Outdoor Power Equipment and Small Engines - Briggs 16 2 cyl problems

Last week while messing around with this engine ( Birggs & Stratton 16 hp 2 clylinder 402707 model #) It would not start and I noticed the carb was filled with gas. I thought to myself lucky boy you have another carb just like this one, took the old one off and put the new one back on. Before I put the new one on I noticed the intake manafold was filled with gas and empty that the best I could, Ran the motor that day no probs but went to start it 2 days later and the hose that connects from the engine block to the air filter suddenly started blowing a gas / oil mix. Now I figure the gas got in the block when the carb over flowed would this cause it to blow back out that hose 2 days later. could I be in for just another oil change and cross my fingers ?

Crom

I doubt the problem waited for 2 days to show up. Sounds like the carb needle is not sealing, or the fuel pump is leaking through the crankcase tube.

Well I waited 2 days to run it again but you do think its still the carb I know I had to rebuild that anyway.


Crom

Well, you ran it after the carb swap with no problems, right? (on the first day). Then, 2 days later, oil/gas mix starts blowing into the filter housing. I don't know. You might just drain the oil, put the drain plug back in, let it sit a couple of days, and pull the drain plug back out to see if any more gas comes out. If so, you know it's still leaking. These carbs aren't hard to work on at all though. You'd probably just be ahead to take the old one apart, clean it up, check the float and change the needle and stick it back on.

crom60,

I overhauled one these carbs a couple weeks ago. These carbs have a fuel pump conected on the front. I would bet your first carb had a hanging float and the carb you now have installed has leaking pump diaphram. A very small hole in the diaphram will still pump but can leak gas into the crankcase.

I agree with Cheese, these carbs are easy to rebuild. When installing the tiny valve springs in the pump; use grease to hole the springs on their boosses when closing the pump cover.

God Bless,
Dave237

It sounds like your float is stuck or leaking. Take the float out, put it to your ear and shake it. If you can hear anything in it replace it, theres your problem
Gas/oil from inside the engine was blowing out the crankcase breather
Drain the oil and you will find that a good portion of gas is in the oil.
Running an engine this way will damage the cylinder walls.
Over choking can do this too.