Someone recently gave me a lawn mower. It wouldn't run at all. It had gas pouring out of the primer bulb. So I replaced the needle and seat. Now it runs but doesn't seem to have any power. When it hits the slightest amount of grass it will bogg down and die. I've attempted to adjust the governer and high idle but that doesn't help. Even with higher RPMs it still boggs down. The engine is a tecumseh TVS90.

well. make sure the carb is set right, 1.5turns out from all the way in, then fine tune, going till it runs rough, then going till it slows down, and middle way. also. the engine may not be running at its full rpm limit. the governor may be set wrong. but then again they are picky little things.

I don't think the carb has any adjustments on it other than idle and high speed. I've looked on it but couldn't find anything else to adjust. I've discovered that it has an air leak around the intake. Could this be causing my problem?

somewhat, make sure thats nice and tight. then see if that helps any, if not the governor may need an adjustment, running to low of rpms to give full power

Sounds like you have a compression problem. On a 4 stroke engine you have a intake, compression, power, and exhaust stroke in that order. If you dont have any compression you wont have any power. Check the compression with a compression gauge. Screw the compression gauge where the spark plug goes and crank it acouple of times if the pressure starts to go down you have a leak. Check all the gaskets on the cylinder and also your compression rings on the piston.

A air leak at the intake manifold will cut down the amount of air/fuel going in the compression chamber causing less power. If it's leaking to bad the engine wont produce enough power to keep it going.

I replaced the gasket and the problem is still there. I sprayed carb cleaner around the intake and carb to check for leaks and it seemed to be ok. At first the RPM's are high enough but as soon as it his the grass it will bog down and almost die. If I pull it back out of the grass the RPM's will very slowly increase back to normal.

Is it possible to somehow check the compression without a guage? Anymore ideas?

I have this same problem, I think valves may kneed to be reseated.

well, there is one ( quick one ) put your thumb over the plug hole, and turn the engine over, and if it blows it off, it would have enough compression, but even then that really doesn't do great. a shop should be able to check it for you. though valves that don't seat well, that'll effect it.