OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs 35 Series Caught Fire

Hey Guys,
This is something I have not seen before and was after some comments on why/how etc. Yes I know it has caught fire but I am after some reasons? Just some genuine thoughts as I am a little perplexed.
The mower despite the fire damage is in relatively good condition. The base and wheels are great and the actual base engine block seems un-damaged. The previous owner said it was still running when we smothered the fire but who knows!
I had to remove the starter and coil as they were damaged beyond repair. I haven�t taken the carby off as I wasn�t 100% sure about how to remove it as the plastic has gone rock hard. I was thinking of using my multi-tool but was after some better suggestions?
Interesting to me at least anyway. Would love some thoughts as I think it is salvageable with the parts from one of the many donor engines I have available with bent crankshafts that are yet to be stripped.
Jaffa

Hey Jaffa if they got fuel on top of the carby/tank then all that is needed is an ignition source, only one that comes to mind, is when you put the controller to stop you get arcing at the stop contact, which is around that area. (but who knows what they were doing)

Here is a burnt out Victa I rebuilt, the back was choked full of grass and more than likely soaked with fuel.
It was extinguished with a powder extinguisher. Owner wont tell you what really happen, probably embarrassed.

It is fairly common for ill-tuned engines to do a "lean spit" through the carburetor, especially during shut-down. Eventually you sort of automatically watch for it. The ancient Kirby-Lauson engine'd rotary I had about a thousand years ago set fire to its air cleaner when I shut it down one day. I was very, very tempted to let it burn, but I finally put it out - though I've never been sure it was a good idea.

Long ago when cars had carburetors and some slackers or hoons left off the air cleaners, it was not terribly uncommon to see cars with burned areas on the bonnet directly above the carburetor.

Mark - Nice work on the trusty Victa 2 stroke. Being a Cast Iron Block it would have stood up well to the additional heat!

Grumpy - Thanks for the explanation - I should have added the previous owner mentioned the mower was left running by their father inlaw in long grass. I suppose the additional heat and dry grass could have made it catch fire.

I am learning towards the grass in the mower being soaked in petrol - this particular mower was pretty clogged up full of grass.

I dont suppose you have any suggestions about removing the melted plastic? I was thinking of my multi-tool.

Jaffa

I tend to start off with something like a screwdriver, prising the plastic up where it wraps around one of the metal parts. It doesn't matter whether the plastic bends or breaks, of course. I doubt it will be chemically stuck to metal, it will probably just be moulded onto it, so you work around the outside levering it away from the metal. After a while the chunks that would not bend far enough to release the metal, get broken off. If it is both very strong and rather flexible, you end up having to cut off the wrapped areas, with something like a very short saw - you probably have one of those on your multitool, but I use a sort of handle that mounts a broken off piece of hacksaw blade (I tend to have more than enough broken hacksaw blades, and I don't mind breaking them again).

Really to get the bulk of that gone, all you would need is to get at that half inch bolt holding the tank on and the 3/8 bolt on the front, I would support the tank underneath by wedging something solid between the tank and the base (to prevent breaking the tab that holds the thread for the 1/2 inch bolt, and pry away at the plastic with a screwdriver, chances are the govenor springs may be melted into that mess, so A wise approach would be to remove the top 3 head bolts and ignition coil and tank as one assembly.

I have seen the fuel tanks break and leak where the 1/2 inch bolt holds them in, ample fuel would spill out to start a fire, all you would need is enough heat for it to hit the flashpoint.

once you get it stripped down, you'll probably find the main block assembly will be fine, I have ressurrected worse, and the victa base in the pics looks worthwhile to put a good engine on.

Project complete. Once all the fire damaged plastic was removed it was a pretty easy repair.The engine came up really nice and runs spot on. A pretty low cost repair all up. Fire damaged item was a trade at no cost. Spares came off an engine with a bent crankshaft that I also picked up for free. So just some blades, fresh oil, carby diaphram and some carby cleaner was really all that was used for this project. It didnt last long before it went to a new home!

Joe you were correct the block was un-damaged. It hardly had a mark on it.

Thanks for your help, Joe, Grumpy & Mark. I have included some photos of the finished project.

Another "hopeless case" rescued without much cost or work - well done Peter. Small carburetor fires need not be disastrous on tank-under-carburetor engines, but they are certainly dangerous if the fuel boils in the tank, especially if the tank cap is not a metal one. I recommend keeping away from burning mowers if they have gravity feed engines though.

Thanks Grumpy. You are correct this was a relatively easy fix at low cost - A more than worthwhile project which hopefully shows others its worth fixing mowers with minor fire damaged engines, well at least in this case it was anyhow.

Hi Jaffa, and many thanks for posting this topic and with great pics...This thread will be great for the archives and may give another member confidence to tackle a fire damaged machine in the future...