Yes. And it there is a Merc. test to measure your drive pump's output. You need to do this in the water, because the garden hose flow can alter the results. Depending on your drive's gear ratio the pump should deliver between three and four gal/min at 1000 rpm. Ave is around 3.3 gal/min The procedure is to disconnect the out drive water supply hose where you can collect the pump discharge in a gallon container. An antifreeze jug works nicely. Merc. stresses taking a 15 second sample and shutting off the engine to protect the exhaust system from overheating.
Remember to do this a 1000 rpm. Measure the water in the container. 3 quarts=3 gal/min, 3.5 = 3.5 gal/min. etc. If you get this output, your pump is OK. If not, you should replace the impeller, especially if you are having cooling issues. Assuming good impeller efficiency the output will roughly double at 2000 rpm, triple at 3000 rpm, etc.
