Briggs Stratton Experts..........

I have a Poulan garden tractor with a 24hp Briggs & Stratton V twin engine. About 500 hours on it.

It ran normally the last time I used it. Went to pull a little lawn trailer with it this afternoon. It started right up, smoked a bit, and stopped after about 10 seconds. After it sat for a bit, it started right up again, threw heavy bluish white smoke out of the exhaust, and stopped again after about 10 seconds. It did that several times before I gave up and quit trying.

I checked the oil and it was 'way over full. Would a failed intake manifold gasket do that? Any other ideas? When it ran it didn't misfire, just smoked a lot. This engine did bend several push rods a couple of years ago until I fabricated reinforced pushrods and began using synthetic oil. No other problems with it since.

If anyone has any ides, I'm all ears.

Thanks in advance.

Needle valve in the carb got a piece of dirt under it, and leaked fuel into the crankcase. The arb floods, the fuel fills the intake, and flows past the rings into the crankcase. Change the oil, make sure the float shuts off the flow. Jim

If the fuel tank is above the carburetor, the carb float needle valve is leaking. Gas overflows the carb bowl, drains into the manifold then by the pistons into the crankcase.

The carb needs attention (internal clean) and the oil needs to be changed.

Not sure on the oil level, but Inteks are bad about blowing the head gasket. Leaks from the pushrod area into the chamber causes bad smoking and oil burning.

If it runs good otherwise but keeps leaking filling the crankcase. Put a shutoff in the fuel line. I get them from TSC that fits 1/4" line

Yep, been there done that. Crankcase is filling with fuel due to a bad needle and or seat. Did a thorough carb cleaning and changed the fuel line because I thought it was breaking apart inside. Didnt help. Changed the carb and all was well again. Your choice, install a fuel shutoff that you may forget to shut off or just change the carb.

I have one that the fuel pump ruptured. It is like on a snowmobile and has a pulse line to work the diaphram and pump the gas. It ruptured and would pump gas into the crankcase. It never got to the point that it wouldn't run right, but when I checked the oil the crankcase was getting fuller. Hope this helps.

Steven

Good Afternoon Goose
You need to need to get the needle & seat fixed , If you continue to put fuel into the oil you will wipe out the crank bearing . Then its a short block or new engine.


AZpeapicker

I agree with steven id. check out the fuel pump it"s either that or needle and seat. If the fuel tank is mounted high enough you may be able to bypass the pump and gravity feed the system.

I'm inclined to agree with Steven and Leroy about ruptured pump diaphragm. If it was a gravity feed with leaking needle it would flood much worse and be difficult (maybe impossible) to start but once running there's no reason to die. On the other hand pump diaphragm leak's less when not running and isn't sevearly flooded when started. Once engine is running air pulses from crankcase tube leak through diaphragm and blow's fuel back instead of pulling fuel as it's supposed to. IMO,OE carb is far better than aftermarkets. Genuine Briggs replacements are very expensive so I rebuild OE with Briggs labeled kits if and when rebuild become's necessary. Before rebuilding gravity feed,I first "lap needle in seat"with valve paste or auto paint polishing compound and that usually fixes it. On diaphragm pumps,I block the pulse tube then install a 12v in-line pump. This issue has caused failures in what is otherwise near builtproof engines. It contributs to both, bent push rods and short engine life. That B&S hasn't made a simple change is hard to believe. Truly one of those situations where "a stitch in time save's nine"when buying machines with B&S engines.

Thanks, Goose. The last time I used the V twin powered pressure washer it smoked when started. I checked the oil and found it over filled. I drained some out and thought I must have put too much oil in. Now I bet I have the same thing going on. Time to change the oil again. You may have saved my motor with your question.

That particular carb has a rubber needle tip and an aluminum seat. The aluminum seat is junk and wont seal properly. I have put a shut off valve inline and works good if you remember to shut it off when done using it.

The fuel tank is under the seat, so it has to have the pump.

The fuel pump might be the first thing to suspect. I'll seriously dig into it today, if I have time.

Actually, this seems eerily familiar. We have another mower/garden tractor with a 17.5hp single cylinder Briggs engine. It did something similar a year ago, but it has a gravity flow tank. I tried two different new $20 aftermarket carburetors then, and they each had their own problems and I was able to return both for a refund. I sprung $90 for a new OEM carb and the problem was solved.