My K750 Partner Fires up real eazy, idle fine.will only run at full throttle for 5 to 10 seconds then dies

There is throttle plate adjustment and idle air mixture adjustment x2 so 3 items to adjust.If the carb is clean and you have NO vacuum leaks the engine should run fine.One trick for a better idle is to run full vacuum at idle speed on the dist vac advance if you have a vac advance rather than a ported vacuum which applies vac only at open throttle.

Take a look at the linkage between the throttle trigger and the carb. There should be a small screw that when turned in will increase the idle speed. This screw most often pushes on the linkage opening the throttle plate in the carb to speed up the engine.

Check valve lash

I had a saw with a similar problem. I beleive you need a new carberator. I changed mine and my saw never ran so good. I think from all the vibration all the shafts/bushings have wore and now air is being sucked in from too many unwanted places keeping enough vacume to **** the gas out of the carb bowl.

check the fuel filter in the petrol tank

sounds to me like your check valve in fuel line is not working. If you have the original lift pump it located in there.

sounds real easy either a bad idle air control solenoid or more likley a blown throttle body gasket. to test fro a blown gasket, with engine running and cool spray carb cleaner or brake cleaner around base of tb were it bolts to intake. when it hits the bad area, should idle down and be normal for a second or 2. iac is possible,try this first since its so common and let me know

ICM idle control module, loc throttle body, it may be dirty, remove clean or replace, its easy..

Before you replace the fuel pump, I would check the cheaiper parts first. Such as fuel filter and injectors.

could be bad glow plugs or plug heaters, faulty wiring to the coil, vacuum leak.