Outdoor Power Equipment and Small Engines - blow back out of intake

I have a dead?? 22 horse 2 cylinder B&S INtek engine. The first solvable problem it had was a bad fuel pump, as you turn the engine over it would squirt gas out of small hole in the center. Installed new pump and observer the folowing- gas pumps through it into carb properly. Discover new problem it will start and run ok with a little choke but the throttle won't go up and down only a high idle. You cannot install the air filter and it's screws, this causes the engine to die immediately.

My previous experience playing with single cylinder engines is there should be a vacuum always around the intake (varies with each stroke of course,) but no blow back. This one has visible vaporous gas /air mixture blow out of the intake and then most of it goes back in. You can set the throttle anwhere you want it will contine to run a little higher than idle.

It is 3 or 4 years old rusting already poulan pro tractor, el-cheapo from home-depot. Do I just chuck it and get a new one or is there an easy fix here?

Thanks in advance!

Check for fuel in your oil, gas may have entered the crankcase through the fuel pump and the crankcase may be well overfull with gas and oil mixture. Oil and gas may be coming out of the breather tube and choking the engine down.

The other possibility is that you may have an intake valve sticking on one of the cylinders, this could be determined by removing the valve covers and checking the valve lash on the intake valves. It's also possible for one of the exhaust valves may not be working properly and causing a problem as well.

Thank you for your reply. I fixed it this evening before reading your post... but you were RIGHT ON. opened both OHV covers and one had it's lifter rod fall out of place and the intake (top one) was stuck in. Took lots of tinkering to get it free a little heat, tapping inward, vice grips pull it out. But I got it and when reassembled the beast ran fine.

I don't think it is was burnt on the inside, I think it was getting dry maybe? Oil was up to the mark. Maybe it needs an oil change. How often should I change oil and filter.

Anything specific you would recommend to prevent this?

With sincere thanks!

Keep the cooling system clean, oil and filter change every 50 hours of operation, periodic valve lash adjustments.

Old stale gas alos seems to make the valves stick, especially on the twin cylinder inteks for some reason.