ever heard of mothballs being a deterrent for mice ?
Back in the 80s, when I stored a car in an old tin shed on a farm over the winter, I put mothballs around all the tires.
It's been so long ago now, I can't be certain, but I don't recall having any mice damage in the car the next spring.

I did a Google search, & like many things a person researches, you get different answers.
The first site said that mothballs aren't a deterrent for mice, so of course the next site said they were.

Here are some common household products that you can use to prevent mice from taking up residence in your home.
Moth Balls
Ammonia
Fabric Softener Sheets
Peppermint

Click to expand...

I've tried all except ammonia.
I believe that moth balls are effective but I haven't been able to find them of late. All that seem to be available are tablet like items in a small pouch. They seem to be less potent and don't last like balls.
I currently am protecting my tractor with moth ball like items, dryer sheets and an ultrasonic repellent. Last year the cute little critters ate a lot of insulation from wires going to the fuse panel. They do a lot of damage for such small animals.

bertsmobile1 said:

The trick is a shed cat.
Locked in all night but not fed till the morning so it is hungry & hunting all night.
Despite popular belief that they were domesticated purely to make fun videos of, cats were domistacted to protect peoples grain from rats & mice .

Click to expand...

I'd love to have a cat but can't because my equipment is at a cottage which I only visit in the warmer weather. It gets darn cold in the winter. The shelter is a portable shelter (good one though) 12x30 and very easy for the mice to get in. In the summer, some larger snakes help but they disappear when it gets cold. I hope to build a mouse proof garage next year.

We still haven't been able to find the problem, so we decided to take it to a pro. He's behind now, so he may not be able to get to it for a couple weeks. When/if he fixes it, I'll update.